Archived posting to the Leica Users Group, 1997/12/05

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] Only two diffraction limited lens?
From: "BIRKEY, DUANE" <>
Date: Fri, 5 Dec 1997 9:35:47 -0500

At 11:00 PM 12/3/97 -0600, Eric Welch wrote:
>As far as I know, Leica has only two diffraction-limited lenses. So 
>good are those numbers?

Uh , I was under the impression that all lenses are diffraction 
limited.   A matter of physics as I remember. The reason many 
manufacturers don't include f/22 or f/32 apertures on their lenses is 
the quality level suffers too much from diffraction at those apertures. 
 When you read lens tests they will often tell you that a lens reaches 
it's optimum at 5.6 or f 8.  I've always been under the impression the 
reason the lens did not improve after that point was that it was 
limited by diffraction.  

But, I've been wrong before. 

Help, Erwin, Help!   

Duane Birkey
HCJB World Radio
Quito Ecuador