DOF scales on modern lenses

I know how they work on a manual lens where you change the aperture by rotating a ring, but my Sigma 17-50 lens has one and I haven't the slightest clue how to get any useful information out of it without an aperture ring. Can somebody help explain this? I would find it very useful.

I don't understand how the method of changing aperture makes any difference to reading the DOF scales. That said, the focusing travel on modern AF lenses is so short, that DOF scales are small and not so informative.

I had some success with searching after posting this and learned what you just said, that the scales are so small they are basically useless. That's no fun, why do they even bother to put it there?

Oh well, feel free to let this thread die.

Yeah the scales on most lenses are pretty useless. Besides the DoF depends on the circle of confusion, which changes with format size (and EF lenses can be used on multiple formats, of course), and furthermore the effective DoF depends on your print size and/or amount you crop.

I'm not an old-school photographer by any means, but did people actually use them?

I still use the DOF Scale in conjuction with Hyperfocal distance shooting and when specifically trying to blur a specific part of the photo.

I only use it with my primes though.

Of course, as noted by phreeky, i had to adjust my circle of confusion for my 1.3 crop sensor ( when i had the Ti1 it was 1.6 of course).

In the end, the most useful tool is my Hyperfocal Distance calculator (downloaded to cell phone) . I then use the distance scale and DOF guide (F stop guide) to set up the shot.

If neither hyperfocal shooting or specific placement of your bokeh is necessary for your photograph(y), then I'd agree its pretty useless then

yes

phreeky wrote in post #12859981
I'm not an old-school photographer by any means, but did people actually use them?

Yes, but only on rare occasion. More often, I and others I knew used the depth of field preview button in the olden days.

phreeky wrote in post #12859981
I'm not an old-school photographer by any means, but did people actually use them?

Yep.

Jon.