Depth of Field Button Question

Can someone explain to me what the depth of field button does and how or why I would need to use it? Thank you.

RonA18 wrote in post #11424709
Can someone explain to me what the depth of field button does and how or why I would need to use it? Thank you.

I could explain but I am too lazy!

Quick Google search:

http://www.slrphotogra​phyguide.com …ield-preview-button.shtml

http://www.digital-photography-school.com/depth-of-field-preview

And one more from our own forum here: https://photography-on-the.net/forum/showthre​ad.php?t=275855

It stops the lens down to the taking aperture so you can see an approximation of the DOF through the viewfinder.

When you focus your camera, or AF is focusing for you, the lens is always open to its maximum aperture, so you don't see the final depth of field from your photo through the viewfinder.

Pressing and holding the preview button stops the lens' aperture down to what you have set for the image and lets you see that DoF in the viewfinder. It's tricky to use past f/8 because the image in the viewfinder gets too dark.

So, for example, if you're using a lens with a max aperture of f/4, but your shot is set to use an aperture of f/11, the aperture is at f/4 all the way until you press the shutter button; at which point it closes down to f/11 just long enough to take the shot.

I've found it fairly useful for Macro shooting, but not much else.

It just stops the lens down to whatever your setting is. Normally the lens is wide open and only stops down when you take the photo.

This always confused me... All it does it darken the edges of my viewfinder when I used it, and honestly made little to no sense for me.

Oh well, its AF Servo - One Shot button now

Invertalon wrote in post #11424783
This always confused me... All it does it darken the edges of my viewfinder when I used it, and honestly made little to no sense for me.

Oh well, its AF Servo - One Shot button now

You aren't looking the darkened image carefully enough. It does more than just darken.

msowsun wrote in post #11424801
You aren't looking the darkened image carefully enough. It does more than just darken.

It gives you a preview of the depth of field .

It made great sense back in the days of film, when viewfinders seemed - subjectively - much brighter. Even on my 5D which does have a bright VF image for a DSLR, I find the DoF button of limited use
above 5.6.

I've tried it and it didn't work. In fact, the last time I pressed the button I got a scrolling advertisement at the bottom for Extenze.

I don't use the DOF button much, but the DOH button gets hit accidently once in a while

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DOF preview is most useful when using a long telephoto lens since the DOF is so shallow, BUT when using a long telephoto, I almost always shoot wide open so that I can use a fast shutter speed and low ISO which means that DOF preview and the normal wide open view are the same.

DOF preview is the least useful with a wide angle lens where almost everything is in focus even at the widest aperture.

I tend to agree with the comment that macro is the best use for DOF preview.

Thanks all for the great info and for the comedy as well. I just picked up the 100mm Macro and will see how this feature helps.

Others mentioned that your preview is at your lens' max aperture and thus DOF. Pressing the preview button instantly stops the lens down to the preset aperture. If that aperture is 1 stop smaller you'll see very little difference in darkness or DOF. If its f-16 or smaller you'll see a MUCH darker viewfinder and a distinct difference in DOF....once your eyes get acclimated to the difference in light. A trick is (in manual aperture) click the preview button and then spin the aperture control to increment from widest to desire smaller aperture, coincidentally incrementally acclimatizing your eyes to the diminishing brightness. Once you get conditioned/trained to assess DOF in dimmer light, this can be a very handy feature. I just would like a camera with a more readily/intuitively accessible DOF preview button as I'm always fumbling around the front trying to find mine.

Great tip. I'll have to check it out.