[Leica] Back focus distance

[rangefinder at screengang.com (Didier Ludwig)]

Charles

The shorter backfocus, ie. the lack of needing a retrofocal design, has 
always been an benefit for the rangefinder lenses. But a lens is not better 
just because of the shorter backfocus, it's  smaller and compacter (which 
isn't that bad, too...). So this article does not really tell something new 
to us. 

But of course the shorter backfocus is a benefit for a prosumer digi camera 
like the Sony DSC-R1 because it makes it a bit compacter, too. But 
personally, I prefer even the dimmed tunnel-view of a dslr pentaprism to one 
of those eye-fatiguing LCD viewer. So it's true the digital M still has a 
chance.

But it is a known fact that digital sensors like the light coming in 
parallely with an angle as close as possible to 90 degrees to the sensor, a 
rule which is difficult to realize with super wide angles and short 
backfocus. 

It will be interesting to see some more Sony DSC-R1 24mm wide angle/wide 
open sample shots as I'm curious about it's vignetting. At least, this 
sample here  http://tinyurl.com/a59hd with f=8, shows absolutely no 
vignetting to me.

Thanks for the link,
Didier



>I came acrossed this at
>http://www.imaging-resource.com/PRODS/R1/R1A3.HTM seemed to
>be relevant to the whole M8 digital hope ....