[Leica] Portrait Lens: 90mm or 135mm?

[AppleMac97@aol.com]

Hi Everybody!

After 20 years of using SLRs (Pentax, Nikon and Canon) I finally succumbed to 
the Leica mystique and bought recently a new M6 TTL (0.72, Chrome) and a new 
Summicron-M 1:2/35 ASPH lens (Chrome).  Needless to say, after using 
auto-everything cameras all these years, it is a joy to use a fully 
mechanical 35mm rangefinder camera.  I shoot primarily slides and B&W film, 
and the quality of the Leica lens is amazing!  Comparing slides and negatives 
shot with my quite sharp earlier Nikon and Canon autofocus fixed focal length 
lenses to the ones shot with the Summicron, I can clearly see a higher degree 
of image quality - contrast, sharpness, color and saturation.  Just using the 
M6 is a wonderful tactile experience!  Winding the film and hearing the soft 
sound of the shutter is almost a religious experience!

I need your help in selecting a lens for portrait photography with the M6.  I 
am considering the 90mm/f2.0 APO ASPH and the 135mm/f3.4 APO lenses.  I can 
afford to buy only one of these lenses!  I would like to know what veteran 
users of these focal lengths think and recommend.  From time to time, I also 
plan to use the lens for landscape photography.  

Thanks in advance!

Muhammad Chishty