On Tue, 26 Sep 2006, Chuck Norcutt wrote:
> As I promised, here are my test images from shooting the Tokina
> 28-80/2.8, Kiron 28/2 and Zuiko 28/2.8 at apertures from max to f/8 on
> the Canyon 5D. Image size: 4368 x 2904
Thanks, these are interesting - also much more useful than mine since you
have other lenses at the same magnification for comparison. I spent quite
a while examining these, have to admit that some of the results are a bit
surprising.
> Each of the test snippets is a 300x200 pixel crop. When displayed on
> your screen at 1:1 you need to keep in mind that what you're seeing
> would be like taking a snippet from a 30x45" print or even larger
> depending on your screen's pixel pitch.
It's OK to compare these to my crops I think - I calculated that your
crops are 6.89% of the frame height while mine (150x150) were 7.5% - the
final print size would be quite close.
> Conclusion: There are certainly some differences bewtween these lenses
> and the Kiron is notably softer at the edge until f/8. There also may
> be a bit of vignetting with the Kiron at f/2 but it's hard to say.
> Beyond that I don't think the differences amount to a hill of beans
> unless you're really into 30x40 prints examined at reading distance.
My observations: first thing I noticed is that the Kiron seems to beat the
Tokina in sharpness in the center - but that difference, as you note, is
pretty insignificant after you've compared the edges also.
I can clearly see the characteristic halo around highlights in the center
f/2 shot, so it's not something unique to my lens. It totally disappears
at f/2.8 (is there a scientific name for this? aberration?)
But yours still seem sharper. Either that, or I've gone cross-eyed from
staring at the pixels for too long already.
I'm guessing the full frame picture showing the crop areas is the Kiron @
f2 shot. Correct?
priit.
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