Yes, In my case there are advantages to not moving the cameras. My cameras are relatively heavy compared to the point-n-shoot compacts used by most in these forums. I have a pair of Canon DSLRs that I put on tripods on either side of the scanner. Doing this allows me to reposition the cameras depending on the page size (my scanner supports up to 12" x 14" pages) to utilize more of the available camera sensor resolution. I also don't like the idea of my cameras moving while I scan books. I will typically use longer shutter times to shoot with a reduced ISO in an attempt to reduce graininess in the images so the less chance of some settling after turning a page and lowering the platen the better. I also don't have to worry about cables attached to the camera (USB/power) flexing each time I move the platen.davidlandin wrote:Do you see any advantage in having the cameras mounted as part of a separate structure?
There shouldn't be a focus problem between the front and the back of the book (I haven't seen one, anyway and the math can prove it). I don't scan particularly thick books, so I made a mock up this afternoon using a cardboard box underneath a large gardening book that would emulate a 4.25" thick book and used an 8.5x11" page with text from my laser printer as the page content for scanning.
Below are subrects of the images of what would be the first page of the book vs. the last page of the book. This is the untouched jpeg image coming straight from the camera and I don't see any difference in focus between the two. Measuring from the page surface to the image plane of the camera was the same distance (27.75") in both cases. The only thing that moved between the shots is the cradle moving horizontally so that the platen would come down into the book's gutter properly from first page to last page (as most all scanners do).