Depth Of Field Preview Button

[MajaMolly]

Depth Of Field Preview Button - do you use it? I seriously can't figure out how it works. I've read the manual (Nikon) it says where it is, but not how to use it - other than pressing it.

[Manfred M]

You've figured it out. What the DoF preview button does is stops down your lens so that you can see the effect of stopping down your lens does. If you look through the viewfinder, you will notice everything has darkened up, especially if you are shooting at a high f-stop (f/16, for instance). This is something that the old film shooters used all the time and is a bit of a legacy feature.

I haven't tried to see what happens in live view, but I suspect that things may be a bit brighter. You should be able to zoom in using the controls to examine the image, but frankly, unless you are shooting off a triipod, this is really hard to do because you are likely moving the camera around.

While I used it all the time with film, I use a totally different technique in digital. I take a test shot and then magnify the resultant image on the screen to see how the focus and DoF worked out in the shot. It works fine for landscapes and other scenes that are relatively static.

[MajaMolly]

Thank you!!! I did notice that the view changed a bit, but wasn't exactly sure what I was suppose to be looking for.

[John Morton]

Depth of Field Preview is something that was on even those old completely manual film cameras. Basically, a camera lens is kept open at its widest aperture until the shutter is tripped to take a photograph. The camera's system(s) themselves determine the correct exposure from information sent by the lens regarding where the aperture is set.

Depth of field varies with the size of the lens aperture. Old style film camera lenses had pairs of aperture numbers inscribed on either side of the lens focus mark, where the distance scale was, so that one could focus the camera at "distance Y" and set the aperture, then look at the inscribed numbers and say "At f/whatever, everything from distance X to distance Z swill be in focus."

Digital lenses don't seem to have those inscribed paired aperture numbers anymore.

Looking through the lens, one could also manually close the aperture from its largest setting to whatever one had set the lens aperture to be for an exposure. This allows one to actually see what is and is not in focus; but not very well, since there is less light coming through the lens and that makes it a little hard to actually see where what is in focus begins and ends.

Short answer: pressing the depth of field preview button manually closes the lens aperture to the opening it is set for, allowing one to actually see what is and is not in focus at that setting.

Oh - lenses also use to come with little booklets that had, among other things, tables that listed distances along one side, apertures along the other, and which showed in the table EXACTLY where the closest and farthest thing in focus was for each distance/aperture pairing.

{I see Manfred has already answered you as I was typing}

[Mike Buckley]

You may not have the time for whatever reason to take the shot, review the depth of field afterwards in the LCD and perhaps retake the shot. If that's the case, your camera may allow you to automatically bracket the aperture setting for 3 or more shots, each at an incrementally different aperture.

[MajaMolly]

Depth of Field Preview is something that was on even those old completely manual film cameras. Basically, a camera lens is kept open at its widest aperture until the shutter is tripped to take a photograph. The camera's system(s) themselves determine the correct exposure from information sent by the lens regarding where the aperture is set.

Depth of field varies with the size of the lens aperture. Old style film camera lenses had pairs of aperture numbers inscribed on either side of the lens focus mark, where the distance scale was, so that one could focus the camera at "distance Y" and set the aperture, then look at the inscribed numbers and say "At f/whatever, everything from distance X to distance Z swill be in focus."

Digital lenses don't seem to have those inscribed paired aperture numbers anymore.

Looking through the lens, one could also manually close the aperture from its largest setting to whatever one had set the lens aperture to be for an exposure. This allows one to actually see what is and is not in focus; but not very well, since there is less light coming through the lens and that makes it a little hard to actually see where what is in focus begins and ends.

Short answer: pressing the depth of field preview button manually closes the lens aperture to the opening it is set for, allowing one to actually see what is and is not in focus at that setting.

Oh - lenses also use to come with little booklets that had, among other things, tables that listed distances along one side, apertures along the other, and which showed in the table EXACTLY where the closest and farthest thing in focus was for each distance/aperture pairing.

{I see Manfred has already answered you as I was typing}

Thank you, John. Your explanation was very helpful.

[MajaMolly]

You may not have the time for whatever reason to take the shot, review the depth of field afterwards in the LCD and perhaps retake the shot. If that's the case, your camera may allow you to automatically bracket the aperture setting for 3 or more shots, each at an incrementally different aperture.

Thanks, Mike. That is something to think about.

[Manfred M]

I would say I shoot about 70% of my images using my camera's aperture priority mode. That means I look for a specific depth of field range, and like Mike suggest, if the subject matter permits, I will bracket one f-stop either side of where I was shooting.

To the point that John makes; the DoF markings on the old lenses, which showed the hyperfocal distances, i.e. the width of the band of distance where things are in focus for a specific f-stop. I would often focus the camera and move the focus setting forward of the subject to ensure that my foreground was in focus and my background dropped out of focus more quickly. This is unfortunately a feature we have lost with autofocus lenses (no markings) and cameras.

In going digital, we have gained a lot of new functionality, but the flip side is, we have also lost some fairly important features as well.

[MajaMolly]

I also shoot mostly in AP. My previous camera did not have bracketing capability so that is also a new feature for me. My head is spinning trying to learn all the new settings and features.

[Mike Buckley]

I actually think the depth-of-field preview button on a digital camera is only a holdover from the film cameras. Once I learned how to use the LCD effectively, I completely stopped using the preview button.

[MajaMolly]

I actually think the depth-of-field preview button on a digital camera is only a holdover from the film cameras. Once I learned how to use the LCD effectively, I completely stopped using the preview button.

What do you mean by, "using the LCD effectively"?

[Mike Buckley]

What do you mean by, "using the LCD effectively"?

When reviewing a capture, first learning how to zoom the image and inspect all of the details. Then remembering to do it. Then using a Hoodman Loupe to more easily see everything: http://www.bhphotovideo.com/c/produc...CD_Screen.html

[MajaMolly]

When reviewing a capture, first learning how to zoom the image and inspect all of the details. Then remembering to do it. Then using a Hoodman Loupe to more easily see everything: http://www.bhphotovideo.com/c/produc...CD_Screen.html

Thank you, Mike. Very helpful info.

[pnodrog]

I do not use the depth of field preview very often but when I do close up work or shots at wide apertures it is important for me to have it available. It is not a feature I would do without but it can take a bit of getting use too. Perhaps because I have done a fair bit of photography using medium format cameras that I value depth of field preview so much.

[kdoc856]

I reprogrammed my DoF preview button to be a focus lock- I use it a lot more often

[rpcrowe]

You may not have the time for whatever reason to take the shot, review the depth of field afterwards in the LCD and perhaps retake the shot. If that's the case, your camera may allow you to automatically bracket the aperture setting for 3 or more shots, each at an incrementally different aperture.

I am guessing (and it is simply a guess) that many photographers consider auto exposure bracketing as a crutch rather than a viable tool. Additionally, some varieties of cameras do not have the capability of choosing AEB and burst exposure resulting in three exposure bracketed shots after which the camera stops shooting until the next trip of the shutter button.

However, some cameras (both from Canon and from Nikon) do have even better AEB capability than my 40D and 7D. The AEB capabilty of the 7D is the same as on my ancient D60. Canon has not upgraded the capability in six or more generations of DSLR. Obviously, Canon doesn't think that this would be an important selling feature. I'd love to have a five shot AEB which would facilitate shooting HDR images.

I consider myself as a fairly adept photographer after more than fifty years of photography (much of it professional). However, I also consider AEB on my Canon 1.6x cameras as a very viable tool. I will admit that I don't use it all the time but, in certain circumstances it is a great option.

The only silly (IMO) feature of my Canon cameras is that the default setting is for the camera to cancel AEB when the camera is turned off. Canon states that this default is so that a photographer will not forget that he/she has selected AEB. However, if I am intelligent enough to select this option, I am intelligent enough the turn it off when it is no longer viable. Using the menu, I modify the default setting to retain AEB after the camera is shut down and restarted untl I opt to cancel the AEB..

I also have AEB (with the retention option) as a parameter of one of my User Selected Modes on my 40D and 7D cameras.

IMO, again, the User Selected Modes are a greatly underused capability of some Canon cameras. Canon must also think that way because they reduced the three modes on the 40D to two on the 50D and a single User Selected Mode on the 60D. I am greatful that the resumed three User Selected Mode capability for my 7D.