This is the other of today's tests: build a proper adapter for 35mm
lens and test the resolution.
The building of the adapter was quite easy because the chassis for the bellows was designed to mount also the 35mm format lens. it's a plastic board whith a hole for the M42 Tamron 28mm f2.8, the lens is screwed in a short macro tube and a M42/pentax adapter is screwed from the back of the board. so the tube is blocked and I can use the screw of the tube on the lens side to move the entire lens to tune the focus precisely.
After the build of the adapter I've done some tests outdoor, indoor and a ISO12233 test.
outdoor is just fine, nothing special: the only advantages between the camera in this configuration and a normal digital camera is only the ability to do panoramas in one step, 16bit per channel true RGB pictures, and the scanned area covers all over the lens projection circle.
This configuration can't have the amazing resolution of the large format mode, because the scanned area is so tiny, that the horizontal anamorphic resolution is too low (I'll talk about that later).
Indoor it works fine, is more sensible to light because is more concentrated compared to the large format, but always too much noise for my taste.
the ISO 12233 test was a total disaster:
As I said, the horizontal resolution is 5 times lower than the vertical so with this little scanned area the resolution is very low and cannot pass over the "7" mark of the horizontal resolution, but of course can resolve all over the "20" of the vertical.
All of the tests were done at 1200dpi, because over that number the image starts to "split" horizontally, so the vertical resolution continue to raise, but the horizontal remains there(at 2400 the separation is low enough to read the "12").
Unfortunately the only way to solve this issue is to modify the firmware of the scanner, so if you are a hacker or a skilled programmer who want to help, just contact me and I will be very grateful! ;)