rscheffler wrote: zhangyue wrote:
This 28cron is noticeably sharper than old version on M10. It is very good to corner at f2 on M10P already. I think I can use it at that aperture on M if DOF allows which is not the case with old cron. On S1, at f2, the corner is mushy, but at f2.8 is clearly improve a lot that I don't see this much of improvement with one stop based on my experience with adapting M glasses, usually the effect is way more gradual on non-Native body and some never be able to catch up. and as mentioned, at f4, it is good enough but after f5.6, I am happy to use it for critical landscape shots.
The lens is very tricky that I found it has quite significant focus shift.(and exhibit more so on S1 than M10P which add more confusion) I don't remember see this documented anywhere and I don't remember old cron has this much focus shift at all. If I didn't find this during testing, my results will be very miserable, and then people will all have different information about this 28cron now.
Given there is so many variables involved, adapter, body, methodology and inspection(be able to analysis results), that is why nowdays, I almost only trust myself on lens testing than any internet experience and good testers are all go to sony and forget about M glasses. Because ultimately, it is the system I assembled for my own use. I consider this is a must step to use any lens or system wisely.
Sorry to continue off topic, but that's a very interesting set of observations about the new 28 Cron. Not sure if you recall, but I bought two copies back a few years ago (2016?) and wasn't happy with either (ended up with the Lux instead). The first was a dud with very poor RF calibration that was way off. The second was properly calibrated, but I found that as I stopped it down it developed massive field curvature. I posted about this on LUF and got samples from a couple other photographers... Some stated they had no such field curvature problems, but those didn't provide image samples for comparison. Of the image samples I received, I could see the field curvature in some.
Are you finding that at f/4 and further stopped down that the lens remains as sharp into the edges/corners as it is in the center? This is where my copies disappointed me. In comparison, side by side, the CV35/1.7 whipped the new Cron. The issue of focus shift sounds familiar but I would have to go back to my test images to see if in fact I also noticed any shift.
This is not the first time I've heard of VERY mixed results with M lenses to the point where it defies what you would think possible for a lens with the same optical design. I've encountered a few oddities myself but it's too OT. Though I don't mind if you guys take this forum off topic I'm not fussed.
Nov 02, 2019 at 11:23 AM
Previous versions of adamdewilde's message #15033079 « Sigma FP - In hand first impressions. »
and good testers are all go to sony and forget about M glasses. Because ultimately, it is the system I assembled for my own use. I consider this is a must step to use any lens or system wisely.