Re: [Leica] Leica-Users List Digest V3 #59

["Bryan Willman" <bryanwi@seanet.com>]

Charlie, you raise a good point.

However, when I've done lens tests (not very well, more to learn)
I always mount a camera on a tripod, and shoot the same scene
(often a test target) back-to-back in very rapid order.

This does allow you to say things like "lens a did better in this
test than lens b".  Of course, no person or animal has a face
as flat as a test target, so it's not necessarily a super applicable
test, but it does give some data.

Any test that isn't this sort of back-to-back comparision is hard to use.
Even numbers like LP/MM or MTF curves are hard to compare if they
weren't generated in controlled, comparable, circumstances.

It is no trick at all to find that the limiting factor on sharpness is NOT
the
lens.  It's holding the target totally still, focusing perfectly, etc. etc.

On the other hand, there has been a common believe that if you are
holding the camera in your hand all lenses are reduced to being about
equal, I have recent results that suggest that this is not true.  But you
must
study hand-holding technique.

bmw

- -----Original Message-----
From: Summicron1 <Summicron1@aol.com>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Sunday, May 17, 1998 8:25 PM
Subject: Re: [Leica] Leica-Users List Digest V3 #59


>re sharpness-- i read a lot of messages on this list about which lens is
>sharper, especially by people saying the new asph lenses are visibly
sharper,
>and i have to wonder:
>
>under what circumstances? are the comparison pictures just slides?prints?
what
>magnification? and most important, are the comparison prints of the same
>image, the same lighting, same film same processing, same same? I have seen
>situations where the same lens could not get a sharp picture, no matter
what
>-- usually flat lit scenes with not a lot of detail. high contrast scenes,
on
>the other hand, LOOK sharper, sometimes even when shot with a kodak
brownie.
>