jan457 wrote:
Ok folks, I'm kind of new to DSLRs, but I thought it was just the opposite of what was stated above. On a Full Frame DSLR a 10-20mm lens is 10-20mm, NOT 15-30mm.
On a Nikon D3100 cropped sensor, you use the 1.5 factor because the sensor is smaller and only sees the center part of the image produced by the lens. This center part makes it seem like you are "zoomed in," so the lens on a cropped sensor has a simulated LONGER focal length.
So, the 10-20mm on the Nikon D3100 would appear to function as if it was a 15-30mm. Is this right, or did I learn this backwards/wrong??
David
Ok folks, I'm kind of new to DSLRs, but I thought ... (
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Yes and no. The field of view would be equal to that of a 15-30 mm on a full frame, but the depth of field calculations would still be based on 10-20 mm.