When preparing for my guest stint on This Week in Photography (I know, I managed to disguise well the fact that I’d prepared), I made myself a little cheat sheet for some popular sensor sizes. It occurred to me that y’all might find it useful.
The RED Mysterium sensor is very close to the size of motion picture film (Super 35), which is as wide as the full-frame 35mm SLR frame is tall. The “small” DSLR chips are very close to this size, meaning that an inexpensive DSLR can have very similar depth of field characteristics to the movies.
Here’s an image that shows how a lens of a given focal length projects onto the various sensor sizes. It’s easy to see the “crop factor” at work here, and how a 50mm that is “normal” for a 5D would be a super telephoto if you could somehow slap it onto an LX2. It takes a 35mm lens to project an image onto a DX chip that matches the Angle Of View of a 50mm on the 5D or D700. You can visualize this by imagining what happens when you move a projector closer to the screen: the image gets smaller. If you wanted the above image to fit within the DX sensor, you’d have to move the lens, which is very much like a projector, 15mm closer, making it a 35mm lens.