Hi Skip:
<< Well Gary, It looks like the LUG has been beating up your testing
methodology a bit this week. I hope you have your vest on. They're
quite
a contrary and Solms-centered bunch over there. In general, they don't
have much REALLY good to say about anything else except the German
glass.
Look here:
http://mejac.palo-alto.ca.us/leica-users/v20/topics1.html
The thread is entitled: [Leica] OM vs. Leica Lens tests, was How
good/bad/terrible is the R4?, on Aug 21
Keep on with your efforts, we all appreciate them. >>
I've been told about this thread by others, also. Funny thing is that
those who criticize the methodology have never previously contacted me.
Every methodology will be plagued by limitations. That, in itself,
shouldn't prevent someone from doing it, if the methodology is rooted in
the scientific method. Just evaluate the results within its limits.
Furthermore, how many people who think they have better methodology ever
finished the effort, like I have by tested every infinity focusable OM
System Zuiko? Or, have those who have tested all the Leica / Nikon /
Canon (insert favorite brand here) glass, put a few Zuikos and others
into the mix?
Yup, the Vario-Projar is a bit low in contrast and the corners aren't
the best at resolving power, but I consistently used it throughout the
tests, so that confounding factor was held constant. It's better than
almost all Kodak projection lenses and matches the resolution of the
original Leitz Colorplan 90mm f/2.5, although lower in contrast. Sure,
I could redo all the SQF evaluations using my new favorite Kodak Ektanar
102mm f/2.8 C. But if I remained within an A+ to D grading scheme, I'd
still have the same relative differences in SQF grades between any two
lenses, because I made the jumps from A to B to C to D visually equal in
difference.
Fujichrome 64T not suitable? Hum, that is like saying Panatomic-X wasn't
suitable for Modern Photography to use because anyone worth their salt
would be using Technical Pan because it resolves more. Since Technical
Pan wasn't around for most of the period Modern was testing, maybe they
should have used H&W Control VTE Pan? Egads, pick something closer to
what the world is using. I held the film type constant, so I eliminated
that confounding factor, too. I picked a color tranny film with a speed
slow enough to assure detail but not so slow that few would use a film
in that speed class (witness the demise of Kodachrome 25). A Type B
film isn't mainstream, but a 64 speed was - at the time of most of the
tests. And I had to use a Type B film due to my lighting setup. 100 is
now mainstream among persnickety users and 200 among general amateurs,
as per the PMA 2000 market survey.
I did bad science? Hum, 25 years as a research biologist taught me
something about the scientific method. The number one and two things
for me were to minimize noise in the data (confounding factors) and have
reproducible results. And the third was to match the test method to
something real world. Microfilming topographic and geology maps and
aerial photos were the most demanding applications of my Olympus OM
equipment, ever. So I stuck with something I knew and have done well.
If my tests favor lenses with flat fields, so be it. Anyone is welcome
to do the tests over with a curved subject. I sure get a peace of mind
in knowing that what I'm focusing on - anywhere on the screen - is what
will be in focus on the film!
The projections were onto a flat white board or poster paper. I
refocused the projector lens as appropriate, so curved slides weren't an
issue. I would have liked to have prints, but I'm not a rich man!
Plus, you have the effects of slide curvature in the enlarger negative
holder!
The 90mm f/2 APO-Summicron results point to something important for me:
peep hole focusing of a telephoto lens on a Leica rangefinder body isn't
something I consider easy. Especially in a model with a low base
magnification. I did have the body and lens checked out on a vertical
autocollimator to assure perfect infinity focus. I didn't use a
focusing aid on the Leica eyepieces and I did use a Varimagnifinder on
any SLR camera body (including all the OM lests) which would accept it.
A Varimagnifinder and a 2-4 screen makes for a very satisfying
combination - one which will leave the user assured they have acheived
critical focus, assuming the body and lens are in calibration, the
dioptric correction is correct and the lens attains in the center of the
field a B- or better grade wide open (which results in fine detail
shimmer). I repeated the APO-Summicron tests because I though I might
have misfocused. I didn't - the results were the same.
Rangefinder camera loose their focus accuracy advantage over an SLR in
the 90-135mm range, depending on the distance of the rangefinder
windows. The 135mm Bronica RF lens has now been dropped because they
couldn't get sufficient tolerances in the rangefinder cam to assure
accurate focus. The 90mm G-Sonnar I tested on a Contax G2 gave very
poor wide open results and I think it was a case of the electronic
rangefinder being at the limits of its accuracy ( I tried two different
bodies and two different lenses).
I lusted after a Leica along with the best of them. I cut my eye teeth
on a Canon IVS2 and VT system. But it isn't a satisfying experience to
actually use them. I gravitated to a bright line axillary viewfinder
for landscape work. When I finally saw an SLR image through a Nikon F
and an Olympus Pen F, I switched for ever. I demand a WYSIWYG
viewfinder and the 970f field you get in an OM body, plus accurate
macro framing, is just my cup of tea. Oh, and getting a recalibration
of a rangefinder mechanism? How many of us can afford the way Leica
does it: your technican sends them the old mechanism as a trade in for a
rebuilt one. Ouch$ Even the Canon cost me more than I afford at the
time.
If anyone wants to post this rejoiner to the LUG, be my guest. Like
Michael Johnston, who also got flack on the LUG, I've been fortunate to
use most every camera there is. The Olympus OM System won out and I
have no plans on changing till the day I die. It grows on you like a
cherished wife. And the best part is that she has inner beauty that
doesn't come with the pitfalls of a "trophy wife," which is always the
subject of comparisons and lust. You can even build the system and
still have disposible income, which is important towards purchasing the
items which might otherwise rob your images of their power. Such as an
excellent projection lens, top notch film scanner, fine enlarger and
enlarging lens, etc., and film to shoot, shoot and shoot till you get
good. It's always been a matter of cost/performance with me. Our wants
never seem to end, but if we buy with cost/performance ratios in mind,
we'll get more for our money.
Gary Reese
Las Vegas, NV
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