[Leica] PAW - M8 Noctilux f/1.0 (was back focus...)

[tomschofield at comcast.net (Tom Schofield)]

Eric,

The back focus problem should be at its worst at f 2.0.  Although  
there is more back focus at 4 or 5.6, there is also more depth of  
field at those apertures.  You have two countervailing considerations  
-- back focus distance getting worse as you stop down, but depth of  
field getting broader and covering up the back focus error.  Erwin's  
and Leica's MTF testing  show the worst resolution loss (absent  
compensation by refocusing) at f 2.0.  That 's why I've suggested  
keeping in mind to focus on the nose instead of the eyeball at f 2.0.

Tom


On Apr 28, 2007, at 1:30 PM, Eric Korenman wrote:

> not to be a party pooper but:
>
> How about f /4.0 or f/5.6 at minimum focus?
>
> Eric
>
>