16 Unique Features That Your Camera Probably Doesn't Have

Started 4 months ago | Discussions thread
bobn2 Forum Pro • Posts: 69,811
Re: Telecentric .... or not.

Muster Mark wrote:

I think before judging it to be 99.99% baloney one should compare to lenses on other systems (I am not saying you personally should have, sounds like a lot of work), but I don't think we have the information to judge yet. Their stated goal was to have more perpendicular light across the frame. Obviously a telocentric design means a mathematically 90 degree angle of incidence. It doesn't need to be mathematically perfect to get the optical benefits though.

You showed it can't actually be perfectly telocentric on a lot of the lenses, or perfectly 90 degrees. Ok. Sure, that doesn't means the angle of incidence is not a lot closer to 90 degrees than traditional dslr lenses which was the point. Anyway, I am sure if you looked at a 2x crop of the central part of a FF sensor, it would look pretty telocentric too, so ultimately I am not sure what to think I guess.

nO Four Thirds lens was ever remotely telecentric, by the normal definition of the term. The Olympus marketing people redefined it to mean what they wanted, which was that the exit pupil was a bit further from the focal plane than usual. Plus, you have to remember that all of that early Olympus marketing guff was comparing with 35mm film, not other digital systems. Every other manufacturer when they made 'designed for digital' lenses also moved the exit pupil away from the focal plane, and there is nothing particularly special with Four Thirds lenses in this respect. With the recent trend to use retrofocal designs for fast normal lenses, this tendency is more pronounced.

All in all, 99.99% baloney is probably an over estimate, but somewhere in the 90's is fair.

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