Photography/Shooting 35mm negatives (macro)
Dave, i'm converting 35mm negatives to digital by shooting macro in a dark room, inverting, post-processing raw. The end result is very good. I first tried with a small sensor compact (minimum focus distance 1-2cm) but the lens is not sharp at ~F3.5 wide. Then tried 14mm F2.5 u4/3 lens (minimum focus distance 13cm, much sharper image) and its the best i have. This cam is only 12mp, so by the time i crop and post-process the final jpeg is ~300-400kb size. I was wondering if it would make a difference in image size and detail if i upgrade my current interchangeable lens system to a different brand 20mp APSC sensor + 9-27mm F3.5-XX minimum focus distance 14cm.
I imagine the final image will be larger because of the sensor and would probably have more detail, compared to 12mp, but i don't know if one stop makes a difference in this case, or even worth upgrading. I'm not a pro.
Yes, having 20mp instead of 12mp will improve the resolution of the digital file. But I think you are looking at the f stop rating the wrong way. Your f 2.5 or f 3.5 is the widest opening available for that particular lens, and is used when you have minimal light. (A lower f stop number means that the aperture opening is wider. All other things being equal, a lower f stop rated lens is larger and more expensive. I used to have a Minolta lens with f 1.2, which was a larger diameter lens than usual, and very good for low light.) But for a finer focus over the width of the image, it would be better to stop down to a smaller f stop (a higher f number, like somewhere between f 16 and f 22, for example). The various parts of the image are different distances from the lens when the subject is close to the lens. A smaller aperture provides more depth of field, so the complete image can be in better focus. Since you will have the camera in a fixed position (such as on a tripod with remote release), you can adjust the shutter speed to be slower as may be needed for proper exposure.
Hope this helps!