¡>Dear list,
>
>I recall that range finder design of no mirror makes it possible to attach
>the lens with its rear element very close to the shutter. This, I was told,
>benefits the design of wide angle lenses. As such we have Hassy SWC, which
>is a body designed for the lens, and probably that's why rangefinders such
>as M6, G2 and Hexar are still in demand.
>My questions:
I think that these questions are off-topic, but I will try to explain.
>What really is the benefit of being able to put lens as close as possible to
>the film (shutter)?
In order to focus to infinite, the rear principal point of the lens must be
at one focal length from the film plane.
>Is it simplicity of designing the lens ?
That's the answer, I think.
In a easy to design lens with few elements (I will call it a standard
lens), the rear principal point is inside the lens, so, using such design
in a wide angle will block the mirror movement.
In order to design a wide angle lens for a SLR, you need to put the rear
principal point outside the lens, so you need to use a more complex lens
design (retrofocus).
>or is there a natural law prohibiting
>certain quality if the lens is placed longer than certain distance from the
>film?
Don't think so, but, with a given optical technology, the standard design
will alyays be easier to correct for aberrations, flare, and so on, so the
retrofocus will be always worse.
You can, of course, design a standard lens that is worse than a given
retrofocus one.
But higher quality from wide angles is not the only reason for choosing a
rangefinder.
Size, sound, viewfinder brightness and trepidation are also important.
Hope it helps.
Vicente
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