300D and 828 - The real issue

Started Dec 17, 2003 | Discussions thread
dpophyte Regular Member • Posts: 379
Re: 717 DOF vs. 28-135 IS lens?

dianec wrote:

Thanks for your replies. I just feel that there's a piece of the
puzzle that I'm missing.

Using the DOF calculator, I get that the 717 at 12 feet from
subject and full zoom gives acceptable sharpness from 11.7 - 12.4
feet. A 120 F2.8 zoom on the drebel gives acceptable sharpness
from 11.8 to 12.2 feet. That doesn't seem very different.

So is the drebel advantage that you can stick on a 200mm, step back
more than 12 feet from your subject, and get a shallower DOF?

Look at the wide end:

717 @ 35mm equiv f/2 10 foot subject distance, range in focus:
6.59 ft to 20.7 ft

10d w/ 24mm (35mm equiv) f/2.8 10 foot subject distance, range in focus:
7.8 ft to 13.9 ft

DOF on the 717 is 14.1 feet vs 6.1 feet on the 10d in as close to identical circumstances as you can easily (cheaply) manage. An extra 8 feet can make a big difference.

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PDM
PDM
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