Super-wide on M6...Opinions, please

[Wolfgang Sachse <sachse@msc.cornell.edu>]

Hi Group -

I want to buy a lens whose field of view is between my
360-deg panorama and my 84-deg, 24mm Nikkor. I am looking at
either the 21mm (Super Angulon or Elmarit) for my M6 or the
20mm/f2.8D for my Nikon. I'm prompted to post this here
because of the number of persons who have experience with a
super-wide lens on their M-cameras.

My applications:
	Close-in (1 to 3 meters away) action photography,
	typically black & white. Flash will likely NOT be used.
	A secondary application, sweeping landscape photographs.

One being a SLR-system and the other a rangefinder, here's
my list of comparison features. Can users of the 21 Leica
lenses please comment. Thanks.

The lenses:
^^^^^^^^^^
  21 mm/f3.4 Super Angulon; 21mm/f2.8 Elmarit; 20mm/f2.8D Nikon

1. From all the information that I can gather, all three of
	the above lenses are optically excellent.

2. The use of these lenses and their associated cameras are
	of course different. The Leica system has the short-delay
	shutter and quiet operation; the SLR has all that whirring,
	clunking and winding going on. But OK, I can live with that.

3. The Leica lenses require the use of an external viewfinder
	though focusing is through the built-in M6 viewfinder.
	SLR viewing and focusing is through the lens.

4. The Leica optics are mechanical focusing and aperture settings
	the Nikon can be used in autofocus and aperture mode. But
	to me this will probably not be a handicap or problem. It
	might be for some users/applications.

	Focusing with the Leica lenses would probably be easiest
	to achieve by setting the focus on the lens and just
	shooting. The Nikon has fast autofocus capability.

5. When I began checking into the difference between the two
	leica optics, a dealer told me that the Super Angulon
	was a bit better for black & white photography and
	the Elmarit a better choice for color. Is this true?

6. The use of filters (polarizing) on the Leica lenses is a bit
	problematical. No problem with the SLR.

7. The Leica lenses cost about 3+ times that of the Nikon lens.

8. The Super Angulon is a bit slower (f3.4 maximum aperture)
	compared to the other two lenses (f2.8 maximum aperture).

9. Because of its construction, the Super Angulon does not permit
	the use of the TTL exposure system of the M6; the Elmarit
	does.

10. More...?

I would be delighted to hear from other users of wide-angle
optics wtheir experiences/opinions/thoughts/anything
regarding any of the above lenes. Many thanks.

Best wishes,

- -- Wolfgang

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    Wolfgang Sachse                             Cornell University
    sachse@msc.cornell.edu      http://www.msc.cornell.edu/~sachse
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