rscheffler Offline Upload & Sell: Off
|
My guess is there's some additional field curvature induced by the sensor toppings at play here. I still haven't snapped up this lens, but from what I shot with it at PPE and seen from others, it should have a pretty flat plane on Leica M. I would expect it to be better on a modded Sony.
That said, this kind of look, where there is some field curvature towards infinity at the edges and objects in the background become more defined, is fairly common with RF lenses. Most I have tried, that exhibit some field curvature, tend to do it in the direction towards infinity, which always results in better/smoother blur in the centre of the image, and more defined and less appealing blur at the edges.
With a thick sensor topping this would seem to be exaggerated and appears to have been predicted by Nasse in one of his Zeiss papers:
"If the (sensor topping) filter is significantly thicker, the contrast transfer for the image edge becomes worse for tangential structures. In the graph of the curves, this looks like the old retrofocus lenses but is caused by astigmatism rather than lateral chromatic aberration. The focus is shifted to greater distances for tangential structures by the additional path through the glass."
|