I am working on a custom setup where I am using a DSLR lens (Canon 50mm f/1.8) to project an image onto an image sensor (image plane). For my application, I require a very large distance between the last lens and my image plane. The issue I am running into is that a typical DSLR lens has a short (~42mm) flange focal distance (back focal length).
Here is the schematic of my setup:
Is there any way I can increase the flange focal distance of the DSLR lens? I prefer to have 100mm or greater flange focal distance.
I read about retrofocus and I think the solution is is to add a "negative" lens group in front of my DSLR lens. Is there a standard off-the-shelf set of negative lenses I can put in front of the 50mm DLSR lens to increase the back focal length? If so, how do I go about choosing the correct approach?