Hi!
g> 1. Price, redesigning the lens to be more economically manufactured with
g> automated machinery.
Tom, I fail to see how optical formula can be of importance here. I
can see that going from M to A and introduction of electronics in the
mount had caused change of lens internals. But not opti
Hi!
Rac> Looking at it from the other side, I'd speculate that more
Rac> has changed optically from series to series than has stayed the
Rac> same. Only the 50mm's seem to retain a direct heritage to the
Rac> original screwmount Takumars.
Bob, is it correct to understand your reasoning, part of
Well, there are 3 reasons that Pentax or anyone else would change optically
formulas.
1. Price, redesigning the lens to be more economically manufactured with
automated machinery.
2. Size, as with the M lenses, the whole thing could be made more compact. BTW,
AFAIK no M lens is the same formul
Boris,
Pentax has a long history with lenses back into the '50's.
Designs have been changed over time, often gradually.
Some of the evolution can be seen in the old screwmounts.
They had manual diaphrams, cocking diaphrams, semi-auto, and full auto.
The underlying optical designs changed as well,
Boz's site is a good starting point for research, but be warned that some
people on this group think that although two lenses may appear to be
optically indentical (apart from coating) in fact they may be different.
This is certainly possible, especially if the dimensions differ
considerably.
Hi!
On the time line first we M42 lenses, then K lenses, then M lenses,
then A lenses, then F lenses, then FA lenses. So far so good ...
There is something that confuses me. Let us take for example 50/1.7
lens. As far as I understand the optical formula is precisely the same
through M, A, F, FA r
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