field of view cropping

[bobrobert x]

An article of Michael's stated that in focal length terms that 50mm was the equivalent to normal human vision and in digital equivalent it was about 31mm on a canon camera lens Is he correct? Field of view cropping on a digital camera is smaller by about 2/3 thirds so I would have thought that the it would have been about 80mm Am I missing something in my thinking process? TIA

[dlashier]

Bob, you're just applying the ratio backwards. 2:3 = 1:1.5 and 1.5x31mm = 46.5mm. (and actually consumer canons are 1.6 so 31mm x 1.6 = ~50mm).

- DL

[Eric Myrvaagnes]

An article of Michael's stated that in focal length terms that 50mm was the equivalent to normal human vision and in digital equivalent it was about 31mm on a canon camera lens Is he correct? Field of view cropping on a digital camera is smaller by about 2/3 thirds so I would have thought that the it would have been about 80mm Am I missing something in my thinking process? TIA
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Most Canon cameras have a sensor that is smaller than a full-frame 35mm film (24x36mm). The "crop factor" is 1.6 (except on the 1-series and 5D), which means that to get the same field of view on one of these cropping Canons as on a traditional 35mm film camera with a "normal" 50mm lens, you need to use a lens which is wider than 50mm so that when cropped to the sensor size, you get the same field of view as the 50mm lens on the standard film camera. A 31mm lens gives you the right focal length for the cropping Canons, because 31 times 1.6 is just about 50.

I hope this helps.