06-24-2017, 11:19 PM
I do know that you do series of focus samples, so I understood why there are differences between the resolution charts and the field curvature chart. I also don't want to defend or show faith in Sigma although I admit they have my sympathy, more than Nikon does for their lenses. As I said I have doubts to decide for that lens, and part of it is of course your findings with the field curvature.
In the set of pictures I took there were a lot in narrow space, perspective distortions (not only by the lens), other things hardly impressed me - like AF failing in few pictures although I could not recognize why. Purposefully I don't say the lens failed to AF - at first, it was not at all calibrated. And I'm unclear if calibration would be easy or helpful afterwards.
But in practice I can imagine some shots blown due to field curvature and others saved because of it - would the lens be entirely useless at the borders, I'm sure you would have showed that. I also understand that doing more than unusual "border shots" to get the peak performance is annoying. But it was worth the effort, and it was also great to point that out. Otherwise people buy it, do their usual brick wall tests and complain about PZ :lol:
One of the pictures I took I was a bit puzzled to check afterwards. It was wide open @ 24 mm and from the door in the background to the white chess figures in the left corner the sharpness surprised me. Now I know, that field curvature played some part in it. That's what made me asking "is it in the wild such an issue like it doubtless is on a test chart?" Anyway, that brings the "3D-effect" to an entirely different meaning ^_^ Next time I use my 3D-glasses...
Oh, and the first guy who brought me that Nikkor to attention was a Canon photog, who praised it very much and used it with adapter. 8-10 years ago, that was. The Nikkor was for long a lens Canon shooters were lusting for, so I reckon I can refer to it. Forgive me tho post Nikon samples in a Canon forum on PZ, if you would have put more and more critical shots in your samples, I would not habe been so tempted to do so
In the set of pictures I took there were a lot in narrow space, perspective distortions (not only by the lens), other things hardly impressed me - like AF failing in few pictures although I could not recognize why. Purposefully I don't say the lens failed to AF - at first, it was not at all calibrated. And I'm unclear if calibration would be easy or helpful afterwards.
But in practice I can imagine some shots blown due to field curvature and others saved because of it - would the lens be entirely useless at the borders, I'm sure you would have showed that. I also understand that doing more than unusual "border shots" to get the peak performance is annoying. But it was worth the effort, and it was also great to point that out. Otherwise people buy it, do their usual brick wall tests and complain about PZ :lol:
One of the pictures I took I was a bit puzzled to check afterwards. It was wide open @ 24 mm and from the door in the background to the white chess figures in the left corner the sharpness surprised me. Now I know, that field curvature played some part in it. That's what made me asking "is it in the wild such an issue like it doubtless is on a test chart?" Anyway, that brings the "3D-effect" to an entirely different meaning ^_^ Next time I use my 3D-glasses...
Oh, and the first guy who brought me that Nikkor to attention was a Canon photog, who praised it very much and used it with adapter. 8-10 years ago, that was. The Nikkor was for long a lens Canon shooters were lusting for, so I reckon I can refer to it. Forgive me tho post Nikon samples in a Canon forum on PZ, if you would have put more and more critical shots in your samples, I would not habe been so tempted to do so