Hi, I just recently bought a Mamiya RB67 and am new to the Medium Format and I have a question.
Question: How do the lens sizes compare to 35mm format sizes. For instance I know that on my 35mm camera about how much the view angle is on a 18mm, 35mm, 100mm and what I can expect to get in the frame. What I don't know is how the view angles are on Medium Format compared to 35mm format. My RB67 came with a 90mm lens which is apparently equal to about somwhere around 40-50mm. Is there some formula to deterime how the lens compare so that when I buy another lens I know what to look for? For instance what would be the equivalant 35mm format lens to the RB67 50mm?
Hope some of this makes sense.