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Topics - Pancho

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EOS Bodies / 7D Mark II ISO ramp-up on final version
« on: October 27, 2014, 06:38:35 AM »
Focus Numerique, a french gear reviewer, has put his hand on a final version of the 7D Mark II. They have made an ISO ramp-up and the raw files are available. The other test images (available on the other pages) were done with a prototype version.
Here is the link (sorry, it's in french...)
http://www.focus-numerique.com/test-2007/reflex-canon-eos-7D-mark-ii-bruit-electronique-12.html
And don't look at the typo on the sensor's size and definition of the Alpha 77 II...

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Technical Support / Autofocus working conditions
« on: December 06, 2012, 11:01:08 AM »
I have a candid question about autofocus functionality.

Majority of Autofocus are working with a lense at f:5.6.
Some (very) high cost DSLR can work with lenses at f:8.

What is the limiting factor?

Is it the AF system illumination? I'm not sure, because if the AF system can work with a f:5.6 lense at 0EV, it would be able to work with a f:8 lense with 1EV illumination...

Is it a question of Deth Of Field? At f:8 we have more DoF than at f:5.6 and then less precise error measurement inside the AF system.
But if the AF system is able to work with a 18mm f:5.6 at 15m distance, why wouldn't it be able to work with a 400m f:8 at 3m distance?

Thanks for your help.

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