>There must be some incredible sample variation ...
It seems to be all to common for most of the manufacturers.
While it's hard to test for all the potential problems, I think a de-centered element are the most common problem I've found, and I always test for it by taking shots at infinity where I have a sharp "horizon" line (nearby mountain tops for me). The un-sharpness on the edges, both when shot horizontally and vertically, should be equal. A de-centered element will often cause one side to be less sharp by a fair margin.
Shooting sharp objects at a distance in to check against other lenses and to check out the relative sharpness at various apertures is also easy.
I've sent back a fair amount of equipment, but the last 2 Canon L lenses have been good samples.
>That being said, my own copy performs as described by DPReview's test--it's really incredible
Mine also seems fine.
As the article and you noted, the IS is not as effective up close as at a distance. For close up, I think 1/250 is still a really good idea. And, as you mentioned, the fore-aft movement is not compensated for by the IS. So, I have out of focus shots fairly often.
> (and as a shooter who is recently coming back to small format from Schneider glass on Rollei and
> Zeiss on Hasselblad, that is saying something).
I'm coming from Rollei SL66 & TLR 2.8 Planar (Zeiss), Bronica RF 645 with Tech Pan, for 16x20 & 22x28 B&W.
>... I find the 50/1.2 (considering what you pay) is a mediocre performer, that actually never
>really gets crazy sharp even at f5.6 or f8...
I had the same experience with the 85 1.2 for the old FD -- love the 85 1.8.
I hope we get IS for other good prime lenses. I think even wide angles would benefit.
IS really is a serious technical advance. It makes me wonder whether Zeiss/Cosina could use the Sony 25 mp chip and chip-based IS for the M mount and all those optics. Combined with the viewfinder based live view we have a lot to look forward to in terms of performance.
> The 100L lens is one of the good ones!
So far I'd have to agree.
(I have a sample shot on my home page.)