[Leica] The great 280 debate

[Nick Hunter <nhunter1@mindspring.com>]

From Eric Welch:

>Leica also chose to go with 280mm for the name I'll bet because with a 1.4
>converter that was created for it would make it exactly 400, instead of
>420mm that people think they were getting with Nikons and Canons.


The 280 focal length for leica goes back to 1961 when Leitz filled in the
gap between 200mm - 400mm with the original 280/4.8 visoflex lens. This was
before teleconverters were common-none in the visoflex system.

I think Leica thought the lenses should be spaced evenly by magnification,
and 280 is halfway in that respect (not 300).Each of their original series
(135-200-280-400-560-800) that evolved from the 1930's - 1960's is about
40% different from the next. (actually, sq. root of 2) This is similar to
the progression of f-stops (1.4-2-2.8-4-5.6-8) and based on the same
arithmetic. Of course, this means that when 1.4 converters arrived, the
extended focal length remained in the progression.

Eric, please note: I'm not disagreeing with you, I'm just pointing out that
the focal length progression that Leica uses today predates the use of
converters, although that may be why they continue to use those lengths.

BTW 180-250-350 is also a 1.4 times progression, although these lenses are
slightly out of step with the others.

Nick Hunter