*** 5Dc vs 60D resolution test ***

Started Mar 17, 2013 | Discussions thread
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schmegg MOD
Veteran MemberPosts: 5,768
Re: please don't twist my photos
In reply to Just another Canon shooter, Apr 1, 2013

Just another Canon shooter wrote:

MAC wrote:

crop doesn't have a penalty.  only those looking at websites that send the crop sensor backwards have the wrong impression that crop has a penalty

All those sites usually have one big chart only. The move the crop camera backwards only if they use the same but not equivalent FL. And they do not, if they use equivalent FL. Since the discussion started by the OP is for equivalent FL, then they do not move anything, and their data is relevant. It all depends on the lenses used; and even if you use the same zoom, it may perform differently at different FL. So the sensible thing would be to look at a variety of comparisons at equivalent FL's and equivalent F-stops (here, MAC is right). There is no real need (but it would be interesting anyway)  to choose ISO 250 on FF since in many situations, you can afford the lower SS. When you cannot, the 5D will take some hit since its QE is considerably lower than the 60D, and there will be more apparent noise.

BTW, all those sites measure a fixed MTF, like MTF-20, MTF-50. It is just one of the many metrics for ... call it whatever you want.

BTW, This thread is getting very colorful, since nobody bothers to cleanup the previous replies.

LOL! Yes - I was beginning to wonder just how many colours they have! Hehe!

Re the data. The MTF figures are derived - DxO don't actually measure resolution at all. They measure acutance and derive resolution from it mathematically.

Here  is the page showing the target they use. As you can see from this target, they are measuring edge sharpness. They aren't doing anything 'bogus' here, just using accepted methods.

Their graphs are called "sharpness" graphs and are, of course, designed to allow people to judge which lens will provide the sharpest image on their chosen camera (as they are lens tests after all, not resolution tests).

This whole thing has confused a few people - and it would be very good if DxO put it to bed by describing the suitability of their metrics for making comparisons. But, of course, it might not be exactly what they'd prefer to do, nor would it be easy to explain it in simple terms that everyone can understand.

It's really very simple to determine which of two sensors can resolve more detail. Peter will not meet this challenge though - he is instead interested in claiming a practical difference, rather than an actual one. And, because of this, it will be very difficult to come to any conclusions other than that the difference is not really very significant.

And, if we can even get to this point, it will be an achievement!

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