04-08-2015, 03:58 AM
Technically it is nonsense to produce an MTF chart when ignoring the field curvature. However, it would still be a qualitative presentation method which shows when/how the field curvature is eventually masked by the depth-of-field. The question is how much value there is in this (as opposed to providing just a textual guidance).
In case of the mentioned Samsung lens, you can at least notice that the depth-of-field is insufficient at mainstream aperture settings. Now, as you mentioned we could only do that for the object magnification ratio that we are using.
A plot is possible but would require an extra workflow - thus rather than keeping the magnification constant, we would need to move backward/forward and measured the different distances. I am not so sure whether I'd like to follow that path in terms of required efforts. Measuring flare has a higher priority (well, the new portal comes first once Markus manages to free some time again for PZ).
In case of the mentioned Samsung lens, you can at least notice that the depth-of-field is insufficient at mainstream aperture settings. Now, as you mentioned we could only do that for the object magnification ratio that we are using.
A plot is possible but would require an extra workflow - thus rather than keeping the magnification constant, we would need to move backward/forward and measured the different distances. I am not so sure whether I'd like to follow that path in terms of required efforts. Measuring flare has a higher priority (well, the new portal comes first once Markus manages to free some time again for PZ).