Re: [Leica] Testing notes and questions.

[henry <henry@henryambrose.com>]

>
>	1.  When you are tesing a 21mm lens, is there a customary distance
>(say, some multiple of the focal length) at which you check for fine
>detail rendition?  Usually, I shoot at a skyline with varying distances,
>and the way I judge lenses is by the smallest thing (like, say a facade
>brick or a limestone caulk seam) that comes out.  This seems to have
>failed me with 21s, since it seems that what I normally use to check
>overall quality are now smaller than film grains.
It would seem to me that a test at the distances that you personally are 
going to use the lens would be in order. So, if you do landscapes of 
distant scenes then maybe thats a good way to test, but keep in mind you 
have may LOTS of atmospheric interference and variablility each time you 
do a test.

Do you make all (or even a lot) of your pictures at infinity?
>
>	2.  For people who heavily shoot 21s, is the game just to focus on
>something in the foreground and let everything else fall in?  I am
>beginning to get the idea that slavish devotion to focusing at infinity
>wastes the DOF on objects too small to render well on film.
I have the 24 ASPH and use it for photographing people at very near to 
maybe as far as 20 feet away. Mostly near as in minimum focusing distance 
to maybe 2 meters. What a lens does at infinity for me just does not 
matter al long as its not ugly. But from lots of everyday use the 24 is 
simply great at any distance.

If you make all your pictures at infinity then it would seem wise to test 
there.
Otherwise why do this??? I'd test mine at my working distances.
>	3.  Can someone recommend the finest-grain development regime that
>keeps TMX's speed at 100 and its curve as straight as possible?  I usually
>use hyperdilute Rodinal or 1:1 Xtol, but the former changes the toe and
>shoulder, and the latter may be too grainy for testing lenses.
TechPan in Technidol.
Its touchy, but it is the VERY best choice for testing. IMO

Or, if thats too much trouble then Velvia is a good film and you can get 
consistent processing without bother. TechPan is better though.

Bracket your focus and bracket your exposure (by speed, not aperture) 
whatever film you use.
>
>Testing Notes:
>
>	1.  I just got finished running identical tests with two bodies
>for focus and RF operation, using an M3, a Hexar RF, a 21 Kobalux, a 35
>Summicron, a 50 Hexanon and a 90 Hexanon, using all lenses on both
>cameras, shooting from 2.8 to 16 on all of them.  RF alignment was
>absolutely identical between both.  I will report back on whether one
>body produces sharper pictures than the other.
>
>	2.  Hexar metering - for the M3 shots, I established an exposure
>of f/16 and 1/30 (and equivalents) by using a Zone VI spotmeter on the
>street and setting the street to Zone V.  When I reshot all of the tests
>with  the Hexar, AEL produced this same basic exposure with all four
>lenses,  and did  not deviate at all.  This was true even with the
>non-retrofocus 21.  So is  this oft-discussed superwide metering problem
>just with the M6?  Or is  there some circumstance in which both cameras
>would fail to meter correctly?  Is this a problem with the CL/CLE?
If you mean the superwide metering problem with M6s, I think you are 
talking aobut operator error. The camera only meters what you point it 
at. With a 15 you are guessing about what the camera is seeing or its 
seeing so much that you have a hard time understanding what its seeing.
>
>Have a great day!
>Dante
>
Henry