FYI friends, In last months Colorfoto (12/2001)magazine, the Leica 2.8/100 APO Macro was rated with the highest total score ever recorded by the testers using their new standards. The lens scored 90 out of 100. It should also be mentioned that the Minolta 100mm Macro APO tied the Leica with 90 points. I will post the details regarding the score now:

Sharpness 24 out of 30, Contrast/Brilliance 27 (30), Centering (construction test) 20 (30), Distortion 10 (10). The Minolta beat the Leica by one point in Contrast/Brillianz, but the Leica beat the Minolta by one in Centering.

-- RedCave (redcave@schweiz.com), January 11, 2002

Answers

Another German photography periodical usually gives high scores to lenses that appear as 'dogs' by Colorfoto testing, and vice versa. First, only one sample is tested. Then, the engineers/journalists have their own preferences, which subconsciously influences their precision in mounting the lenses on the test bench. And we haven't even gone into the effects of advertising budgets.

-- Oliver Schrinner (piraya@hispavista.com), January 11, 2002.

"which subconsciously influences their precision in mounting the lenses on the test bench"

Oliver, your point is well made and taken, but if we bring the subconscious into the consideration of science, then everything is up in the air!

-- rob (rob@robertappleby.com), January 11, 2002.

Oliver,

do I remember right or was this the lens you intended to buy ? If yes, what is your experience ?

Kai

-- Kai Blanke (kai.blanke@iname.com), January 11, 2002.

Does anyone know if the tripod collar is still available for the 100 APO-Macro? I tried one just mounted on the camera and it wouldn't hold steady enough for me.

-- Jay (infinitydt@aol.com), January 11, 2002.

Jay - the removable collar is the STA-1. I think it's still available. I find on the 100 it's really usable only when you rack the focus out a touch. In other words, questionnable for use at infinity.

The STA-1 more convenient on the current 180 APO. Much better balance & fit.

On the 80-200 the STA-1 kind'a fits, but not very well due to clamping over the red mounting index bump.

-- Ken Shipman (kennyshipman@aol.com), January 11, 2002.

Rob, the role of the unconscious, that is, of experimenter bias, is acknowleged and controlled for in many scientific studies. This can be done by blindfold or double-blind testing. For example, in drug efficacy tests, neither the patient nor the experimenter administering the meds knows whether it's the active drug or the placebo that's being administered to a given patient. The meds are secretly coded so that only a third party knows which is which, and it isn't revealed until after the results are tabulated. That's how the double blind works.

There's a scientific procedure that could be useful to photographers. If we wanted other to judge which of two pictures are sharpest (or whatever) we could present them in an A-B-B-A order. This is called counterbalanced order. A is presented first. Then B is shown twice in a row. (the subject doesn't neccessarily know this). Finally, A is presented again. This balanced out any experimental error that might be induced by the order in which the two are presented.

So whenever the response of a human is part of the experiment, science provides a means to control for error. Not so, though, for paranormal stuff, like communicating with the dead, ESP, etc. Science lacks a method for studying things which don't happen reliably.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 11, 2002.

You know, the 24 out of 30 for sharpness doesn't seem too impressive for an APO. 20 out of 30 for centering sounds worse.

What gives?

-- Bob Fleischman (RFXMAIL@prodigy.net), January 11, 2002.

Bob, I'm aware of all that, don't worry.

-- rob (rob@robertappleby.com), January 11, 2002.

The 100mm f2.8 may use the STA-1 collar, but that is absolutely not a necessary item, even for critical macro work: even fully extended, the 100 is secure on the body, with pretty comfortable and secure balance (certainly with R8). Concentrate on the tripod and ball head instead.

BTW I have recently ad the opportunity to use the Minolta (and have extensively used Nikon AF and Pentax AF 100mm macro lenses in the past). All these lenses are of absolutely top notch optical quality, but none come anywhere near the Leica when it comes to precision and ease of focus. The throw and dampening of the Leica is absolutely perfect, both for 'normal' use and macro proper. That does not show in the Colorfoto "tests" of course.

Also other much more reputable tests have consistently shown the Leica 100 to be a visible step ahead of competition at f2.8, and, more importantly for a macro lens, at smallest apertures as well. Strange that the Colorfoto "test" does not rate that either.

-- Jacques (jacques.balthazar@hotmail.com), January 14, 2002.

Kai: given the Christmas stress, a colleague on holiday, and a few university exams, my photo gear's about to petrify. I.e., I haven't bought the Apo-Macro yet; I had the chance to use it, however, some time ago, and it was fantastic. No matter what tests say, it's probably the world's best short tele lens for SLRs. (The 90 AA may be a tad sharper, but that's splitting microfibres :-) Mechanically, it simply blows the competition away. The long focus throw alone is worth its price!

Bob and Rob: I wouldn't trust a 'scientific' test with human influence and without double-blind testing, and Colorfoto's information on their testing methods doesn't tell us about such verification. BTW, these thorough Germans actually do measure the lenses on an optical bench with calibrated instruments around, the lens being the only variable--but so does the lab employed by fotomagazin, which often rates those lenses as 'dogs' that came out as the best in Colorfoto tests, and vice versa. I stopped buying these periodicals long ago, but last time I browsed through them in a public library, lens test continued to show the described, err, pattern. They aren't that much better than Popular Photography & co.

-- Oliver Schrinner (piraya@hispavista.com), January 14, 2002.

Bob F.: Your point about the importance of correctly performed double blind comparative studies is excellent. However, basing all of your conclusions on only ONE lens sample from company X and company Y VIOLATES the spirit of this type of scientific testing. The results are uninterpretable at best. (8>))-- Albert

-- Albert Knapp MD (albertknappmd@mac.com), January 14, 2002.