APS-C lenses

Aharami

Lifer
Aug 31, 2001
21,205
165
106
does the focal length multiplier come into play for APS-C lenses also? Since the lens is designed specifically for crop sensors, do they design it with correct focal length markings? I'm wondering if 17mm on my Tamron 17-50 is really 17mm or is it 27.2mm
 

Madwand1

Diamond Member
Jan 23, 2006
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0
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Originally posted by: Aharami
does the focal length multiplier come into play for APS-C lenses also? Since the lens is designed specifically for crop sensors, do they design it with correct focal length markings? I'm wondering if 17mm on my Tamron 17-50 is really 17mm or is it 27.2mm

Technically, the focal length does not actually change when you put a lens on a crop format camera, so the actual focal length is 17mm (or so) when the marking says 17mm.

However, from the perspective of full-frame equivalent field of view, 17mm on a 1.6x crop camera would give a similar field of view to a 27.2mm lens on a full-frame camera, as usual.