Depth of Field Button

Do any of you actually use your Depth of Field Preview Button? If so, how, when, and why?

I've tried to use the darn thing every now and then, but it's so hard to see the focus in the dimmed out viewfinder that I've more or less given up on it.

I use it only occasionally, generally where the DOF is narrow. It was a lot better on film cams where the viewfinder was clearer. Mostly I ignore it.

I use mine sparingly. In most cases I generally know what kind of DOF I am going to get at the f-stop that I am using. When I really use it is things like macro, shooting near wide open. No general rule of thumb, I just use it when I feel it is appropriate to review what I am doing. I will give you that it is hard to see through the viewfinder but it gives you a good indication.

I use it for positioning my Grad ND filters. I will set the Aperture for f20., position the filter the switch to the f stop to the one I want to use for the image .

I use it practically 100% of the time.

It was on my Ft-b back in the 70's and it is what I learned on so it is just a normal part of looking through the viewfinder - like checking shutter speed and aperture. I do find it easier to use on the 5d, however. When I was using the 10d, with it's cute little demi-sensor, the viewfinder was smaller and dimmer. That made it less easy to see, so I suppose it's usefulness to you is contingent on the camera you are using.

Rad

I have noticed that when you hit the DOF preview button the flash strobes very fast. I would assume this is to get a reading for a light meter? However I find it annoying when I accidentally "bump" it and I strobe the guy beside me :-0

danedel - The flash fires rapidly when you press the DOF button because you have the Modelling flash option turned on. IF you have the 580EX you need to turn off C.Fn 10.
0 is disabled,1 is enabled.

I only use it if I'm going for a shallow DOF but it's too bright an I'm unable to use the max. apature. So if I have to use F/8.0 for example because it's too bright, I'll use it. Or I just slap on my ND filter.....

yyyyeeeesss!! Thanks!
Now I have to set that on my two units

still didn’t "de-activate" it...
I find it hard that’s its a modeling light? its a strobe, like 90 BPM...or something. but CF 10 was already sent on "0" tried "1", with no luck…I will consult the manual now 

it was CF # 6....

but thanks for the inspiration to finally fix this issue

Be careful with the 'modeling light' on the 580/430 even though it only last about 1sec it will over heat the strobe pretty quick. Check the manual out but I think it says if you use it a certain number of times over a certain period of time you need to let the flash rest like 10 min to cool off and prevent damage.

I am trying to turn it off, with CF 6 I diabled it....so it wont come on, ever