DOF button on cameral body

I can't figure out how this option works.

When I press the button the viewfinder screen darkens slightly but I don't see much of a change otherwise.

Hi Michael,

Pressing the DOF button closes the aperture of the lens down to whatever it is set at. This lets less light into the viewfinder, resulting in the darker view you are seeing. It also allows you to get an idea of the depth of field at the particular aperture you have set. DOF being the distance in front of and behind the object you have focussed on. The larger the f number, the greater the DOF, and the lower the amount of light entering the viewfinder and ultimately the sensor.

mikecox wrote in post #17047030
I can't figure out how this option works.

When I press the button the viewfinder screen darkens slightly but I don't see much of a change otherwise.

If it only darkened slightly, you probably weren't stopping down very far? That would mean that the effect isn't very obvious. If you set the camera to f/11 (or smaller if you are using a slow lens) then look at some detail that is soft in the viewfinder but not extremely close or far away, you should see it sharpen up as you stop the lens down with the DOF button.

It does take a little time to get the feel of using it, I used it for many years shooting film so it seems quite natural to me. Once you have played with it for a while you should start to get a feel for using it.

I no longer have a camera with Live View, so I'm curious how the DOF button behaves if you're in Live View, and specifically if you are zoomed in so that you could see the details that would be soft wide open but would sharpen up with the DOF button pressed?

Using a viewfinder can be tricky unless you can clearly see the objects that are noticeably soft in the "normal" view!

I'm asking, but I haven't been a DOF button user myself!

If you're focused at infinity, you may not see any differences in DoF, particularly with slow (aperture-wise) lenses and/or short focal lengths (wide angle views). With faster glass/at close focusing distances/longer focal lengths, it'll be more readily apparent.

tonylong wrote in post #17047100
I no longer have a camera with Live View, so I'm curious how the DOF button behaves if you're in Live View, and specifically if you are zoomed in so that you could see the details that would be soft wide open but would sharpen up with the DOF button pressed?

Using a viewfinder can be tricky unless you can clearly see the objects that are noticeably soft in the "normal" view!

I'm asking, but I haven't been a DOF button user myself!

Live View is where the DOF preview really shines IMHO. If you have Exposure Simulation enabled then the LCD doesn't darken like the viewfinder does and you can really see the change in DOF.

tonylong wrote in post #17047100
... so I'm curious how the DOF button behaves if you're in Live View, and specifically if you are zoomed in so that you could see the details that would be soft wide open but would sharpen up with the DOF button pressed?

Live view really shows how aperture changes affect DOF. Zooming in is even more telling.

I must say, I've never thought of using DOF Preview in LV. I very rarely use it anyway. I kinda forget that it's there!!

LeeRatters wrote in post #17047722
I must say, I've never thought of using DOF Preview in LV. I very rarely use it anyway. I kinda forget that it's there!!

For tilt and/or macro/near macro, it's a very useful.

I would use it more, except it is in such a inconvenient location on both my 7D, and 6D. It needs to be closer to the shutter button, and more exposed or raised above the body contour. I find the DOF preview to be a valuable part of the camera.

Tried it a few times on my 60D but IMHO it's the most useless and and inconveniently placed feature on the camera.

I use it all the time, it's easy to hit with my pinky on a 1D,.

Yep I use dof preview in live view all the time for my landscape stuff, really helps!

We haven't heard back yet from Michael (the OP) --

I'm curious as to whether you want to experiment with this stuff? Using the button viewing through the viewfinder, then trying it out with Live View?

WhyFi wrote in post #17047867
For tilt and/or macro/near macro, it's a very useful.

This
I'd go even further and say it's essential (LV, exp sim, 10x DoF preview) if you want to get the most out of the tilt functions in a TS lens. For landscapes without a TS lens, you can check near and far focus points in the image that will be acquired (not the ones in some DoF table) and only stop down as much as is absolutely needed - can help minimize diffraction losses if deep DoF is needed.