Thank you for sharing this post, great information.
I have used, the Componon-S, and Nikkor EL, both 50mm f2.8 lenses. I found the Schneider performed slightly better away from the center than the Nikkor EL, with f4. In both cases, the lenses were reversed mounted with a 23.2 x 15.4 mm CMOS sensor (Nikon DSLR D3200). Both lenses definitely resolved enough to see the grain, and even minimum scratches/dust.
In general, for this use case, enlarger lenses are designed to best focus at a flat surface (paper) and from a flat subject (the film). And have the added value of being relatively inexpensive for the use case.
A few items I found extremely critical for best quality away from the center, with both lenses:
- Select the best aperture for sharpness and resolution. This was specially critical with the larger sensor, one stop less was not as noticeable with the smaller sensor. The coinimaging site provides a great reference, and it also shows the significant loss of resolution on the corners.
- The depth of focus is very small, and any misalignment between the target, the lens, and the lens and the sensor is highly noticeable.
- Check the IR filter of the HQ camera for spots… there are some postings on the subject at the camera forum. I no longer have a filter in the sensor, so cannot provide a reference.
With both the Componon and Nikkor grain was nicely preserved, here is an example of the Nikkor EL on an earlier post., the Schneider is slightly better on the corners. The film was shot with the emulsion-side to the lens, using the 1/2 stop between f4 and f5.6, and D3200 DSLR.
The illuminant configuration is also a very significant part of how the grain looks, and it took multiple iterations to get to something decent (an oversized ping pong ball).