[Leica] Image circle

[red735i at earthlink.net (Frank Filippone)]

There is a caveat in the measurement of the image circle.... and is the
reason specmanship can be played.....or results can be different....

The circle is defined not by the absolute diameter of the circle of the
image when it goes from image to black, but some subset.. dependent on
distortion, vignetting amount, and who knows what else.  It is all about the
quality of the image at that radial location.
This was a classic argument for Schneider and Rodenstock in LF lenses....
they had different criteria for image circle.

So when Mr. Karbe says the image circle of the S2 lenses is just big enough
for the 45mm sensor, that will include some caveats compared to some user
putting the lens to a Ground Glass and measuring it himself....

Frank Filippone
red735i at earthlink.net

a circle is a circle , how comes it has to be corrected?

Ph


> FWIW all of the M lenses produce an image circle sufficient to cover  
> all of
> the 24x36 mm rectangle and Peter Karbe (Optics department head at  
> Solms)
> recently said that the S system lenses provide an image circle  
> sufficient
> for that camera's 30x45 mm sensor (but no larger)
>