[net.rec.photo] question about super speed lenses

phr@ucbvax.ARPA (Paul Rubin) (09/26/85)

It sounds like there are serious technical problems with making a sharp
super fast lens fill the 35mm frame, as well as size, depth of field etc.
The problems must be even worse for larger formats: 85mm f/2 is a standard
35 lens, but 85mm lenses are usually f/2.8 for 2 1/4" cameras.  However,
f/1.4 lenses with 10-to-1 zoom ranges are easy to find on 8mm movie
cameras.

Question: why don't camera makers offer super speed lenses on subminiature
format still cameras?  The Pentax 110 SLR is a cute toy with its 24mm/2.8
(or whatever it comes with), but with an f/1.0 or faster lens it would
make available darkness fans such as myself wake up and take notice.

mls@ittvax.ATC.ITT.UUCP (Michael Schneider) (10/22/85)

> The problems must be even worse for larger formats: 85mm f/2 is a standard
> 35 lens, but 85mm lenses are usually f/2.8 for 2 1/4" cameras.  However,
> f/1.4 lenses with 10-to-1 zoom ranges are easy to find on 8mm movie
> cameras.
> 
> Question: why don't camera makers offer super speed lenses on subminiature
> format still cameras?  

There are two problems to making such lenses.  First, as you indicated making 
a lens with a larger circle of focus is more difficult that one with a smaller
one.  Just anyone who has looked for view camera lenses and planned to use
the movements to the maximum.  For a submini, this is not a problem.  However,
if you look at movie camera lenses, you will find that they are not as sharp as
still camera lenses; they do not need to be due to subject motion etc.  Thus,
while it is possible to make 8mm zooms with f1.0 lenses (Cannon 310 had one I
think), the quality may not be good enough for a still.

M.L. Schneider

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