Parallels Between The Human Eye and The Camera

• f2.1
• 1/50th shutter/refresh rate
• 5 megapixels
• 6.5 stops of dynamic range.
• ISO of 800
• 20mm focal length (on 35)

More Information

The refresh rate of the eye/brain combination is 1/50th. In some circumstances the average person can register up to 1/120th of a second. Fighter pilots and professional goalies have sensitivity beyond that which leads one to believe this is a skill and improved upon.

The eye has a static dynamic range of 6.5 f-stops and 20 stops with iris adjustments.

f-number varies from about f/8.3 in bright situations and f/2.1 in the dark. When two eyes are factored in no proper equivalent can be found. Choosing an f-stop is probably the cinematographer’s most critical choice.

Resolution estimated around 5MP with noticeably higher resolution in the middle. The human eye gathers resolution as the eye moves over an image and when two eyes are factored resolutions are combined. Given time and eye movement the eye can register 576 megapixels of information.

ISO is probably the most difficult calculation as the eye’s persistence of vision and increasing rhodopsin in the dark can expose a starry night. In most situations the eye is roughly equivalent to 800ISO.

Focal length:
Object focal length of the eye = 16.7 mm
Image focal length of the eye = 22.3 mm
Distortion-free lens=50mm

Originally published at voshart.blogspot.ca on January 24, 2009.