I am not a large format photographer yet but is seriously looking into it. I have a debate with a friend and I hope someone here who has real life experince with large format can give me a definitve answer.
My friend is of the opinion that for a lens to throw an image circle large enough to be used on a large format camera, it needs to be farther way from the film plane than on a smaller format camera like a 35mm camera. For example, he claims that if you use a 100mm lens on a 35mm camera, the theoretical centre of the lens would be 100mm from the film plane. But he maintianed that if you use a 100mm lens on a large format camera, the lens needed to be further away from the film plane to throw a much bigger image circle than on the 35mm camera i.e. the lens needed to be significantly more than 100mm away from the film plane.
I told him that he was wrong and the focal length of a lens and hence the lens to film distance is constant and doesn't change simply because you have changed format. I maintained that lenses designed for large format cameras have inherently a much larger image circle compared to 35mm. This factor is independent of lens to film distance. So a 100mm lens on a large format camera focusing at an object at infintiy would be 100mm away from the film plane, just as it would be on a 35mm camera.
I would appreciate it very much if someone give me me a conclusive answer. Thanks!