IQ of 7d w 15-85mm Vs 6d w 24-105mm?

Started Mar 8, 2013 | Questions thread
qianp2k
Senior MemberPosts: 9,971Gear list
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Re: presentation.
In reply to usedtobedontrustme, Mar 11, 2013

usedtobedontrustme wrote:

Mako2011 wrote:

qianp2k wrote:

usedtobedontrustme wrote:

qianp2k wrote:

24-105L on 6D will have much better IQ - sharper, resolve more details, better color tonality, better DR, better SNR (which means less noises/grains in entire ISO range) and of course much better high ISO.

DXOMark 24-105 on 5D2 vs 15-85 on 7D

DXOMark 6D vs 7D sensor test

DXO says the 6d & lens combo has 50% better sharpness. That is huge and I hope that is accurate. 20% better sharpness would be worth it to me.

The reason FF set is sharper is because it has 1.6x less pixel magnfication.

That would indicated a misunderstanding of the things that affect sharpness. Perhaps related to the cloak surrounding M-pix. First, it is important to compare systems at the same DOF when discussing sharpness. You may have not considered that. To compare sharpness you need to start from Equivalent photos. DXO is not doing that. While the overall sharpness is often the same or better with FF, the issue of evenness of frame needs to be considered, and taken on a lens-by-lens basis as well as comparing like photos. Your examples do not do that and DXO makes many of the same mistakes in presentation. Their strike zone is very large...nice for tee ball but not as useful for a fast pitch game game.

Are you saying that DXO doesn't measure sharpness across the whole frame?

http://www.dxomark.com/index.php/Lenses/Compare-Camera-Lenses/Compare-lenses/(lens1)/164/(brand)/Canon/(camera1)/483/(lens2)/239/(brand2)/Canon/(camera2)/0

they do although didn't give explicit MTF data but you can judge by colors in Measurements | Sharpness | FieldMap.  You can select focus range and F stop to get an idea.

Does DXO assume that if a lens is wide open, small DOF is necessarily desired?

Shooting at equivalence DOF is complete nonissue such as



40/2.8 STM pancake wide-open at F2.8 in this deeper Cathedral

Actually FF has better DOF control and can increase F number dramatically w/o suffering noticeable diffraction. Try ISO 100 based 7D you will know the difference. The key here is to stop down waterfall.





5D at ISO 50, F22 with 17-40L w/o a ND filter





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