GMPhotography Offline Upload & Sell: On
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RCicala wrote:
I will speculate a bit - and I have no inside knowledge regarding this lens. If I did, nondisclosures would prevent me from speculating. But the actual MTFs are way worse than Sony's computer projected MTFs. That always occurs to some degree but this is way different.
1) It's possible the test doesn't accurately reflect lens performance at infinity of the 10 early copies I tested. The only way I can figure this happens is that setting focus to infinity on the camera isn't accurate on this lens (it is on all other FE lenses), but I repeated them set just past and just prior to infinity and results were worse, so I think this is unlikely.
2) It's more likely that a firmware or programming issue is causing the floating element (EM focused element) to be slightly out of position when the camera is set to infinity focus. That would certainly explain the overall results. If this is the case electronic reprogramming could fix it.
2a) It is also possible in this case that AF would give better images than the optical bench - there might be a feedback loop in the AF detection that adjusts the floating element during AF and that isn't present in 'preset focus distance'. Or might be that the lens performs much better at closer focusing distances than it does at infinity. This is very new technology.
3) There may have been a problem with manufacturing the lenses to spec. Variance was rather high with these, which kind of suggests that. A number of copies were slightly decentered or tilted, but I don't read much into that with a zoom. It's how zooms are to some degree. I wouldn't be surprised if there are some people with superb copies. But that hasn't been the overall feedback online.
We also know that there has been difficulty bringing these lenses to market. This may be just one of those things, or it may be a problem has been identified and is being fixed. If it had been because demand was just outrageous then there would be thousands of people showing off their images.
My guess is that Sony has identified an issue and is fixing it.
I've asked some of our techs to do some direct comparisons between GM 70-200 and Canon and Nikon 70-200s on adapters. I'm not all fired up about it because, honestly, until more lenses reach market I'm not sure the ones we have on-hand are going to be reflective of the ones we get in the future.
In the meantime, what it looks like is a lens that's a bit better than the previous Canon and Nikon 70-200 f/2.8 lenses being shot on a much better sensor than we had when those lenses came out. The images should certainly be good and I imagine most owners are reasonably content with it. But I suspect most of us wanted better than good from this lens. ...Show more →
Well Roger I'm renting it from you and my needs are 200mm about F4 not at infinity and in crop mode and only about 14 thousand images. Walk in the park.
I should be okay. Just tell the rental side send me a good one. Hey I'll even test a couple out if you want. Have a great Thanksgiving
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