Help with understanding terms?

[Aedai]

Particularly f-stop. After reading the term on a page about exposure I looked into it and I'm still not sure I quite understand it.

I read that the lower the number is sharper your image is? Correct me if I'm wrong please.
What I'm confused about is how does it work? Is there a setting in the camera to play with, is it pre-setup in the lenses? I probably sound foolish to you more advanced photographers. /noob


Also in terms of camera settings... Should I set my ISO to auto or should I set it to 100 or does it depend on what kind of photograph I am taking?


And one last thing. I'm in an area that has a lot of waterfalls and steams and I love the "smooth" water effect and I'm not sure if my camera (Canon Rebel T3i) is capable of capturing one of those kind of images?


I apologize for being a complete noob!!

 

[ConradM]

http://www.thephotoforum.com/forum/...-forum/267492-info-those-new-photography.html

 

[ronlane]

Here is more information from Cambridge in Colour

 

[robbins.photo]

Particularly f-stop. After reading the term on a page about exposure I looked into it and I'm still not sure I quite understand it.

I read that the lower the number is sharper your image is? Correct me if I'm wrong please.
What I'm confused about is how does it work? Is there a setting in the camera to play with, is it pre-setup in the lenses? I probably sound foolish to you more advanced photographers. /noob


Also in terms of camera settings... Should I set my ISO to auto or should I set it to 100 or does it depend on what kind of photograph I am taking?


And one last thing. I'm in an area that has a lot of waterfalls and steams and I love the "smooth" water effect and I'm not sure if my camera (Canon Rebel T3i) is capable of capturing one of those kind of images?


I apologize for being a complete noob!!

No worries, we all start somewhere. I did a posting on this already today that covers some of the basics so I hope you won't mind if I just give you a link to that one.. it's kind of wordy.. lol.

http://www.thephotoforum.com/forum/welcomes-introductions/359688-hi-im-new-kid-block.html

Post #3.

Oh, and not sure if I put this in the other post so it might help to know that F-Stop refers to your aperture setting - the higher your F-stop, the more your "stopping down" the lens and the less light it allows to pass through. Might seem backwards but F-stops are actually fractions, so the lower the number the wider the opening of the lens and therefore the more light you have to work with.

 

[Designer]

Particularly f-stop. After reading the term on a page about exposure I looked into it and I'm still not sure I quite understand it.

I read that the lower the number is sharper your image is? Correct me if I'm wrong please.
What I'm confused about is how does it work? Is there a setting in the camera to play with, is it pre-setup in the lenses? I probably sound foolish to you more advanced photographers. /noob


Also in terms of camera settings... Should I set my ISO to auto or should I set it to 100 or does it depend on what kind of photograph I am taking?


And one last thing. I'm in an area that has a lot of waterfalls and steams and I love the "smooth" water effect and I'm not sure if my camera (Canon Rebel T3i) is capable of capturing one of those kind of images?


I apologize for being a complete noob!!

Hey, don't worry about asking questions. Most of us are happy to answer.

Robbins handled the aperture question.

Probably most of the time for beginners let the camera select the ISO by putting it on "auto". In time you will learn when to change it and to what amount.

To get the "smooth water" shots, you need to have a longer shutter opening i.e.: "slower shutter". So now how to make your camera use a slower shutter? If you have a tripod, you can stop down the aperture to a very small opening (f1:22, or f1:32, for instance) and see if the shutter speed will go to 1/15 of a second or 1/20 of a second for instance, or even slower if you want the water smoother.

Set the self timer so your finger stays off the camera, and get a fairly long exposure of the water. If you can't get the shutter to slow down enough, you might have to purchase a neutral density (ND) filter to put on the front of your lens. This is simply a filter that filters out the brightness of the light so the shutter will stay open longer.

BTW: this is when you do NOT want the camera to "auto" select the ISO. Keep the ISO at 100 for smooth water.

 

[MOREGONE]

The F stop is an equation or ratio of inner diameter of the lens in relation to the focal length

So if you had a 50mm lens with f1 it would actually mean the aperture, inside diameter would be equal to the 50mm length or 1:1. When you have F2, it is 1:2 or 1/2 the size of the focal length. When you have a 50mm f1.8 it is 50/1.8=27.77mm


100/f2.8 = 35.71mm
200/f5.6 = 35.71mm

See how the focal length doubled, but so did the fstop, so the diameter is still the same

Hope this helps.

 

[WayneF]

Particularly f-stop. After reading the term on a page about exposure I looked into it and I'm still not sure I quite understand it.

I read that the lower the number is sharper your image is? Correct me if I'm wrong please.
What I'm confused about is how does it work? Is there a setting in the camera to play with, is it pre-setup in the lenses? I probably sound foolish to you more advanced photographers. /noob


Also in terms of camera settings... Should I set my ISO to auto or should I set it to 100 or does it depend on what kind of photograph I am taking?


And one last thing. I'm in an area that has a lot of waterfalls and steams and I love the "smooth" water effect and I'm not sure if my camera (Canon Rebel T3i) is capable of capturing one of those kind of images?


I apologize for being a complete noob!!

All beginners need this book:
Understanding Exposure, 3rd Edition: How to Shoot Great Photographs with Any Camera: Bryan Peterson: 0884798534707: Amazon.com: Books

At this point, it is the best $15 you can spend on photography. It is popular in local libraries too, good chance it is there.

Its subject Exposure is about aperture (f/stop), and shutter speed, and ISO, and when and why you would choose different values of them.
It is an easy read, lots of pictures, not deep - just a good introduction of basics to get beginners started right. It is the LEAST we should know, and is of concern in every picture we will ever take.

Lower numbered f/stop is not necessarily sharper... There are different definitions. Best general values are normally more in the middle, like f/5.6 or f/8.
Yes, high numbers like f/16 do increase diffraction, the opposite of sharp, but higher does give more depth of field (sharper at a distance range from exact point of focus).

For a smooth water effect, choose a slow shutter speed, like maybe 1/10 second, maybe slower.

Read the book.

 

[LinusR]

The information that conrad supplied was priceless, really helped me

 

[CarolynB28]

The best advice I can give is to research all three exposure settings with your camera in hand until they do make sense. Research, practice, evaluate your photos and learn from each experience. One day it will all click! As with the waterfall, absolutely! But knowledge in light and using manual should be learned first.

 

[CarolynB28]

Ps. Every setting depends on every shot! The lighting, the situation, the look and style you desire. Don't ever think that a one setting fits all, because it never will. I only use auto focus (most of the time) everything else (wb, focus points, shutter speed, aperture, ISO, ect) is always manual because I would rather be completely in control. And this will all take time to understand, so don't worry that you use some things in auto while you are learning the others.

 

[KmH]

This 'sticky' thread is at the tip of the Beginners' forum - http://www.thephotoforum.com/forum/...rum/167288-camera-terms-acronyms-dummies.html

To clear up a couple of points regarding lens aperture and f-stops:

f/x is a fraction, or a ratio of the lens focal length to the lens aperture width.
Put another way, the f stands for the focal length of the lens being used, and the number is what fraction of the lens focal length the lens aperture is.
So if you use a 100 mm lens and the lens is set to f/2, the fraction is - 100 mm/2 - or 100 mm divided by 2 = 50 mm.
50 mm is how wide the lens aperture is.
At f/4 using a 100 mm lens the lens aperture is 25 mm wide.
Note: Being fractions - f/2 is a bigger number than f/8 is - like 1/2 a pie is a bigger slice of pie than a 1/8 slice of a pie is.

A lens with a 50 mm focal length set to f/@ will have a 25 mm wide lens aperture - 50 mm / 2 = 25 mm.
At f/4 using a 50 mm lens the lens aperture is 12.5 mm wide.

As a lens is stopped down the focus depth-of-field gets deeper but focus does not always get sharper. In large part it depends on the optical quality of the glass lens elements in the lens.
At smaller lens apertures an optical aberration known as diffraction can also cause focus to lose sharpness.
Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks
Understanding Camera Lenses
Understanding Depth of Field in Photography

What is a Stop
A 'stop' is a doubling (2x) or a halving (0.5x) of the amount of light and a stop is a fundamental photography concept.
A stop change in exposure can also apply to shutter speed and ISO.

Since exposure is a triad of adjustments (shutter speed, ISO, lens aperture) you can change 1, 2 or all 3 of the triad settings.

If you want 1 more stop of exposure (brighter) you can adjust just one of the 3 by 1 more stop.
Or, you can change 2 of the 3 by 1/2 more stop each for a net gain of 1 stop of exposure.
Or, you can adjust all 3 by 1/3 more stop for a net gain of 1 stop of exposure.

You can also change the triad of settings and have no change in the exposure.
If you change 1 of the 3 settings by 1 stop more exposure and change a 2nd setting by 1 stop less exposure the net change is zero.
Suppose you subtracted a stop of shutter speed to help stop subject motion, you could add a stop of lens aperture to keep the exposure the same. However, adding a stop of aperture will also affect the total DoF by a small amount. So, if you don't want the DoF to change you would add a stop of ISO instead, however, adding a stop of ISO will increase by some amount the image noise in the photo.

Note: DSLR cameras are set by default to adjust the exposure settings in 1/3 stop increments.
Most DSLR cameras let you change that to 1/2 stop or 1 stop increments.
However, the advantage of 1/3 stop step increments is more precise control of exposure.

 

[Civchic]

All this technical stuff is, of course, totally correct. And for a brand new, non-technical person, a little scary. The best way to learn what aperture, shutter speed and ISO do is to practice, of course, so you see what happens. But for a visual learner to understand WHY -

You have a bucket with a lid and a hose to fill it up. The light to make your picture is the water coming out of the hose. Your picture is the water in the bucket. On the lid is a hole with a flap over it. The hole is your aperture - a small hole lets in a little bit of light, a big hole lets in a lot of light. So if you want your picture made quickly, it helps to have a BIG hole. If you want a longer exposure, making your picture with the moving water, for instance, you want a little tiny hole so the bucket fills slower. Now the flap over the hole is your shutter. If you open it very briefly, you're going to get a tiny bit of water in quickly (freeze motion) and if you hold it open, you're going to have a longer exposure (blur).

Your flow rate from the hose is your ISO. Turn it up, you get more water coming out of the hose faster, which helps if you can't get your flap big enough and your hole wide enough for the situation, but can sometimes cause a bit of splash and mess (image noise).

Combine these three things, water flow (ISO speed), aperture (size of hole), and shutter speed (how long you open the flap over the hole) and you make an image (fill your bucket to the correct level). There are multiple combinations of the three things to achieve what you want, and learning how each one works for you is photography!

 

[astroNikon]

This stuff was confusing to me when I first learned it.

As mentioned it's easier to test things with the camera to understand it.

If youtake a photo in AUTO look at what the settings were.
So, for example if a shot was
aperture f/5.6
Shutter 1/250
ISO 100

Then change the aperture to say 6.3 .. what happens (gets darker)
then change to 7.1 .. darker still ...
f/8 .. darker still
this is occurring because the aperture opening is getting smaller

Then try the other way .. f/5.6 ... f/4 ... it gets brighter and brighter because the opening is getting larger letting more light in.

NOW ... aperture also control Depth of Field ... which we'll ignore for this.

If you set aperture back to f/5.6 ... now you can play with the Shutter Speed.

Same thing .. increase shutter speed to say 1/500, up to say 1/1250 .. it gets darker as you increase shutter speed.
and as you slow it down from 1/250 to 1/60 it gets brighter. This is because it is letting more light in as in more time to let light in.

ISO .. same thing .. increase it slowly up to 800 and the image will get brighter because the sensor will become more sensitive to the light itself.


So you are basically trying to find the happy medium between all 3 ISO, Shutter and Aperture for the correct exposure ..
After you get that then there's alot to learn of how each 3 can affect the same image in varying ways.

Good Luck



edit: oops .. CivicChic basically said the same thing I did but was faster at posting .. lol .. that's been happening alot lately