Aperture and DOF

[Hertz van Rental]

Actually I never bothered working it out.
With LF just sopped down a bit and used a mag on the glass to check it visually then shoot a polaroid and check it that way (calculating DoF if you are using Scheimpflug is a *****).
Most 35mm film camera lenses (and some MF lenses) have an approximate DoF scale on them anyway. You can estimate how much DoF you need by focussing on the nearest point you want, and the furthest, and checking the difference using the DoF scale.
Remeber that for landscape it is best to optimise. Normally you focus on something quite far away - if you stop right down for max DoF you are technically focusing some of the image beyond infinity. To maximise DoF focus use the hyperfocal distance (or put the infinity marking against your aperture on the DoF scale).

 

[etaf]

i used to use the marks on the lens evertime i took landscapes etc - however, the canon kit i purchased in 1997 nolonger had these markings 28-105mm, 28-80mm, 50mm lenses - so i did not know how to set that hyperfocal distant in the field and had to guess.
now on my pro1 i have no idea how to do it.
anyone have a rule of thumb when you are on a walk about and want a high DoF where to focus

 

[ksmattfish]

Most 35mm film camera lenses (and some MF lenses) have an approximate DoF scale on them anyway.

Not if it was made by Nikon, Canon, Pentax, Minolta, etc... since about 1990. Go into a camera store and see how many 35mm lenses have a DOF scale these days. I can understand not having one on a zoom lens, but they aren't even putting them on the prime lenses these days. I don't know why; must save them five cents.

 

[ksmattfish]

anyone have a rule of thumb when you are on a walk about and want a high DoF where to focus

I keep a little notebook that has the hyperfocal distances for my lenses without DOF scales. For some lenses I've actually written out a complete chart for the marked focus distances and apertures. I need to get a palm pilot or something and put it all in there.

Somewhere out there I've also seen a site where you can plug in the stats of your lenses, and it will make a printable template that you can print out and assemble. It's a small disc that simulates how a DOF scale on a prime lens works.

 

[Hertz van Rental]

Not if it was made by Nikon, Canon, Pentax, Minolta, etc... since about 1990. Go into a camera store and see how many 35mm lenses have a DOF scale these days. I can understand not having one on a zoom lens, but they aren't even putting them on the prime lenses these days. I don't know why; must save them five cents.

Eeek! Shows you how often I buy lenses. But I guess if you got good ones and you look after them then you don't need to.
I guess they did 'market research' and found people never used the scales. What will be the next thing to go?

 

[etaf]

found a site
http://www.johnhendry.com/gadget/hf.php
however, i guess the limitations of my point and shot appear now.
the manual focus gadge only shows 5m then infinity so trying to set 104ft or 50ft will be trail and error - so i guess i could go out and play with some test shots

i guess the next question is how this works with digital - if i use the actual focal length does the aperture still apply or do i need to use the FoV factor

thanks

 

[ksmattfish]

What will be the next thing to go?

Well, the thing that has already gone that ticks me off is manual focus assist, like a split ring or something.

The whole thing about DOF scales is that it seems to me that they could build it into the software in all these fancy electronic cameras (digital and film). Just like the high end flashes show you the general effective range, they could display effective DOF in the viewfinder or something.

 

[SLOShooter]

Tip: IF your camera has a DOF preview button, don't hit it while you'er set at your desired aperature. Start off at a large aperature, hit the DOF preview button, then stop it down slowly till you reach your desired aperature. This lets your eye adjust to the lowering light levels and you'll see the DOF change better.

 

[ksmattfish]

Tip: IF your camera has a DOF preview button, don't hit it while you'er set at your desired aperature. Start off at a large aperature, hit the DOF preview button, then stop it down slowly till you reach your desired aperature. This lets your eye adjust to the lowering light levels and you'll see the DOF change better.

That is a good tip, and of course with digital, if you have a camera that lets you zoom in on a photo after it's taken, you could check DOF then, and reshoot if necessary.

 

[wharrison]

Mountainlander:

I've posted this elsewhere (photo.net) and thought it might be a little helpful.

Sorry for the long discussion, but I do hope that you and others will find it useful. There's more to come.


There are really only three factors governing the subject of depth of field for 35mm cameras specifically and other film formats generally.

Hopefully, the following discussion will boil them down for you, but before we get into that topic, there are a few basics you will need to know.

1. First of all the eye doesn't see so well - especially under available or poor lighting conditions. The general consensus is that the human eye can see a circle as a dot, if that circle has a diameter of l/100 of an inch or less on an 8 X 12 (or sometimes 7 X 10) enlargement held approximate ten inches away.

That means that in order for the circle of confusion (it's correct name) to be see as a dot on the above standards, that circle of confusion has to be 1/800 of an inch in diameter on the negative.

Thus - the need for critical focusing = especially when shooting at wide aperatures under available light conditions. The problem of critical focusing under such conditions has been solved in various ways - i.e. the use of rangefinder cameras or using high aperature lenses on SLR cameras, i.e. a 50mm F/1.4 lens versus a 50mm F/2.0 lens.

Obviously, if you're slightly out of focus with a 35mm F/2.0 lens on a 35mm SLR camera - which can easily happen especially under low light conditions - you may start off with a large "circle of confusion" on the negative or slide. The more you enlarge an unsharp image (negative or slide), the greater the unsharpness will be noted in the final enlargement or projected image.

For that reason, discussions of depth of field cannot be separated from the issue(s) of critical focusing - again and especially under available light conditions.

If you wish to check this out, you can simply put on a wide angle lens on your SLR, turn off the lights in a room to make it semi-dark - like in the late evening and then walk about 12 - 15 away from the subject or point of focus. With an SLR camera, you may find it very difficult to be certain of accurate focus under these conditions. For example, you may find that you're actually focused at infinity when in reality the subject is only 12 feet away.

Why? For one thing, our eyes don't see to well; for another, a wide angle lens on a 35mm SLR camera will make the image appear smaller and/or further away, thus making the "details" more difficult to see. Under such conditions a split image focusing screen can be very helpful. Depending upon the type of rangefinder camera, a rangefinder camera will be able to focus both accurately and rapidly under nearly all available light conditions using lenses from 21mm or lower to up to either a 90mm focal length or a 135mm focal length. An old Leica M-3 would be a good example.

To give you another example, my 90mm Summicron F/2.0 focused at the closest distance (about 3.5 feet) and using the lens wide open (F/2.0) has exactly 3/4 of an inch of depth of field - which is less than the distance from the tip of most people's noses to their eyes. So what's the point of focus to be and how accurate is it going to be? are useful questions to ponder and/or resolve.

Now that you have, hopefully, understood this discussion - let's go onward to the two important factors regarding depth of field and then we'll tackle the third and most important factor.

2. From a technical stand point, depth of field is dependent upon only two factors (1) the aperture of the lens and (2) the ratio of reproduction. Or to put it in another way, all lenses will exhibit exactly the same depth of field if they are used at the same aperture and at the same ratio of reproduction.

Verification of this basic factor can be found in some of the older and better books on photography - namely - most editions of The Pentax Way or The Leica Way, etc. In the back of these books, you find a series of depth of field tables, especially for macro work or photomacragraphy.

In short, a 50mm macro lens and a 100mm macro lens set at F/4.0 and at a reproduction ratio of 1:2 will have exactly the same depth of field.

Obviously, this may bring up - in your mind - the topic of what is meant by the "ratio of reproduction".

The ratio of reproduction represented by the 1:2 - above - indicates - first - your film size, or 24mm X 36mm or approximately 1 X 1.5 inches. The second number (2) indicates that the area that your lens is covering - in this case it is twice as large as your negative or 2 X 3 (1 x 1.5) X 2. Therefore, a reproduction ratio of 1:10 would indicate that your lens is covering an area of 10 x 15 inches. And so on and so forth.

Therefore, you should now realize that the only reason that wide angle lenses "appear" to have a greater depth of field to most people is that they are simply standing in the same place, but changing their normal lens (50mm - for example) and putting a 28mm lens on the camera. Obviously, you have automatically changed the ratio of reproduction by simply including a far wider area with the 28mm lens.

However, if you would change back to the 50mm lens and then walk backwards to include the same area of coverage as your 28mm lens, you would end up with exactly the same depth of field.

Obviously, you should now understand the statement made in the third sentence.

One of the most unfortunate aspects of photography is that you (and many others) will encounter a host of explanations for various kinds of photographic techniques, procedures, etc. and equally unfortunate much of it will amount to little more than "verbage" or outright "BS".

One good example that I well remember came from reading Ansel Adams explanation of his famous photograph of the moon rise taken somewhere in the southwest - New Mexico, I believe. Sorry, I can't remember the exact title given to this wonderful photograph.

In reading his discussion of how this photograph was taken, Adams goes through all sorts of language contortions about the exposure value of moonlight, how he calculated the "exposure" of this moonlight, etc., etc., etc. And then his finishes the discussion by stating that he made one or several "calculated safety shot(s)."

When I originally read his discussion, I laughed out loud at his "calculated safety shot(s). What a "BS'er" I thought and still do. Why can't this man use the same term that everyone else does?

A rather highbrow term for the simple matter of "bracketing."

Obviously, Ansel Adams was a good photographer, but he was also, IMHO, rather pretentious and verbose. Somewhere there is another example of Ansel's verbosity, you'll find it in a discussion between Ansel Adams and Peter Stockpole who wanted to join the F/64 group and who was fired for using a "miniature camera" on the job. The "miniature" camera in question was an early screw mount Leica. Sorry, I can't remember the title of the book, but I think it was in a book written by Peter Stockpole about his photographic experiences and/or working on photographing the building of the Golden Gate brige.

At the beginning of this discussion, I indicated that there were three factors concerning depth of field and that the third factor was the most important.

Well, what is the third factor?

Aesthetics - pure and simple.

At this point, you must learn to merely keep in mind the basic principles that I've discussed (clearly, I hope) above and concentrate more on what you wish to convey artistically.

Years ago, when I was at New Salem State Park - near Springfield, IL - the park had an interesting event going on - during the early winter.

One of the events being "exhibited" were a small group of women quilting in one of the log cabins. I approach one of the women and began discussing whether or not she had read the book or seen the play of nearly the same name: The Quilters: Women and Domestic Art. (I highly recommend both reading the book and/or seeing the play.) Mostly, because I wanted to convey the information to her and secondly it was a means of breaking the "ice" when photographing people.

While I was discussing the book and the play, I took an incident light meter reading and set my shutter speed and lens opening accordingly. I can't remember the shutter speed, but the aperture was set at F/2.0 since I was using Kodachrome 64 slide film, my Leica M-4 and the 50mm Summicron.

I deliberately focused on the women's eyeglass frame, composed and tripped the shutter. Turn out superb!! Again IMHO!! ;>)

Generally, most people might have focused on her eyelashes or her eyeball, but I chose the eyeglass frames instead because I wanted them to be in sharp focus. And more importantly, because I deliberately wanted to soften the lines in her somewhat aged skin, i.e. soften the wrinkles in other words. In my head, I already knew that the depth of field was going to be rather, if not very, shallow.

In short, I simply made quick use of my technical knowledge and previous experiences and use them to determined what kind of aesthetic results I wanted.

Obviously, now that you know something more about depth of field, you are going to have to do some experimenting with different focal lengths and/or apertures to see what kind of results you will obtain and then use the results to narrow them down to what you wish to obtain. It may take some time and practice, but that's the fun and sometimes fustrating part of photography.

My best wishes in your endeavors and I do hope this not so brief discussion clears things up.

Bill

 

[wharrison]

Mountainlander:

A shorter and second round of discussion.

If you link to the site listed below, you'll find a good example of what I was previously discussing. Once you arrive on the scene - so to speak - scroll down until you find the photograph - on the right side - titled "Premiere at La Scala, Milan," 1933 read the notes about the photograph or the whole article and then scroll all the way down and read the last paragraph and take note!!!

If you wish to explore this photographer a little further - Eisenstaedt was one of the original photographers for Life magazine - there is an excellent book entitled: "The Eye of Eisenstaedt". Unforuntately, it is out of print, but may be found at or through the inter-library loan system at your local public library.

This book is an excellent "arm chair read" - where you can curl up on a comfortable place, sip on some coffee, tea, wine or some other beverage and read and learn in an enjoyable manner. The book combines a little autobiography, good basic, but small, discussions on (his) photography, etc., but most important is is a book on how to see photographically.

http://artscenecal.com/ArticlesFile/Archive/Articles1997/Articles0397/AEisenstaedt.html

Again, I hope that this added tidbit is useful in your endeavors.

Best regards, Bill

 

[wharrison]

Mountainlander:

Now - here's some more information, which I also hope you will find very useful.

Decades ago, I taught "Architectural Photography" for a number of years at Illinois Central College in East Peoria, IL.. Since the course was taught under the auspices of the Architectural Department, it was basically a course in good, 35mm photography with an architectural emphasis, especially as none of the students had or could afford a 4 X 5 view camera with one or several lenses.

Somewhat surprising to me at the time was the fact that many of my students also had difficulty in understanding depth of field. From that point onward, I thought and still believe that the best way to understand and work with depth of field is to approach photography with a sense of aesthetics first and then make use of various techniques to (hopefully) achieve the results you wish to put on film. A point which will lead us back to a further discussion of Alfred Eisenstaedt's photograph of the young society lady at the La Scale Opera house decades ago.

Using the SWAG method ("scientific" wild ass guess), I suspect that Eisenstaedt took this photograph with a 35mm lens on his screw mount Leica camera. One of the reasons why I choose this photograph was to - obviously - introduce you to this original Life photographer and, of course, to show you this particular photograph as an example of using a sense of aesthetics and then using various techniques to achieve the results you want.

As Eisenstaedt correctly states, the young society lady makes this photograph 'come alive'!! Without her and, especially, her expression, the photograph would have been dead in the water. The viewer's eye is first directed to her presence and expression and then wanders around to the rest of the photograph. It is a good example of how aesthetics play the defining role in determining depth of field - as it well should be.

Equally obvious is the fact that had Eisenstaedt attempted to create a greater depth of field, this photograph would have been dead in the water as well. Why? Well, any time that you make use of a smaller aperture you have to have a corresponding increase in exposure time in order to obtain a correct exposure. Had he attempted to have everything in focus from foreground to background, he would have had to make use of a rather small lens opening and his exposure - under these available light conditions - would have been incredibly long. Since the point of the photograph was to rapidly record the young's expression in the foreground, the point of focus had to be on her face. So now we are back to the starting point of my first response, i.e. accurate focus!

Another example to share.

Several decades ago, I traveled to Alameda, California to visit my cousin and his bride to be. Since Ken was still teaching at the local community college during the week, I took off to downtown San Francisco and begin to wander around one of the more famous downtown squares to see what I could photograph.

While visiting one of the more famous downtown gathering places, I immediately spied two older ladies who were dressed in their Sunday best; who were also sitting close together; and chatting away in a rather delightful and animated manner. I knewthat if I pointed my camera at them that they might immediately recognize that I was about to take their photograph to which they might object and/or which might have made them both self-conscious. I also noted the fact that these women - like most - didn't mind being physically close to one another, but for some reason most of us men seem to need to have some "space" between ourselves and another man.

Since I had the 90mm Summicron F/2.0 on my Leica M-4 camera, I knew that it had a limited depth of field in comparison to my 50mm Summicron. From my previous experiences, I knew that using a lens opening of F/8.0 that I would have slightly more than enough depth of field to cover a little more from foreground to a little more in the background of the two ladies sitting on the park bench. I also suspected that at this aperture I had enough depth of field to cover any possible error in focusing.

I quickly focused on an area that was a similar distance from the two ladies; took a meter reading to determine the shutter speed for an aperture of F/8.0; set the lens opening and shutter speed accordingly, swung around; rapidly composed the photograph; and tripped the shutter.

Even though the Leica's shutter is extremely quiet and soft and I made no 'noise' - ;>) - to bring attention to myself; the two elderly ladies must have suspected that they were being photographed and immediately asked me to desist and not take anymore photographs. Obviously, I responded by simply smiling and acknowledged their wishes. Why? Because I had simply achieved the results I wanted.

By the way, I was using Plus-X B & W 35mm film and developed the negatives in Microdol-X at a 1:3 ratio to give me a long tonal range and enlarged it - easily - up to a 16 x 20 print using a used Leitz Valoy II enlarger that I had purchased used.

Here again, we are simply making use of a sense of aesthetics and then subjecting our technical knowledge and experiences to achieve the results that we want.

You now know - or should know - that wider apertures, such as F/2.0 or F/4.0 will provide you with a relatively shallow depth of field; that moderate apertures, such as F/5.6 or F/8.0 will provide you with a moderate depth of field; and that smaller apertures, such as F/11 or F/22 will provide you with a greater depth of field.

You now know - or should know - that if you change from a normal, i.e. 50mm lens to a wider angle lens, i.e. a 35mm or a 28mm lens, you will cover a wider area or angle of view, which will make everything seem to be smaller and further away, and that because of the greater ratio of reproduction, i.e. greater angle of view, you will correspondingly increase your depth of field using the same vantage point.

You also now know - or should know - that if you change from a normal, i.e. 50mms lens to a narrow angle lens, i.e. a 90mm, a 135mm or a 200mm lens, etc., you will cover a narrower area or angle of view and thus make everything appear to be closer and larger and that because of the smaller ratio of reproduction or lesser angle of view, you will correspondingly decrease your depth of field using the same vantage point.

You also now know - or should know - that each of your lenses will provide you with a different angle of view, if you stand in the same position and that if you change positions your lenses, will give you a different perspective in achieving your photographic projects

You also now know - or should know - that in the area of photomicrography - your lenses will provide you with exactly the same depth of field - provided you are (1) covering the same ratio of reproduction and (2) are using the same lens opening.

You also now know - or should know - that if you change your lenses and your position from the subject so that each of the lenses will cover the same area, you will not only achieve a different perspective, but that you will have exactly the depth of field, if you make use of the same aperture.

Except in the field of photomicrography, you will or may not need to critically address the matter of depth of field. You will or should, however, keep all of the above "technical" factors in mind when you photograph and then, as I will state - once again-* let your sense of aesthetics determine the various photographic techniques and/or lenses, etc., etc. to be used to produce the results intended.

Since you paint, you realize that you would not use a broad brush and/or a broad brush stroke to achieve fine detail in your painting. The same artistic principles hold forth in photography as well.

Again, my best wishes in your endeavors.

Bill

 

[wharrison]

Mountainlander:

Now - here's some more information, which I also hope you will find very useful.

Decades ago, I taught "Architectural Photography" for a number of years at Illinois Central College in East Peoria, IL.. Since the course was taught under the auspices of the Architectural Department, it was basically a course in good, 35mm photography with an architectural emphasis, especially as none of the students had or could afford a 4 X 5 view camera with one or several lenses.

Somewhat surprising to me at the time was the fact that many of my students also had difficulty in understanding depth of field. From that point onward, I thought and still believe that the best way to understand and work with depth of field is to approach photography with a sense of aesthetics first and then make use of various techniques to (hopefully) achieve the results you wish to put on film. A point which will lead us back to a further discussion of Alfred Eisenstaedt's photograph of the young society lady at the La Scale Opera house decades ago.

Using the SWAG method ("scientific" wild ass guess), I suspect that Eisenstaedt took this photograph with a 35mm lens on his screw mount Leica camera. One of the reasons why I choose this photograph was to - obviously - introduce you to this original Life photographer and, of course, to show you this particular photograph as an example of using a sense of aesthetics and then using various techniques to achieve the results you want.

As Eisenstaedt correctly states, the young society lady makes this photograph 'come alive'!! Without her and, especially, her expression, the photograph would have been dead in the water. The viewer's eye is first directed to her presence and expression and then wanders around to the rest of the photograph. It is a good example of how aesthetics play the defining role in determining depth of field - as it well should be.

Equally obvious is the fact that had Eisenstaedt attempted to create a greater depth of field, this photograph would have been dead in the water as well. Why? Well, any time that you make use of a smaller aperture you have to have a corresponding increase in exposure time in order to obtain a correct exposure. Had he attempted to have everything in focus from foreground to background, he would have had to make use of a rather small lens opening and his exposure - under these available light conditions - would have been incredibly long. Since the point of the photograph was to rapidly record the young's expression in the foreground, the point of focus had to be on her face. So now we are back to the starting point of my first response, i.e. accurate focus!

Another example to share.

Several decades ago, I traveled to Alameda, California to visit my cousin and his bride to be. Since Ken was still teaching at the local community college during the week, I took off to downtown San Francisco and begin to wander around one of the more famous downtown squares to see what I could photograph.

While visiting one of the more famous downtown gathering places, I immediately spied two older ladies who were dressed in their Sunday best; who were also sitting close together; and chatting away in a rather delightful and animated manner. I knewthat if I pointed my camera at them that they might immediately recognize that I was about to take their photograph to which they might object and/or which might have made them both self-conscious. I also noted the fact that these women - like most - didn't mind being physically close to one another, but for some reason most of us men seem to need to have some "space" between ourselves and another man.

Since I had the 90mm Summicron F/2.0 on my Leica M-4 camera, I knew that it had a limited depth of field in comparison to my 50mm Summicron. From my previous experiences, I knew that using a lens opening of F/8.0 that I would have slightly more than enough depth of field to cover a little more from foreground to a little more in the background of the two ladies sitting on the park bench. I also suspected that at this aperture I had enough depth of field to cover any possible error in focusing.

I quickly focused on an area that was a similar distance from the two ladies; took a meter reading to determine the shutter speed for an aperture of F/8.0; set the lens opening and shutter speed accordingly, swung around; rapidly composed the photograph; and tripped the shutter.

Even though the Leica's shutter is extremely quiet and soft and I made no 'noise' - ;>) - to bring attention to myself; the two elderly ladies must have suspected that they were being photographed and immediately asked me to desist and not take anymore photographs. Obviously, I responded by simply smiling and acknowledged their wishes. Why? Because I had simply achieved the results I wanted.

By the way, I was using Plus-X B & W 35mm film and developed the negatives in Microdol-X at a 1:3 ratio to give me a long tonal range and enlarged it - easily - up to a 16 x 20 print using a used Leitz Valoy II enlarger that I had purchased used.

Here again, we are simply making use of a sense of aesthetics and then subjecting our technical knowledge and experiences to achieve the results that we want.

You now know - or should know - that wider apertures, such as F/2.0 or F/4.0 will provide you with a relatively shallow depth of field; that moderate apertures, such as F/5.6 or F/8.0 will provide you with a moderate depth of field; and that smaller apertures, such as F/11 or F/22 will provide you with a greater depth of field.

You now know - or should know - that if you change from a normal, i.e. 50mm lens to a wider angle lens, i.e. a 35mm or a 28mm lens, you will cover a wider area or angle of view, which will make everything seem to be smaller and further away, and that because of the greater ratio of reproduction, i.e. greater angle of view, you will correspondingly increase your depth of field using the same vantage point.

You also now know - or should know - that if you change from a normal, i.e. 50mms lens to a narrow angle lens, i.e. a 90mm, a 135mm or a 200mm lens, etc., you will cover a narrower area or angle of view and thus make everything appear to be closer and larger and that because of the smaller ratio of reproduction or lesser angle of view, you will correspondingly decrease your depth of field using the same vantage point.

You also now know - or should know - that each of your lenses will provide you with a different angle of view, if you stand in the same position and that if you change positions your lenses, will give you a different perspective in achieving your photographic projects

You also now know - or should know - that in the area of photomicrography - your lenses will provide you with exactly the same depth of field - provided you are (1) covering the same ratio of reproduction and (2) are using the same lens opening.

You also now know - or should know - that if you change your lenses and your position from the subject so that each of the lenses will cover the same area, you will not only achieve a different perspective, but that you will have exactly the depth of field, if you make use of the same aperture.

Except in the field of photomicrography, you will or may not need to critically address the matter of depth of field. You will or should, however, keep all of the above "technical" factors in mind when you photograph and then, as I will state - once again-* let your sense of aesthetics determine the various photographic techniques and/or lenses, etc., etc. to be used to produce the results intended.

Again, my best wishes in your endeavors.

Bill

 

[Nagala]

This link may help.

http://www.dofmaster.com/dofjs.html

 

[ShutteredEye]

Whoah!! Thanks for all the reading guys!