View single post by jk
 Posted: Wed Apr 18th, 2012 03:40
jk



Joined: Mon Apr 2nd, 2012
Location: Carthew, Cornwall, United Kingdom
Posts: 6880
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Doug wrote:
Before you decide to jump either way have a read of the article at the following link

Lens Variation:LINK

Roger Cicala
Lensrentals.com Wrote:

... I don't say conclusion, because this little post isn't intended to conclude anything. It simply serves as an illustration showing visually what we all (or at least most of us) already know:
Put different copies of the same lens on a single camera and each will vary a bit in resolution.
Put different copies of the same camera on a single lens and each will vary a bit in resolution.
Truly bad lenses aren't a little softer, they are way softer.
Autofocus isn't as accurate as live view focus, at least when the camera has not been autofocus microadjusted to the lens.
All of this needs to be put in perspective, however. If you go back to the first two charts, you'll notice the bad copies are far different than the shotgun pattern shown by all the good copies. And when we looked at those two bad copies, we had to look fairly carefully (looking at 50% jpgs on the monitor) to see they were bad.
The variation among “good copies” could probably be detected by some pixel peeping. For example if you examined the images shot by the best and worst Canon 100 f2.8 IS L lenses you could probably see a bit of difference if you looked at the images side-by-side (the images I took on my test camera). But if I handed you the two lenses and you put them on your camera, they'd behave slightly differently and the results would be different.
So for those of you who spend your time worried about getting “the sharpest possible lens”, unfortunately sharpness is rather a fuzzy concept.
Roger Cicala
Lensrentals.com
October, 2011


I think this is excellent comment.

We need to remember that while lenses are manufactured in a factory process the products are not identical but similar.



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