[Leica] Was M9 internal IR Cut filter - 21mm on M9

[Frank.Dernie at btinternet.com (Frank Dernie)]

Hi Howard,
all Leica WA lenses have been slightly retrofocus since around 1980. I do 
not know whether this was to reduce natural vignetting or to allow more 
accurate TTL metering, perhaps both. WA lenses since then will probably work 
well on the M9, earlier ones need a trial I suppose.
FWIW the only lens I have used on my M9 that does not return impeccable 
results is the CV 12mm, and IMO if that needs corrections it is right and 
proper for Cosina to provide them, not Leica.
cheers,
other Frank

On 20 Dec, 2009, at 00:41, H&ECummer wrote:

> 
> Hi Frank,
> Just to add to the info pool - I used the 21 Lux on an M9 at the LHSA 
> meeting in Seattle and the combo worked fine.
> Don't know how retro focus the 21 Lux is?? Not at all???
> Cheers
> Howard