50mm focal length


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mysum

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Apr 18, 2006
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#1
It is said that the 50mm focal length is the closest focal length to that of the human eye.

Is it still relevant in the digital age with our 1.6X, 1.5X field of view crop factor?
 

hacknet

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Mar 20, 2007
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#2
i dont know exactly how close it is, my lens book says so too. its 50mm on FF. so i guess 35 on a DSLR.

i havent tried a 35mm but the 50mm i tried this afternoon got me pretty close to what my eye sees..
 

posez

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Mar 23, 2007
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#3
not quite - 50mm on the APS sensor is a 75mm equivalent with the crop factor. Perspective changes slightly.
 

Yatlapball

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May 13, 2006
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#5
Someone should sticky the previous thread that had a long biological explaination on what our eye can and cannot see. And how 50mm actually has no real relation to our biological makeup.
 

ST1100

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Jun 18, 2003
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#6
It is said that the 50mm focal length is the closest focal length to that of the human eye.

Is it still relevant in the digital age with our 1.6X, 1.5X field of view crop factor?
The '50mm' approximation comes from the fact that 35mm film (aka 'full-frame') has a diagonal of 43mm, and a lens with that focal length would produce an image of least distortion, also popularly (ie conveniently, albeit erroneously) known as 'what the eye sees'.

The concept transfers itself to any format. For 1.6x crop, the diagonal of the sensor is ~27mm, and a 28mm lens would provide 'closest focal length of the human eye'.


HTH.


p/s to get the diagonal of any format, use pythagoras theorem on the sensor's/film's length and width.
 

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