[Leica] Re: Eric's comments on "normal" lenses

[rpalmier at depaul.edu (Robert Palmieri)]

Frank - 

Thanks for the post - as I recall you're one of those people who
actually knows quite a bit more than me about optics.

The reasons I chalked up the mediocre performance of my 50 'Lux to field
curvature issues are the following:

1. From the MTF curves that I have I would expect the performance at 5.6
to drop at the edges but actually improve somewhat in the corners; the
corners actually looked worse, and in landscape stuff the lower edge is
important to me all the way across.

2. My understanding of field curvature issues is that it's more of a
depth-of-focus problem (at the film plane) than a depth-of-field issue,
although increasing DOF by stopping down (as well as reducing
aberrations in general) certainly should mask the issue.

Soon will be the picture postings, although I've almost certainly tossed
the bad slides that put this bug in my bonnet in the first place, plus I
don't trust my scanner to accurately represent these kinds of things.

Bob Palmieri