[Leica] 560mm f/6.8

[telyt at earthlink.net (Douglas Herr)]

And I am finding the high-ISO capabilities of the DMR make the 560 
f/6.8 even more useful than with film.

Doug Herr
Birdman of Sacramento
http://www.wildlightphoto.com

On Jan 11, 2007, at 8:10 PM, grduprey@mchsi.com wrote:

> Larry,
>
> It seems to do a great job on my film R8 also.  The 560 Telyt is one 
> of my favorite lenses for bird and animal shooting.  Also have used it 
> for formula one shooting.  Great lens with very sharp performance.
>
> Gene
>
>
> -------------- Original message from Lawrence Zeitlin 
> <lrzeitlin@optonline.net>: --------------
>
>
>>
>> On Jan 11, 2007, at 6:23 PM, Len wrote:
>>
>>> Thanks. I have the use of it (Telyt 560/f6.8) for the weekend along
>>> with a R8 body. I
>>> still find it hard to believe a simple 2 element lens can be that
>>> good.
>>
>> I have a friend, a professor of optical physics, at the University of
>> Rochester who insists that the sharpest long focal lenses have the
>> fewest elements. The Telyt lens only covers a field of 3.5 degrees on
>> a 35mm frame, 4.5 degrees on an M8 frame. With that narrow a field
>> you don't need to worry about all the aberrations that multiple
>> elements are required to correct. In fact, if you used a narrow band
>> pass filter, a single element lens would be almost ideal. Obviously
>> Leitz engineers agreed and the results confirm the theory. We need
>> the multiple element ASPH designs because we insist on short focal
>> length fast lenses for multicolored subjects at close ranges.
>>
>> The 42" Yerkes telescope, the biggest refractor telescope in the
>> world is a two element achromatic.
>>
>> Larry Z
>>
>>
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>
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