Photography: Terms & Techniques

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This is a self learning. I am starting this. It will grow only by the contributions of experts here... I just copy and paste their contributions in the proper places. I am just an editor, not a director. This is a long term process.... Request your support

A modification:
Information in Red: basics or Very essential
Information in Green: Good to know
Information in Blue: Deep Philosophy

Regards

Latest edition on: Aperture / Bokeh/Hyper focal distance/Circle of Confusion/Diffraction/ISO/Shutter speed/Panning/Panorama/ Exposure Compensation/Aperture Priority/Shutter Priority/Front Lighting/Out of Focus/Composition/Perspective/Lens/Tripod
/Zoom/White Balance/AEB/Program Mode/Flare/Glare/Rule of Third/Prime Lens/Normal Lens/ Tele Photo Lens/Wide Angle Lens/Macro Lens/Macro Photography/Neutral density filters/Eye/Polarizing Filters/HDR/Zoom Burst/Pin Cushion Distortion/Barrel Distortion/Shutter lag/Vignetting/Shutter Mechanism/Rear Curtain Flash Synchronization/Straight Out Of Camera/Histogram/EXIF/JPEG/RAW file/Color Space/Posterization/Gray Card/Full Frame Sensor/Mirror Lock up/Bulb/Magnification/Quick Control Button/Under Exposure/ Over Exposure/High Key/Low Key Image/Light Painting/Extension Tube/ Tele Convertor/Silhouette/Noise/Blur/Rembrandt Lighting/Chiaroscuro/Key Light/Fill Light/Back Light(studio)/Rim Light/Through The Lens(Flash) Metering, TTL metering/Sweet Spot/X-ray Photography(Radiography)/Infra Red Imaging/Aspect Ratio/Bounce Lighting/Candid Photography/Contrast/Flat Image/Flat Lighting/Catch Light/Red eye Effect/ Red Eye Reduction/Parallax/Panning/Point Of Interest(POI)/Soft Box/Light Box/Patterns

Sunny 16 Rule/Negative Space/Artifacts/Batch Processing/Gel/Golden Rectangle/Digital Zoom/Backdrop/Blown out/Kicker/Dominant Object/Photogenic/Broad Light/Short Light/Monopod(Unipod)/Mask/Time Exposure/Incident light/Golden Hour (Magic Hour)/View Point/Dynamic Range/Aesthetics/ Inverse Square Law/Landscape/Leading Lines/Power line Challenge/Split Lighting/Selective Focusing/Head Shot/Recycle Time/Resolution/Key Stoning/Diopter Adjustment/Thumbnail/Burst mode(Continuous mode)/ CCD/ CMOS/ Colorcast/ Flash Assist/ Interpolation (Resampling)/ Gamma Correction/ Chromatic Aberration/Rainbow Rule

 

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Aesthetics:Aesthetics is a branch of philosophy dealing with the nature of art, beauty, and taste, with the creation and appreciation of beauty.It is more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste.[SUP][3][/SUP] More broadly, scholars in the field define aesthetics as "critical reflection on art, culture and nature. That was Wikipedia quoted.
Aesthetics is the one's emotional *** intellectual response to an object or an art form. Human aesthetics depends upon so many factors like, social, cultural and personal. Human senses serve as the devices for appreciation of an object or an event.
Aesthetics are related to human experiences and conditioning there from. We are all slaves of conditioning by experiences. If one happens to see a new born baby with a single eye only, on forehead the immediate feeling would be "how horrible"... Suppose all of us are born that way and also suppose one is born with two eyes as we all have,now. Then seeing that baby one's response would have been the same-"how horrible". In some aesthetic aspects we are all conservative. But in some other things like dress or hair style we may be able to appreciate an attractive novelty. Aesthetic can be affected even by the mood of the day. Those who might have witnessed a horrible murder of his/her dear one would develop a permanent hatred for the color red. So many of the aesthetics are conditioned ones.

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Ambient Light: It is the original light that exists in a place where a photo is going to be shot. Original light need not necessarily mean Natural light. It can be artificial light that is produced by an incandescent lamp, a set of burning candles etc. In other words no special light source like in-built flash or on-camera flash or external flash units are used by the photographer to achieve some desired result. In an out door photography sunlight can be the ambient light. Capturing images in ambient light can be a great challenge because there may not be sufficient light and some times there is too much of it. Some books recommend program mode as an easy way for achieving good results in shooting in ambient light with a tripod to avoid a possible hand shake, in case of a long exposure. Raising ISO must always be the last risk to be chosen. Ambient light is also called Existing Light or Available light.


Sometime outdoor ambient light brings out the richness of colors


Mother Nature gives the Best ambient lighting....
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Angle of View: This is the field of view expressed in terms of angle, covered by the lens we use. The two eyes of human together cover almost 180 degrees horizontally; at the same time each eye cover more than the half of it, that is more than 90 degree; this is easily understood since some common angle is covered by both the eyes. If you keep the face steady and close one eye alternately, you see some objects with both the eyes separately. This part of vision range which is seen by both the eyes is called binocular vision range. Actually only in this range distributed equally on either side of the vision axis (60 degree on either side) has the depth of field experience or three dimensional experience. The remaining 30 degree covered by each eye individually on the sides have no depth of field experience, which we seldom recognize. Remember, when we look in different angles the vision axis also change and so we see the depth of field in any direction we look.
Our vertical vision covers nearly 100 degree only, with a fixed face position. Human activities are mostly on the horizontal plane and so Nature restricted it that way. for most of the animals which are flightless like us, the range will be something like this.
Birds with two eyes placed almost diametrically opposite on two sides of face, almost 360 degree coverage is there in horizontal plane. But at the same time their binocular vision is restricted between (10-20) degree since the vision overlap is very less. Bird eye is more projected to give a wider vertical vision field

A lens is like a single eye. A lens with/at a smaller focal length has a wider field of view (wide angle lens/wide end)compared to lens with/at a longer focal length(telephoto lens/tele end). Human eye focal length is near about 22mm.
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Aperture:It is the opening in the diaphragm between the lens system and the sensor/film that decides the quantity and the quality(this in the sense of extent of diffraction) of the light reaching the sensor. Aperture system is made up of a definite number of blades that closes or opens like human iris. The opening is a symmetrical polygon with as many sides as the number of blades; greater the number of blades greater the circularity of the polygon.

When the aperture is small in size the quantity of light reaching the sensor is less, which requires a slow shutter to achieve the required exposure; conversely, a wider aperture means entry of more photons reaching the sensor in a given interval of time and so fast shutter to attain the required exposure. That was regarding the quantity-control of photons using aperture adjustments.

Now regarding the quality of the light rays. A wider aperture permits the entry of large number of non-parallel beams of light. If this happened the sharpness of the image will be restricted to a small range resulting in low depth of field of image. Conversely if a small aperture is used most of the non parallel rays are cut off and a thinner pencil of parallel rays( called collimated rays) alone reaches the sensor giving sharpness of image over a greater focal range and so depth of field in the image is greater.

Thus in creative exposure, a photographer is left with two choices-either to give a narrow DOF image with foreground and background of the selected object being out of focus or to achieve an image with greater depth of field. At the same time the former demands a fast shutter that freezes the action if any(for instance, a "frozen" water falls), where as the latter demands a slow shutter that registers movement with blurring effects( for instance, a silky water falls).

In physics terminology, aperture refers to the diameter of the central part of the lens which is effectively available for transmitting light. Intensity of light passing through the aperture is proportional to the square of aperture value. Naturally greater the amount of light entering thus, more is the number of photons to register the details in an image.

Reducing the aperture enhances another problem called diffraction. Diffraction is the phenomena in which light rays are bent over the sharp edges of an opaque object in their path where by many rays go non parallel and away from the track of the parallel rays. When the aperture size(radius) is reduced the ratio of edge length to cross section of aperture, that is (2 x pi x radius)/( pi x radius x radius) = (2/radius) increases, which means a greater chance of more radiations to be diffracted away from the parallel rays reaching sensor. This would definitely adversely affect the quality of the image.

Diffraction in turn can deteriorate the image in some other way, through another optical phenomena called interference. Due to diffraction, light radiations develop path differences (here wave nature of light is the basis)which leads to constructive and destructive interference of light beams where by some are enhanced and some are partially or completely annihilated.

A small aperture (here f/22) leads to greater refraction and light source may appear starry .
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Aperture Priority: This is one of the exposure mode available in all cameras. In this mode user decides which aperture needs be set, depending upon the Depth of Field requirement. Aperture values vary as f/2.8, f/4, f/5.6........ f/22 etc. greater the number seen in the value, smaller the aperture, greater the depth of field in the image. But a smaller aperture (bigger f value) also means less number of photons reaching the sensor. So shutter speed will be low accordingly. This warrants camera shake and a tripod is always desirable.
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Artifacts:...or artefacts are the undesirable elements that develops in an image due to various kinds of post processing. Repeated operations degrade image quality very much. Even enhanced level of noise can result as an artifact.
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Automatic Exposure Balancing, AEB: This is an in-camera set up that permits you to capture three images at one click which are having three equidistant exposures. The exposure can be selected in up/down of multiples of 1/3 values up to plus/minus 3, like (-1/3; +1/3), (-2/3; +2/3).... (-3; +3). Thus you have one image at selected exposure, another one under exposed by the stop you selected and a third one over exposed by the same stop value. If you have selected continuous shoot mode, a single click will capture all the three images. AEB is used under the following situations:
# The lighting is mixed which can fool the camera metering
# You are not sure which will give a better drama to the scene like sunset
#You cannot afford to waste time between consecutive shots of the same scene with different exposures
# You want to create HDR images
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Aspect Ratio:This is regarding the size of the image expressed as ratio of horizontal length to the vertical length, that is width: height, as x:y . It can be expressed with respect to the original digital image or its modifications, or monitor image or print size etc. If width is more than height, they belong the general category called "landscape", where as if height is more and width is less it is the "portrait" type. The common aspect ratios used for still images are 4:3, 3:2, 16:9, 5:4, 5:3 and 1:1(square) in landscape modes or the inverses of these in portrait modes.How you present an image -the proportion of sides very much affects the appeal of the content. So this is very important. If the original image has an unsuitable aspect ratio, it can be modified by trimming suitably later in manual mode, but losing some elements in the frame. Most photo editing soft wares permit maintain the chosen aspect ratio when you select a desired width or height.
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Backdrop:The backgrounds used in studios. Plane clothes of different colors are used.
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Back-lighting: Lighting of an object can be done from several positions with respect to the object that is being photographed. If the light source is natural, the object has to be positioned differently to front-light, back -light or side-light etc. On the other hand, if a movable light source is used, it can be placed at different positions to achieve the desired lighting. When sun is the light source it is always the object that has to be moved to achieve the desired lighting. If Sun is the light source and the object is also static like a tree, one has to choose proper timing for front lighting, back lighting etc.

If the light falls on the object from the same side from where the photograph is taken , it is called front lighting and in this case the light source is by the side of/behind the photographer. On the other hand if the light source and photographer are on opposite side of the object to be photographed, the object is back-lighted.

Back-lighting can make several creative lighting effects. If the object is translucent as in the case of flowers, leaves etc., it can bring glowing effect to the object. another important application of back lighting is to create wonderful silhouette. They are much used in portraiture also. They are very helpful to bring out the outlines of architectural works.


Here back lighting on dark clouds creates some luminous effects



Back light on a leaf reveals its inner patterns; it also adds a glow to the leaf


In a back-lit image, source of light may be included to get a desired result


Back-lighting creates beautiful silhouettes



The translucency of petals makes back lighting a good creative tool in floral photography
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Back Light(Studio): It is used along with key light and fill light to complete the basic three point lighting in studio photography. It is also called rim lighting. It is used to build a border lighting around the head and/or sides to feel the projection from the background. Rim light is placed against the key light behind the subject, above head focusing behind head or on to head. It is at more heights than key light fill lights. Its brightness can be adjusted to suit the required level of border illumination.
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Barrel Distortion:It is a distortion where by the image shows a bulge out in the middle , giving the look of a barrel. It is seen when a wide angle lens is used at its wide end. It happens due to decreasing magnification away from the principal axis of the lens

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Batch Processing: This is the processing software technology which permits the user to select a set of images and subject them to same kind of processing in one go, if they are having similarly editable problems, like adjusting brightness.
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Blown Out: Thepart of the image which has been over exposed removing all details, creating plane white patches. Some times this can add a punch to the image, but mostly spoils.




Blur:It is the phenomena in which the image loses sharpness and appears diffused. It can arise due to hand shake, especially when a slow shutter speed is applied. Even when a tripod is used, a slow shutter can cause blur if the image moves even slightly. Blur is sometimes deliberately included to bring the sense of movement.



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Bokeh:This word originated from Japanese, where the word meant blur or out of focus. It is one of the creative element in photography, which photographers wisely incorporate to achieve dramatic effects. A good bokeh enhances the effectiveness of the image. While we use a wide aperture, the background is seldom sharp and changes to colorful bokeh. All bright spots in the background are seen as diffused light patches. The shape of such patches depend upon aperture; if it is perfectly circular, we get circular patches; sometimes it appears like polygons too. The most common application of bokeh is in many portraits.



A nice bokeh enhances the beauty of the image without distracting

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Bounce Lighting: This is a studio lighting to get a ambient light effect. The The light can be bounced from different surfaces like ceiling, white wall, special kind of umbrellas, aluminium foil etc. Golden hue can be achieved by using a shining golden papers. Bounce light can be used as fill light also.
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Broad Light:This is a studio lighting set up where the camera sees the face at an angle and the key light illumines the face on the same side which the camera faces. This gives the face a chubby look removing the details from the face; the counter lighting is short light
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Bulb: This is the extreme shutter release mode where camera does not close the shutter by itself once the shutter release button is depressed to capture the image. The photographer has to decide when to stop the exposure by releasing the button. Usually this is used for long time exposures as for night sky photography, lightning photography (when you are not sure when lightning will flash) , shooting traffic light trails, fire works etc. To use bulb mode always use tripod and use shutter release cable to avoid possible shakes.
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Burst Mode: This option in Cameras lets photographer capture 3, 5 or eight or more frames captured in a second by a single click. it is very useful in sports, birds in flight, animals in action and many journalistic images. This mode also known as continuous mode.

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Candid Photography: It is related to the attitude of the person(s) being photographed. It is mostly captured mostly if not always unawares. It has a lighter or funny content. Mostly it is about an action or expression that sounds funny or interesting. It should not be mistaken to be a snapshot. A snapshot suggests the careless attitude of the photographer where is a candid image is about the care free attitude of the person who is being photographed. A candid image can be a well thought and well composed too, if the photographer is prepared for it.





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Catch Light: This is the light you find reflected from the cornea of the eyes in the portraits of human beings, animals, birds etc. Catch light gives life to eyes and so to the portrait. We feel the glow of eye only if catch light is there. Since pupil, the aperture of eye absorbs almost all light falling on it, reflection is mostly from the iris, underneath the sheath of the cornea( if light source is not straight in front the eyes, slanted light rays may suffer total internal reflection from the inner layer of cornea in front of the pupil, appearing as bright spots at pupil. Having bright patch of light there can spoil the image; so it is always better to keep catch light outside pupil. Big patches of catch lights on the pupils would give a blind-eyes feeling) In studio portraiture catch light is specially added to give distinct effect. The reflection pattern can be spherical spots or rectangles depending upon the light source. If the catch light is the light entering through a window or door it appears as beautiful rectangles. Without catch light a person's image may look evil and so sometimes catch light is removed from eyes to give a required bad impression.

Catch lights are non-detailed bright patches. At the same time cornea can act as a mirror too where we see the world around reflected in the eye. It is of special interest to many photographers to capture the reflected image in the eye of a person.


At least a speck of catch light is essential in portraits



Catch light is important for All eyes


She catches you because of those catch lights




Eyes can act as mirrors reflecting the word around....


Why, catch light can add life even on a pair of glasses :mrgreen:


...and now you know why catch light is so important

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CCD:Charged Coupled Device- This is the light sensitive chip that receives the photons and record it as an image. It has analogue sensors and the data collected is later converted to digital information and recorded.
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Chromatic Aberration: This is a problem with tele lens and super tele lens with wide apertures. The issue is the convergence of the different wavelengths of the component of lights at different focal planes- blues converge at a nearer distance where as reds converge at a greater distant plane. The outcome is the overall blurring of the image
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Circle of Confusion,CoC: This is a concept related to the depth of field. The change of DoF is not abrupt but gradual. If a spot in the image does not grow into a visible point of blur, when printed 8 x 10 inch and viewed from the convenient distance of one foot by a person with normal vision abilities, the circle of confusion is tolerable. Conversely if it is an evident blur then we say the DoF is diffraction limited, since the blur can be an outcome of diffraction. The blur behind the range of DoF are considered as Bokeh. When ever CoC outgrow the pixel size beyond a limit, it leads to a visible deterioration
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Close Up: This is regarding the size of image formed on the sensor of the camera with respect to the original size of the object. Close ups are categorized into three as moderate close up, close up and extreme close up. Close ups have the magnification ratio ranging 1:4 to 1:2. Close ups are not to be mistaken as macro photographs since the latter has the magnifications in the range 1:1 (life size) to 4:1. A macro image is a close up image too, but close ups are not macro. Some lenses have their tele end specified as macro; but that is not strictly correct, because they don't give this much magnification. Tele lens give close ups even from distances where as macro lens give extreme close ups ,but needs be focused from closer distances.


These images are reasonably good for comparing close up and macro


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Colo(u)r:Color is the visual sensation caused by electromagnetic radiations in normal human eyes. Is your blue, my blue? We have to believe so Different wavelengths create different disturbances in human brain leading to the vision of different colors. Human eyes have response to a very narrow range if we take the whole solar spectrum into consideration. Beyond the "violet sensation" and "red sensation", our eyes are blind, so to say. We can not see in infrared light or higher wavelengths not we can see in ultralight or lower wavelengths. Black is not actually a color. That which generates no visual sensation appears black... so can i say what you don't see is black?

In darkness there is no color to anything, because bodies appear colored as a result of their interaction with light. if there is no cause, there can be no effect too.

Nature's Colors are wonderful....

Kerala's Art Form, Kathakali is World renown for its expressiveness and extravaganza of colors

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Contrast:If an image has distinct bright and dark regions, it is said to have good contrast. If black and white approaches to mid gray, the image has low contrast. A totally bright image and a completely dark image, both lacks contrast.The term Density is also used to mean contrast.

Visibly there is good contrast

....and poorly contrasted
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Chiaro Scuro:This term originated from "Clair-Obsure" suggesting light and shade. So this term suggests the use of light and shade in portraiture in such a way that they synergestically enhance the appeal. Almost all images are composed of light and shade, but here, more than the colors it is the light and shade that catch one's attention. Rembrandt lighting is a very good case of Chiaroscuro effect.

A half lit face can tell a full story

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CMOS:Complementary Metal Oxide semiconductor, it is. Like CCD, this is another chip to record images. It has two advantages over CCD chip. One is that its power consumption is low as its wastage of power as heat is low. Second, it produces less noise
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Colorcast: The event in which the image acquires some dominant color like green, magenta etc. It can happen either due to a wrong presetting in the camera or by a wrong processing.
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Colorspace:The real significance of this term emerges from another term called color model which is mathematical and very complex. For practical purpose we can talk about its physical counterpart named color space which is a spacial system/presentation of colors based on three basic colors such as Red, Blue and Green (RGB) or the set of secondary colors Cyan, Yellow, Magenta along with Black(CYMK) and every color can be produced by a combination of these colors in definite proportion.

Every image requires a set of colors for its visual presentation which may be called the color gamut for that particular image. The same image when presented in two different color spaces like CMYK and RGB, the color gamut of the image suffers some change.Some color that can be presented in RGB space cannot be presented in CYMK. Technically some colors are said to go out of the color gamut while color space is changed.
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Composition: This is where a photographer's aesthetic sense has to work. It demands more than technological awareness. Whether you shoot with a point and shoot or with a high end DSLR, make less difference here.

This is how you are going to view a scene in your own way, interpret with your own visual language. You are the one to decide from which angle you have to capture the event. What all elements need be within the frame and what all should be kept out. All occasions may not give you the full freedom to compose your frame as you really wanted that to be. So one has to bring the best out of constraints of the situation.

Your camera lets you focus first and recompose to position different objects in the frame as you wish. That is a great blessing while composing an image. More than any thing it is the way you compose an image that reflects the real talent in you. All technical wisdom can be acquired in the course of time....


It will be always nice to keep the main subject off center with more space in front of it than behind it



A landscape is seen more horizontal than vertical since our horizontal angle of vision is more than vertical. Hence the term "Landscape mode"


However which orientation need be chosen depends upon what kind of object you are going to show; a water fall , a tree, a cascading stream etc work well with the so called "Portrait mode"




Sometimes, it is better to maintain some depth of field to suggest the nature of place, than pushing it into a mere bokeh



Isolating faces and flowers in a dark background, with patial diffusion is a good idea of composition


The composition has the weakness that the main subject being very near to the center of the frame.
It would be better placed at the right bottom of the four golden points.


An animal walking towards the observer has greater impact


Symmetry can be the point of interest

 

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Depth Of Field, DoF:It is the available depth in the field where objects are found reasonably sharp. A wider aperture results in low DoF where as a constricted one gives greater DoF. DoF is most desirable for landscapes, street-scapes, cityscapes etc. Conversely it is undesirable for portraiture especially when there are distracting objects behind, in a natural settings.

Since a narrow aperture limits the quantum of light entering through the lens, problems of low light may arise. This could be overcome by a longer exposure and/or a higher ISO. If the situation has low light, longer exposure is preferred to boosting ISO, to minimize noise.

The DoF distribution in front and behind the principal focal plane depends upon the focal length chosen. For instance at a focal length of 10mm, the distribution of DoF in front and behind is in the ratio 30:70; at f-20mm: it is 40:60; at f-50mm it is 45:55; from there onwards the ratio change very slowly and even at f-400mm it is 50:50 (all ratios are approximated)



A smaller aperture gives good depth of field...
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A larger aperture produces shallow depth of field


When we focus not on the nearest part with a low DoF, only the middle part is in focus; sometime it is not a good thing to happen as is here

Depth of field is very important in landscapes
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Diffraction: This is an optical phenomena. Light bent around sharp opaque edges on its path and progress in conical path than in parallel ones. Light radiations originated from the same source will have wave patterns moving in unison. However due to diffraction waves develop path differences and such waves interact with one another, where by light beams either strengthen, weaken or even destroy one another. This in turn affects the image that is captured on the sensor.
When we reduce aperture, the edge length available with respect to a given cross section of light beam increase and so effect of diffraction increase. Thus the benefit of having a greater DoF is compromised to some extent.

In the sensor there are more pixels dedicated to green than to blue and red. So diffraction affects the resolution of green than blue or red in the image. Naturally if the landscape has more green than blue or red, the adverse effect will be more pronounced.
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Digital Zoom: Zoom generally leads to enlargement of the image. its purpose is to get more details from a selected area. There are two options - optical zoom and digital zoom. In the former zoom is achieved optically without losing the image quality, because the lens system gathers sufficient information from the enlarged area. But in digital zooming, the process is not optical and so more than zoom, it is something like stretched enlargement of the a smaller portion to attain the aspect ratio of the original image. Naturally there will be less information to fill a greater area, degrading the image quality. If the sensor has high pixel count, digital zoom will not do much harm. But digital zoom is not advisable using a camera of low pixel count. Digital zoom can be done in post processing. But optical zoom ends with clicking.

This image was @55mm

This image is an optical zoom of the above scene @250mm



This image was trimmed out, that is digitally zoomed in from the first image @55mm, with nearly comparable framing to the image immediately above @250. There is enough loss of details to worry

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Diopter adjustment: Even though lens capabilities are fixed,human eye capabilities vary from person to person. Diopter adjustment knob can be rolled up or down to acquire visual clarity. Under perfect adjustment of diopter, photographer's eye works in unison with camera's eye, the lens. What lens sees sharp is seen sharp by human eye also
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Dominant Object: As the very words suggest, it is the most striking subject within the frame to which the photographer intends to draw the attention of the viewer. This is not to be placed at the exact center of the frame. This is also called a point of interest. In the image the viewer's attention can be drawn to the dominant or main object in different ways like using leading lines(a fence, a track etc), blurring the surroundings( to bokeh), keeping the main object highlighted keeping other objects darker( as a face), having the main object a different color (a flower or chair with different color from others) etc.

A main object is different from The Main Subject. It is the main theme within a frame. For instance in an image, a person is seen to repair a machine. Here the person is the main object and the machine he is working on is the supporting object( However this may vary from viewer to viewer, depending upon the tastes and tendencies. For instance, for a person who is more interested in machines, the main object is the machine which is the first thing that drags his attention.) The main subject in the image is "the labor" or "the work" to express which in visual language the man and his machine are used.


Here the main object is The Photographer himself, less so the camera which is not much available in the image where as the main subject is Photography


Here the the glowing clouds appear to spread out from an other wise non-prominent telecommunication tower and technically this tower is the main object; but the eyes would come back to search or revel in those ruddy glowing clouds; so man made rules are sometimes broken by personal experiences.

Color can be the dominant subject....
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Dynamic Range: The range from brightest to the darkest regions included in an image. Greater the dynamic range, greater the contrast. An image with poor contrast has a low dynamic range. It is difficult to get both extreme within an image without blown out and black out regions of no details. HDR imaging is a post processing where images of various exposures are super imposed to get details from every where within the image. Dynamic range is also called Tonal range.

 

[Bitter Jeweler]

http://www.thephotoforum.com/forum/...rum/167288-camera-terms-acronyms-dummies.html


Have fun!

 

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EXIF: This is the popular acronym for EXchangeable Image File. Even those who don't know its full form know what it is. Like histogram, it is a collection of information (metadata) regarding a photograph, and unlike histogram, it is not graphical but a collection of statements/values etc. Most of the new generation cameras record all connected information regarding an image in the very image as retrievable data. You can verify them in the camera or in many photo editing soft wares like Picasa etc. Many dedicated Exif readers are also there.

Exif data includes date and time of image captured, the camera make, exposure details(shutter speed, aperture, ISO), orientation, white balance and more. If the camera has active GPS system, the location information will also be available in Exif.

To learn photography in depth, studying histogram and Exif are always recommended. it helps one to realize how the camera has to be adjusted in different conditions for the best result.
*EXIF is applicable to JPEG, TIFF, RAW etc files
*A link to an EXIF analyzer: http://exifdata.com/exif.php
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Exposure Compensation: This is an adjustment available in camera to fine tune exposure. Some times a bright parts of the scene fools camera's light metering that it under exposes the image, turning whites to dull grey and low light regions too dark. Like wise if a scene has dominant darker objects camera is confused and over exposes removing details. Exposure compensation is applied in such situations
Exposure compensation is available in the range +2/-2 ; in some camera it goes up to +5/-5. and compensation can be done in steps of +1/3 and -1/3.

How camera adjusts exposure is either by changing the shutter speed or by aperture or both, depending upon the priority mode, the camera is chosen to work. If camera is in aperture priority mode with a selected aperture value, any adjustment in exposure will alter the shutter speed; conversely if camera is in shutter priority mode, any adjustment in exposure would alter f-number. In program mode also shutter speed is adjusted during exposure compensation.


Under exposing can sometime works well.....At least some would like it that way....


Sometimes low light is better......
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Extension Tube: This is a hollow tube that is connected between the lens body and lens socket of the camera where by the distance between the lens group and the image sensor has increased. greater this distance, smaller the focal length and greater the magnification. This is much useful in macro photography and close ups
Extension tube has the following limitations. Most of them do not have any optical element, nor any electronic set up by which they can connect the lens circuitry with the camera. So once the extension tube is connected, no more automatic functions are available. Manual focusing has to be done. Further the extension leads to lowering of light and so a greater time span is required for exposure. Extension tube should not me mistaken to be a tele convertor. Its low price is its great attraction.
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Eye: Human brain is the most wonderful thing so far known to us and Human eye must be considered the next best thing. If one day you are warned of losing two of the sense powers among vision, audibility and power of speech and can opt to retain one only, most, i think would retain the power to see.
Eye is the inbuilt camera of human body. There are much to compare( with some minor variations)
The Cornea + lens behind = The lens unit
The Schlerotic chamber (the eye bulb) = The camera body
The Limbus = The lens camera body connector
The Eye lid = Lens cap
The Iris = The diaphragm (We all differ in colors of it)
The Pupil= The Aperture (It appears black since light entering never comes back; from where no light reaches your eye appears black) (f/2.1 in dark to f/8.3 in bright)
The Zonule = The image stabilizing system
The Retina = The sensor
The Ganglion cells, Rod cells and Cone cells = The pixels
# Eye can recognize about a million of colors and their shades together
#Eye is not a complete sphere; the cornea part is like a bulge on the sphere
#Through the transparent cornea we see iris and pupil
#Eye grows only upto 13 years
# The volume of eye globe is about 6.5ml, weighing 7.5 gram and so having an average density 1.154g/ml, slightly more than that of water.

 

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Fill Light:This is a supporting light to drive away unwanted shadow/shade from where key light cannot reach. It is always less intense than key light. If fill light is less than half the strength of the key light, image resulted will have greater contrast where as if the fill light has nearing key light in intensity, the image will have low contrast. Some times a reflector that bounces the key light to the other side like a moon reflects sunlight, can do the role of a fill light. The fill light: key light ratio can be varied from 0:1 to 1:1. In the former extreme, one side of the face will be almost submerged in darkness where as in the final ratio, the face is uniformly illumined on either side. The contrast will be maximum in the first case and least for the last case

What this image dearly wanted was a fill light... :camera:
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Flare: This is an intruder into your sensor through the lens. They are the stray light beams that reach sensor which start from the original light source or other light sources or some strongly reflecting surfaces. They enter into the lens through awkward angles and creates tracks and patterns of burning light patches. In most cases they spoil the quality of the image except in some cases where they enhance the beauty of a landscape, like that of a Rising Sun etc.

It happens mostly when light source is in front of the camera. The uninvited light beams enter the lens groups, getting reflected from several lens surfaces and shuttle there several times; a part is lost to outside before the shutter closes where as another part becomes successful in reaching the sensor and doing harm. Flare some times may mask a major part of the image when it is called a veiling flare. The polygonal patches, acquire their shape from lens diaphragm and may have colors due to diffraction.

Lesser the number of lenses in lens group, lesser the effect of flare. So prime lenses are expected to produce little flare. Lenses are now designed with non reflecting coatings to minimize flaring. Lens hoods are also helpful in preventing flaring light beams entering the lens. Additional filters we use may increase the problem of flaring by adding to the number of reflecting surfaces.

Lens hoods some times create shades in the image if hood comes in the angle of view of the lens. Petal shaped lens hood have the advantage that they have smaller petals on the two sides which when comes horizontally on either side of the lens will not come in the angle of view of the lens.

Flare is not always bad....
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Flash Assist: This is the pre-flashes send by the camera -sometimes infra red light- in low light or in darkness to calculate the distance to the subject and thus to calculate the required output.
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Flat Image:An image with poor contrast

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Flat Lighting: The lighting that removes contrasts as in portraiture; they by removing shadows remove the contrasts too.
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Front Lighting:The object photographed gets light from front. This can be from the flash light on camera or any supportive lighting or even from natural light like Sun light. Front lighting causes undesirable shadows in portraits which can be controlled by using fill in flash which can be used even in direct sunlight. Harsh front lighting mostly spoils an image, takes the beauty of color and texture.



Selective front lighting can be some times magical...

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Full Frame Sensor: A full frame sensor has the same size as a 35mm(36mm x 24mm) film frame *Other DSLR camras, compact cameras and mobile cameras make use of decreasingly smaller sensors in the order.
*Lenses designed for full frame sensor cameras may be used on normal DSLR cameras, but the problem is that only what the central image circle of the lens captures will be registered on the sensor
*The ratio of sensor size of full frame to that of other smaller sensor is called the Crop Factor
* Greater the crop factor for a given sensor, smaller its size, which means lesser angle of view registered on the sensor for a given focal length using the same lens.
* Usually crop factor ranges between 1.3 to 2 from bigger sensor to smaller sensor.
*Crop factor is also called focal length multiplier.
*For a given aperture (f-number) and at given angle of view, full frame sensor requires greater focal length and yield lesser DoF( For a smaller sensor camera , to cover the same angle of view smaller focal length is required and DoF will be more)
* Full frame camera along with a wide angle lens is very useful in architectural photography which demands wider perspective
* A full frame sensor has greater number of pixels to capture the light and so very useful in low light photography, without generation of noise
* With the crop factor, small sensor cameras give better telephoto effect for a given focal length. So if you has a tele lens with 200mm focal length, it gives the same tele effect of a 300mm lens on a full frame camera, which will be very helpful in wild life photography.
* Full frame cameras are less common among photographers for their heavy price tags that result from the heavy production cost of full frame sensors.

 

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​G g :mrgreen: g G g :gah: G g g G g G :hippie: g G G :???: g G g:bounce: G :cheers: G :hail: G
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Gamma Correction: This is the adjustment of the contrast of an image as seen on a monitor. A high gamma suggests washed out image where as low gamma stands for a low contrast image.
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Gel: Gel is made of gelatin, glass or any polymeric transparent material with different colors. They produce different colors individually or in superimposition. The soft box or flash light is covered with the gel sheets to change colors. They can be used to adjust white balance of a scene, to add selective colors-say on hair through back light, or for shading the whole back drop with matching or contrasting colors in studio portraits.
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Glare: It is harsh or brilliant light,seen on the objects which is generally considered not suitable for good photography because such light spoils details, cause harsh shadows and take away the charm of colors. Glare is different from flare in that in the flare we see additional light streaks or light patches where as in glare the brilliant objects like a glowing sun or reflecting surface etc. directly disturbing vision. Glaring can be removed by either changing the time or angle of photo taking. Using appropriate filters can also buffer the harshness of light. A heavy glare on the background turns the object silhouetted.
In flare the source of light may not be within the frame. But in glare the source of light- a glowing body or a reflector- is withing the frame; if stray light causes flare, direct light causes glare


Glare is not always unwelcome



Brilliant glares can convert the objects to beautiful silhouettes


Flare and Glare sometimes happen together; Flare is seen only in an image, where as glare is visible to eyes and lens
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Golden Hour(Magic Hour): This is the most suitable time for worry free photography. This is one hour just after the Sunrise and One hour before the Sunset. Golden Hour Light has the following features
* There is no harsh light that would over expose and also creates dark shadows
*Shadows are elongated and story telling
*If Sun is behind clouds, there are no shadows and light is uniform, with generation of less contrasts
* The light is best for portrait photography; it gives richness to human skin tones.
* The scope of silhouette photography is maximum
*The best time for landscape photography
*The only time you can include Sun in the frame without much problems to sensor and the eyes
* Through out the golden hour the quality of light keeps on changing and the photographer is bestowed with an hour for experimentation
*If a place is front lighted in the morning, the same place is back lighted in the evening and vice versa. So photographer can choose to go for which or both

In Golden hour, you can include Sun within the frame with less concerns; in the morning the additional bonus is the mist

No wonder why this time is called Golden Hour and Magic Hour

The best time for silhouette...

Golden hour is ideal for Landscape photography




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Golden Rectangle:It is the scientifically approved aspect ratio which is visually most pleasing. It is 1.618:1= 3.236:2,which is nearly the aspect ratio of 35mm format, 36:24= 3:2.
If we divide this area into 3 x 3 = 9 identical rectangles by two sets of two equidistant lines horizontally and vertically, all those rectangles will be golden rectangles. This is the secret of the "Rule of Thirds". and the four corners of the central rectangle are the "Sweet points".



3.236:2 is the aspect ratio that is visually most pleasing to normal human eyes
(Some times this ratio is approximated to 3:2)
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Gray Card:This is a reference to set the standard of exposure. A gray card is card of neutral gray color( that is not inclined to black end or white end) with nearly 18% reflectance over visible spectrum.
Before taking a photo from a lighting condition where there is a greater chance that the camera misreads the light, a gray card can be of help. Placing the gray card on a spot where an object is going to get placed, so that the gray card gets the same light as the object that would be placed latter. Take the exposure reading and lock the exposure. when the object is latter placed there and photographed, it will be properly exposed.

Gray card can also be used for white balance reference. For this take an image of gray card in in normal lighting conditions and take this as the custom white balance reference.

 

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​H hh h h h:crazy: h:violin: h :blush2: h :cyclops: hHHh
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Head Shot: Image of a person showing him from shoulder upwards, mostly showing him facing camera wards. Head shots are mostly meant for familiarizing the person than to sketch his character.

In some cases a head shot reveals the personality

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High Dynamic Range Exposures, HDR: When a selected frame to be photographed has a great tonal range from very bright to very dark areas, that could not be captured by any selected exposure setting, we go for this more or less novel technology. It is an ex-camera post processing. Human eyes register and recognize the brightness and darkness falling within a range of nearly 16 stops. In HDR we are trying to attain some quality nearing this, like 10-15 exposure ranges. so that one gets details from every spot of the image removing over exposures and under exposures.
All kind of images are not meant to be converted to HDR. Only when an image has the potent range to be explored, HDR is meaningful. By applying exposure bracketing get 3, 5 or 7 images which are moved from one another in one stop with respect to others, from a too bright one to the dark one. Now feed them to the software which offers HDR processing capability. They super impose the images in such a way that the best outcome is resulted with respect to every point in the image. The processing is complete after tone mapping the image to the required saturation of colors. You can purchase or run trial versions of HDR editing softwares like www.photomatrix.com or www.hdrsoft.com
*Since even minor displacement of objects in the frame of individual images can affect the super imposing and mixing of images, it is very essential that the images are taken using a tripod
*A single image can be used for a lesser quality HDR by saving the image with adjusted brightness and darkness at five different levels.
* Picasa editor (www.picasa.com) has a single click HDR converion option which just hints to what an HDR image would look like
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High-Key Imaging: A different type of exposure where the image is uniformly brightened-without evoking the feeling of a bad over exposure- shadows being buffered down. The image lacks contrast. It is very fine for portraiture, floral photography etc.
A three- light system from front, and two sides to drive away harsh shadows is used. High key image is always pleasing to watch with some un-earthy appeal. It has a constricted tonal range. It works well with color as well as black and white imaging.





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Histogram: How important electrocardiogram (ECG) in understanding the healthy functioning of heart, that much important is a histogram in suggesting the exposure balance of an image. A wise professional gets good information regarding the quality of an image by looking at its histogram. Some creative excellent works may defy the rules of histogram, though.
A black & white histogram has 256 vertical divisions ranging frm values zero to 255. the value zero corresponds to total back and 255 corresponds pure white. all the intermediate shades come in between irrespective of their colors, in terms of their grey equivalents.
The zero is on the left end and 255 on the right end. the height to which this column filled suggests the excess/deficiency of that shade in the image. If an image has a histogram shifted most to the left with high peaks, it is an under exposed image with too much dark elements. Conversely if an image is mostly towards right it is too bright. If the peak is restricted to the middle the image is neither too dark nor too bright, but lacks contrast. An ideal images histogram with good dynamic range will have a nearly uniform distribution of the heights which slopes down at two ends to exclude extreme dark and extreme bright regions. it is very useful if one verify histogram of every image taken, so that the language of histogram is thoroughly understood, which would be a strong tool to judge the quality of one's own images in future.

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Hyperfocal distnace: It is the minimum distance(H) at which one should do the principal focusing so that all the objects from a distance H/2 up to infinity are in good focus in the final image. A knowledge of hyper focus is very useful while shooting landscapes, where it is desirable to have good depth of field. Since landscapes are mostly taken using smaller focal lengths, hyper focal distances are best suited for smaller focal lengths.

For a given aperture value, greater the focal length, greater the hyperfocal distance. For instance, for an aperture of f/2.8, the focal length(mm)/hyper focal distance,H(m) : 18/5.8 24/10.3 35/21.9 50/44.6 85/129 135/325.4 200/714.3

Again for a given focal length, greater the aperture number(smaller the aperture), smaller the hyper focal distance. For example, for a focal length of 18 mm, aperture value/H(in meter) are: 2.8/5.8 4/4.1 5.6/2.9 8/2 11/1.5 16/1 22/0.7 32/0.5

This leads to the conclusion that minimum hyper focal distance and maximum depth of field is available with the smallest aperture and at the smallest focal length.

To achieve hyperfocal distance first focus on something that appears most distant in the frame. Then manually adjust focus to nearby object in the frame and see which is the most near by object that appears sharp, while still having the distant object with acceptable sharpness in the background. Then all the objects from half the hyper focal distance to infinity will be in good sharpness in the final image. Remember the depth of field and the sharpness we observe through the camera is slightly different from what the lens really sees and reproduces. To see what is the real depth of field achieved by the camera, the depth of field preview button can be used.

Photography is pure science on one side and for every statement of aesthetics there will be a corresponding equation. For instance the equation for hyper focal distance,

Here f = focal length chosen; N = f-number; c= circle of minimum confusion (that is another confusion )
Circle of minimum confusion is the size of a point that which on a moderate size print when viewed at a normal handheld distance generates a feeling of visible blur

# Telephoto lens is not good for hyper focal purposes
# An approximate rule to get the effect of hyper focusing is to focus on to 1/3rd of the distance of the total field you want to be in focus
# Once focused at the hyper focus, the focusing should not be changed while recomposing.
# If you focus before or beyond hyper focus point, that would affect the depth of field

 

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​I i :hail: i :hug:: i i i :hugs: I i i i i :cheer: i i i iii :mrgreen: I I II :heart:iii :meh: iii
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Incident Light: The light directly falling on the subject from the light source. What we capture as images are the reflected light from the subjects, save the images where the light source is in the frame.
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Infrared Imaging: Just as we use visible part of the electromagnetic spectrum in normal photography, in infrared(IR) photography we use IR radiations to illuminate the object and the sensor captures and responds to infrared radiations. Infrared spectrum is divided as near infrared, which is just beyond red towards the higher wavelength region and even beyond that is the far IR. IR Photo imaging makes use of near IR, coming in the wavelength range of (700 to 900)nanometer(nm).All bodies on earth emit far IR radiations to greater or lesser quantities. This in turn is used in thermal imaging, as we see through the telescopes of the guns of many night fighters in movies.

In film IR imaging, the film which is sensitive to IR is also sensitive to visible part of the spectrum; so to cut off visible part, filters have to be used which are black or deep red in appearance. They absorb all visible radiations, permitting IR alone to pass through.

IR photography gives rise to magical black and white images or pseudo color images depending upon the film that is used. Digital cameras have constructional features which give them natural response to IR waves. However this can be problematic since visible focusing and IR focusing happen differently, that can trouble the auto focus system of the camera. Again the red color may appear over saturated. Surprisingly some clothe materials are transparent to IR radiations :blushing: . So most of DSLR camras have an auto filtering system against IR. In black and white IR imaging, sky would appear dark, the clouds would stand out bright, the green foliage appear snowy-bright- all adding to a fairy world effect to the scene. Night vision glasses and night photography without visible flashes make use of IR imaging techniques
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Interpolation:This is the process of increasing the size of the image by increasing the size or number of pixels. There are several variants to this like Nearest Neighbor Interpolation, Bilinear Interpolation, Bicubic Interpolation and Fractal Interpolation, with increasing quality in the given order.Interpolation is also known as resampling
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Inverse Square Law: This is not to be confused with the law in electrostatics with the same name. This is regarding the fall of light intensity with increasing distance. The intensity of the light falling on an object is inversely proportion to the square of distance of the object from the flash. So if the distance is doubled, intensity of light falls to one fourth; if distance increased three fold, intensity of light will fall to 1/9 th and so on.
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ISO:This is one of the corners of the exposure triangle. It adjusts the light sensitivity of the sensor. In DSLR cameras it has values like 100, 125, 160,200, 250, 320, 400, 500, 640, 800....1600...6400. Greater the ISO number more the sensitivity of the sensor to the light. Usually when the available light is low, one goes for higher ISO to capture the scene with more vividness. For this the sensor has to struggle more and this struggle results in the so called noise in the image that is developed later or seen on a wider screen.

If one does not want noise to dominate in the image, the best thing to do is to keep ISO as low as possible. But that is not always possible when available light is hardly sufficient to record the scene in front. If the frame has only still objects, one way to avoid noise is to go for a longer exposure with low ISO so that enough light reaches the sensor. If a deeper field view is not required, a wider aperture can be combined with low ISO to benefit from a noise free image.

Unlike aperture and shutter speed, this corner of the exposure triangle has no much creative applications, other than adding some grains, which some may like and most won't .

Cameras have the option for auto ISO and camera try to keep the ISO possible minimum for the required exposure; but don't blame your camera if that minimum is not low enough to keep away noiseIMG_0893,sm1
Here i wrongly chose an unwanted high shutter 1/640 and so my ISO was 3200!!! The image is full of noise


Here a low ISO of 100 helped minimize noise even though the light was low; aperture had to be f/5.6 for this, with a shutter speed 1/200 s

 

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​J jj :thumbup:j J j j j J J :flower:j j :sun: j j :mrgreen:J j J layball: JJJJJJ
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JPEG: This is the acronym for Joint Photographic Experts Group, who introduced this coding standard for photo images. JPEG has a definite codec (compression and decompression) to convert an image to an array of bites and back to the image; it makes use of a file format JFIF (JPEG File Interchange Format)
JPEG is a lossy format because it deletes any redundant pixel information, that it finds not essential for the normal reproduction of the image. So the file size will be small compared to other loss-less formats like TIFF. So, if every minute detail is important-as in a medical investigation data- JPEG is not the choice. JPEG supports EXIF data
When images are trimmed and enlarged there is a large drop in image quality for this reason. Even copying images several times can deteriorate the image quality. Why, even rotating image a large number of times can bring the quality down. Sometimes the bites of the image may increase due to various kinds of operations, mostly because of increased artifacts!!!
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K k k :cheer: K K K K K k :hail:k K :badangel:k K
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Key Light:It is the main light of illumination in studio photography. Usually it is used along with a fill light and a back light. It can be used as a single light source.
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Key Stoning: If the surface of a screen is not parallel to the lens, the screen appears distorted with near by edge wider and rear edge narrower. This kind of distortion is called key stoning. The name came from the shape of a key stone that looks like a trapezium. A key stoned construction would appear tend falling away from the observer.

Key stoned image of a Church

Keystone effect is not always bad
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Kicker: An additional side light or back light used to give a glow line around the head or side profile in studio photography. It is placed mostly in the plane of lens
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L l L :bigangel: l L L:smileys:L L :greendev: L L :mrgreen::mrgreen: L L L L L LLL
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Landscape: An image of Nature mostly having an aspect ratio where width is more than height.This is because our angle of view is more on horizontal plane and less on vertical pane. But it can be the other way too. Landscape should be predominantly Natural. Including some isolated houses or a road or a rail road etc. without affecting the natural feeling is OK. Since landscape needs maximum depth of field, a narrow aperture is always preferred. To compensate a slow shutter will be required. So if it is not a bright day of the time, a tripod is always essential.




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Leading Lines: Certain lines that mostly starts from the bottom line of an image which extend up to the main object of interest.These lines prevent eyes from wandering here and there and makes the journey of eyes effortless and fruitful. Such lines may not be real.


Leading lines take the eyes direct unto the main subject in the frame
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Lens: A lens is a device made of glass or similar material of high transparency and required refractive index which can either converge or diverge light rays. Lens is the heart of camera which collect all the visual information required for an image and pass it on to the sensor for recording. In cameras a group of lens work together to achieve different requirements. Focus, aperture, center of curvature, optical center, real and virtual images, magnification, power- all belong to the terminology related to lens optics.
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Light Box:Unlike a soft box, a light box is a box indeed. Soft box is a lighting system where as light box is the box where you place your object to be illumined uniformly with buffered light. It is used for product photography. Soft box is the light source where as light box is the receiver of light

To make one at home, please check this:

How to Create an Inexpensive Photography Lightbox: 15 steps

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Light painting:This is a creative non-conventional art form with light and camera as the means. We draw either by moving the light source like we move a brush over the canvas -here camera or more exactly the sensor is the canvas- or by moving the camera, the canvas equivalent here.
For light painting, mount the camera on a tripod, set the ISO to the lowest to minimize noise, use a narrow aperture, and slow shutter, like few seconds. Now use a thin beam of light as of torch or a burning candle or a LED light and move it in front of the camera and start writing in space, facing the camera, either random or a in a visualized pattern.By constant practice, you can limit writing within the field of view. You can use different color beams alternately to make brilliant color patterns.
Conversely the light point can be kept steady and looking through the viewfinder move your self along with the camera erratically or rhythmically always looking at the light source through the view finder.

In either case a light line image will be formed. By constant practice, you can be enormously creative. This kind of imaging is done in darkness. You can keep yourself not getting registered in the image by wearing black clothes and black gloves.

Capturing light tracks of vehicles at night is also a kind of light painting where you prepare the canvas and public do the painting inadvertently























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Low-Key Image: As against high key image, in low key image darkness is the master and light is the visitor. Mostly borders are illumined by light. The object appears projected out of darkness or immersed into the darkness. Low key lighting used to convey sad or gloomy or enigmatic contents. Low key images can be color or black & white.





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M m:sad anim:m:thumbsup:M Mm:love:m :bounce:m :cheers:m m :waiting:m:banghead:Mm
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Macro Lens/Macro photography: Macro lenses are used for extreme close ups of tiny bodies and organisms to show them life size or bigger. Unlike a tele zoom lens which captures a close up from distance, a macro lens captures the extreme close up from a close point with greater image quality and greater possible magnification.
Macro photography is also called macrography. Some call it more wisely photo macrography. For an image to be macro, its magnification(reproduction ratio) should be minimum 1:1(life size) or more.

Macro lenses are mostly of fixed focal lengths to give sharp results.So they are prime lenses. Macro zooms are available but yields comparatively poor quality images. They are available in focal lengths of 50mm, 60mm, 90mm, 100mm, 150mm and 180mm. Greater the focal length more the distance you can maintain with the object while you shoot, giving more working freedom and lesser risk of disturbing the object, if it is a living thing. With increase in focal length, depth of field will be diminished giving more impressive isolation.
*In very closeness lighting can be a problem.Ring flashes which is attatched to the front of the lens is frequently used in macro photography.
*Macro lenses have generally wide aperture letting more light enter into the sensor. But a wider aperture also means a shallow depth of field. Getting the different part of the object macrographed is also important. So care must be taken to see the main parts of the object appears sharp
*Macro lenses can focus up to infinity and can serve non-macro photography too. Many use this for portrait works, which yield excellent results.
*Macro lenses are available with image stabilization/vibration reduction features too.
*Generally macro lenses are costly. If you are ready to compromise on quality there are some cheaper alternatives like close up filters, extension tubes, bellows, reverse ring etc.

Macro Photography works well on flowers...



Even Tele-lens with macro option can give fairly good macro images

With a reverse ring attachment you can capture magnified images of tiny flowers.....
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Magnification: It is the term in optics used to compare the image size with the original size of the object. Mathematically it is the ratio of the image size to object size. If the image size double the size of object the magnification ratio is 2:1 or magnification is 2X. If the image size is smaller the ratio is less than 1. Then it is called de-magnification or some times minification.
Magnification depends upon the focusing distance and focal length. If the focusing distance is less, greater will be magnification; greater the focal length used, then also greater the magnification.
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Mask: Any piece of material that is used to cover a part of the lens to create the effect of multiple exposure.By alternately masking either half of the lens the same person can appear on either half of the same picture. Mask can be used to many other creative works as well as different kind of framings.
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Mirror Lock-up:This is a feature available in some models of camera. In Single Lens Reflex (SLR) cameras, what we see through the view finder is what the lens is going to see once the shutter is released. The lens focuses the image on a mirror placed at 45 degree in front of the shutter, screening the sensor and the image is reflected on to a penta prism. There the image suffers total internal reflection two times within the prism and emerges out to come out through the view finder.
When we press the shutter release button, the reflecting mirror rises, letting the focused image fall on the sensor behind and in the meanwhile the lifted mirror slams the pentaprism box above. This creates certain vibrations which would disturb the sensor while the image falls on it, leading to blurring of the image.
If image lock system is activated, while we click, the mirror moves up and slams prior to shutter release. There is a time lag between the rising of the mirror and release of the shutter so that the vibration caused by the mirror slam subsides.
While using mirror lock up, it is better to use a tripod and a remote trigger
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Monopod: A single legged camera support; here the photographers two legs work in unison to give the effect of a tripod, to some extent. It is less heavy and compact than tripod which also requires less ground space to locate. It is also called a unipod.