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Question about these c-mounts (mainly CCTV lenses)- good and bad qualities

madmaxmedia

New member
Many of these lenses are very sharp and contrasty in the center of the frame wide open, but have significant deficits as well.

I know next to nothing about lens design, but was wondering about the properties of these lenses. I assume they don't have many elements inside, due to the designers simply not caring about flaring, chromatic and spherical aberrations, etc.

But not needing many elements in their design, is this why they are often sharp in the middle? Not a lot of complex glass to correct things, but since this is cheap glass anyway maybe this is a good thing as there's less stuff in the way. That's why I thought these lenses can be centrally sharp, unlike say really cheap consumer zoom lenses which are mediocre across the board, but do pay at least lip service in trying to moderate glare, aberrations, etc.

Here's one today with the Computar 12.5mm f/1.3 (at f/2 here). Not pin sharp or anything, but when conditions are not too challenging the flaws of the lens are reasonably restrained.
 
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