[Leica] new 75mm M lens

[henningw at archiphoto.com (Henning Wulff)]

It takes a rather large amount of effort and 
expense to get rid of spherical aberration, which 
is the main cause of focus shift. The problem is 
that if you just try to use aspherics to get rid 
of spherical aberration at long distances you are 
likely to get overcompensated spherical 
aberration at some distance and apertures, and 
that is one of the main causes for nasty bokeh.

This lens is supposedly based on the old Heliar 
design from Voigtl?nder of old; mainly the large 
format lens designs that were the classic 
portrait lenses of their time. These had a 'glow' 
which was very appealing, and the focus shift 
could be dealt with by re-checking the focus 
after stopping down. It was never that serious, 
and since pixel peeping had not yet been 
invented, often went unnoticed.


At 1:30 PM -0700 8/20/10, mehrdad wrote:
>tom a mentions about a glow wide open , which i translate to focus shift.
>all the latest cosina lenses have focus shift syndrome, i wonder why! and
>leica is getting away from it as fast as they can.
>On Fri, Aug 20, 2010 at 12:37 PM, Henning Wulff 
><henningw at archiphoto.com>wrote:
>
>>  I had a chance to play a bit with Tom Abrahamsson's copy of the lens. It
>>  looks very nice, and seems a bargain at the likely price of $7-800US. 
>> It's
>>  about halfway in size and weight between the 75/2 and 75/1.4 of Leica's. 
>> The
>>  hood is not built in, but can be reversed with a unique screw in/clamp on
>>  two part design that seems a bit fiddly.
>>
>>  I didn't do any rigorous testing, but it seems more like the Summilux in
>>  character and would make an excellent portrait lens, hence 'Heliar 
>> Classic'.
>>  It seems very sharp though at f/1.8 with very pleasing bokeh. It seems to
>>  have some focus shift, just like the Summilux, but it's very little.
>>  Unfortunately, like the 75/2.5, it only focusses to .9m.
>>
>>
>>
>>
>>  At 5:17 PM +1000 8/20/10, Geoff Hopkinson wrote:
>>
>>>  For anyone interested a friend of mine is the local distributor for
>>>  Voigtlander products and he has just released details of a new 75mm M
>>>  mount
>>>  lens in their range. You can read the detail on his blog here.
>>>
>>>  http://mainlinephoto.wordpress.com/
>>>
>>>  Cheers
>>>  Geoff
>>>
>>
-- 

    *            Henning J. Wulff
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