# calculating focal length on crop cameras

Started Aug 29, 2011 | Discussions thread
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calculating focal length on crop cameras

It's my understanding that crop cameras have a multiplication factor of about 1.6 when determining the actual focal length of a lens. (Please correct me if I'm wrong.)

I was hoping someone could shed light as I have a question about the zoom range of a lens when used on a crop camera vs a full frame camera. So as an example, it's my understanding that 50mm is considered to be the closest to how the human eye sees the world. If I have a full frame camera, using a 50mm would equal 50mm because there is not multiplication factor. Now if I put that same 50mm lens on a crop camera such as a 7d, it's my understanding the that actual focal length would be 50mm x 1.6 which would actually equal 88mm. Is my thought process correct or am I completely off? My thought is if I were to try to get a lens to come as close to 50mm using a crop camera, I'd have to get a 35mm lens because that would be 35mm x 1.6 = 56mm.

Can someone tell me if my thinking is way off or not?

halfmonkey's gear list:halfmonkey's gear list
Canon PowerShot SD550 Sony RX100 V Sony Alpha 7R II Sony FE 55mm F1.8 Sony FE 35mm F1.4
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