"Normal" focal length?

Question

The true "normal" is determined by matching the focal length to the diagonal of the negative. This would mean a "normal" lens for 35 mm would be 43 mm. I never understood why 50-55 mm lenses became the standard prime lens on these cameras. Do the math and you will see that a 6x6 cm camera would use an 85 mm lens as the prime lens and, in fact, that is what they ALL used. If a 35 mm negative was as tall as it is long, 50 mm would work out perfectly. Does anyone know how 50 mm was chosen as the "normal" for 35 mm instead of 43 mm?

(A 35 mm negative is 36 mm x 24 mm.)

You're right about the view of a 50 mm lens being approximately "normal" when compared to the naked eye, but there is a reason why it works out that way.

I'll have to go look at my camera now, but I think 50 mm is slightly on the "long" side for 35 mm.

Answer 1

I believe the focal length comes into it to (distance from the rear optic to the film (or sensor), But I think the 50mm was adopted because the 35mm tended to get something of a fish eye look?

Answer 2

Normal Focal Length

Answer 3

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RE:
"Normal" focal length?
The true "normal" is determined by matching the focal length to the diagonal of the negative. This would mean a "normal" lens for 35 mm would be 43 mm. I never understood why 50-55 mm lenses became the standard prime lens on these cameras. Do the math and you will see that a...

Answer 4

17 mm is not suitable for either portraits or bird photography. For portraits, you want a lens that is slightly longer than the normal focal length. For birds, you want something that is considerably longer than normal. If you have a conventional 35mm film camera for a full-size (professional) DSLR, normal focal length is about 50mm. The sensors on most amateur DSLRs is smaller than the traditional 35mm film frame, so 'normal' is different - for example, in the case of Nikon DSLRs, normal is about 35mm. Since you didn't specify which camera you have, I can't give you any more explicit advice.

Answer 5

I could be completely off base, but I was under the impression that 50mm is about what the naked eye sees for a focal lenght, therefore it became the standard. Any thoughts on that one??

Answer 6

actually the 35 mm was once the "normal" lens for 35 mm film but the 35 mm lens tends to add a bit of distortion to the image and the 50 mm lenses are easier to build than an odd ball 43 mm lens.