TheWengler
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 p.2 #3 · to crop or not to crop? | |
mjeffbr wrote:I do not know why the same lenses get much better reviews for crop sensor cameras (they post two reviews of each lens), but as he posts all the test results one should assume they have some credibility, even though I think for a moment that the same results could be taken as “better” simply because you have a crop, so for a crop shooter it’s ok, you should be thankful, but for a full frame you deserve more…
I was pretty convinced that FF was the way to go, but now I kinda have that doubt, an example: the 70-200 2.8 II is near perfect for FF, and flawless for Crops, the same goes to many other lenses, some are ok for FF, but very good for 1.6x cameras, like the almighty 85 1.2, which, according to them, is not so good for FF
The weak point for most lenses will be around the edges. So when you take a lens designed for FF and put it on a cropped body, you're eliminating the softest areas. This is why they score better on the tests when tested on cropped cameras. The 85/1.2 gives mediocre border results in his tests so he gives the lens a score of 3/5. Everyone knows that border resolution isn't a key element for this lens hence the 4.5/5 for field quality score.
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In an image, universal sharpness (whatever that is) would be horrible. Mr. Gardner - as he always does - has provided a superb technical explanation of why this is so. For Photozone or anyone to suggest that Canon's best primes aren't all that good because they are better on a crop camera than a full frame one is just stupidity. Every lens (at least those affordable to mere mortals) has some degree of distortion or softness in one or more of its aspects. Again as Mr. Gardner has noted this is because we are attempting to capture a 3 (really more) dimensional world on a 2-D plane. Fundamental geometry says something has to give.