Last week I tried out all my lenses on the Canon 5D digital camera. It has a full 35mm sensor. Adaptors allowed me to hook up old Minolta 35mm lenses and Pentax 120mm lenses to it. I wanted to see how the coverage or field of view looked.
What I discovered was that the larger format lenses gave the same field of view as the smaller format lenses. 50mm was 50mm no matter if the lens was made for a slide film or a 6x7 film.
That said, how could I try out the huge old brass lenses made for the ULF cameras, specifically the 12 inch by 15 inch camera? Would they be more telephoto?
No. An 18 inch lens is about the same as a 4 to 500mm lens. A mm to inch web site converts 18 inches as being about 450mm. The field of view matched those statistics.
It was interesting how a picture resulted using a 5D digital camera and a 12x15 inch camera. The larger camera was set up and the back lifted. The back has the ground glass on it. The digital camera was stripped of its lens. I held the 5D inside the back of the 12x15 and moved it around to establish the shot. Exposure was made by altering shutter speed and ISO on the 5D. The lens was wide open at f:7.7
It worked. Now I can see exactly what a 35mm sensor sees on a 12x15 inch negative. The image is telephoto as if I had used a 450mm lens on a 35mm camera, although to get the entire field of view of one photo that is ULF I'd need to shoot many many 35mm images and then stitch them all together.