Auto-Depth-Of-Field Scale?

[JamieR]

I'm currently reading "Understanding Exposure" by Bryan Peterson. He mentions a little tip about an auto-depth-of-field-scale, but it has me a little confused.

Quote:

"Some of you may own one of those new SLR (single-lens-reflex) or fixed-lens digital cameras that offer an auto-depth-of-field-scale setup; Canon is one example. With these cameras, you can autofocus your foreground, autofocus the background, and the camera will then beep only if your range of depth of field is greater than the aperture choice can offer."

Now as great as this description is, i still don't understand the purpose of it? Can someone please explain this, and a situation when it might be used?

Also does my Canon 40D have this feature? I have read through my manual but can't find mention of it.

Regards,
Jamie

 

[Josh66]

My 10s (Canon, 35mm) has this, but I never use it.

Here's what it does: You set what you want to be in focus in the foreground, then you do the same for the background. The camera selects an aperture that will make that happen.

I find it easier to just use the DOF preview.


Not sure if the 40D has it.

 

[epp_b]

Dep

 

[musicaleCA]

My 450D has A-DEP, but I haven't touched it, because it picks entirely inappropriate settings (not to mention it messes with my creative flow). I don't need f/20 to get a single subject in focus (which it'll pick if there's other stuff closer and further away from the camera but close to the subject, it seems), especially if it's a mere 5cm long. Not to mention that slows the shutter speed to absurd times like 1sec. >.< (Not to mention it doesn't let me choose my focus points...bah!)

If you don't see "A-DEP" or "DEP" somewhere on your mode dial, you don't have it. Understanding DoF by setting the aperture yourself is probably better in the long run anyway.

 

[Montana]

Yes, the 40D has A-DEP mode on the dial. I own a 40D, but I had to go look. LOL I never use it either.

 

[Garbz]

I never understood A-DEP. Depth of field is not a sharp / not sharp line. There is only 1 sharp point on the image, the focal point. The depth of field is then determined by maximal blur you will allow.

i.e. A frame which looks like it has huge depth of field on a 6x4 print may look rather different on a 12x8 when you can actually see that the background is not quite as sharp as you first thought.