Switching lenses to digital camera

[Richie]

I was told that if I switch my nikkor 50mm lens to a Nikon digital SLR camera, the lens would become a 100mm lens. Is this true ? do I loose f stops? what would happen?

Richie

[Photo-John]

I was told that if I switch my nikkor 50mm lens to a Nikon digital SLR camera, the lens would become a 100mm lens. Is this true ? do I loose f stops? what would happen?

The sensor in the Nikon digital SLRs is smaller than a 35mm film frame. That means that the image that a 35mm camera would capture is actually cropped. It's not quite the same as your lens actually changing focal length. The depth-of-field stays the same, the magnification stays the same, and any distortion is the same. Just imagine making a print from a 35mm image and cropping it. That's exactly waht happens.

It's not a 2x difference, like you thought. Your 50mm lens would become an effective 75mm lens, with a 1.5x crop factor. For some applications this is good, and for some it's bad. I love being able to use my 50mm f/1.4 lens for a portrait lens with my EOS 10D. But I also like using super wide lenses and when you crop, you lose some of that ability.

The best thing about the digital crop is that it hides the flaws in a lot of lenses. Most lenses exhibit the most problems on the outside of the glass. Having some digital cropping eliminates a lot these problems.

I think that about covers it. Let us know if you have more questions.