Quo Vadis Nex?

Started May 16, 2011 | Discussions thread
rrfischer
Regular MemberPosts: 232
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Re: Quo Vadis Nex?
In reply to gfrensen, May 16, 2011

gfrensen wrote:

Well YES when you want a fast lens you need large glass surfaces, so larger lenses.

Then to give a large FL the front lens has to be at a given distance from the sensor, nothing can be done about that ( or you have to make a miror lens or a colapseble one).

Distance of the front glass of the lens has nothing to do with its focal length. On a pin hole camera, the pin is at a distance from the film equal to the focal length. When you place a lens in front of the film, then the focal length is the distance from the film plane to a point where the light converges, which is also dependent on the shape of the lens. I guarantee you that my cheap Kalimar 500 mm refractor (not reflex) lens doesn't have half meter of length (about 35 cm actually, counting the registration distance).

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