[Leica] Mike's new religion

[Erwin Puts <imxputs@knoware.nl>]

Mike J wrote in part:
" ...Or, in other words, you know full well that you cannot tell a print
>  made with a Leica lens from a print made with a Pentax lens. And you are
>  absolutely correct in that assumption, I believe.
>
>  Any other response would have made me very surprised. Any lens expert
>  knows that you cannot tell one brand of lens from another based only on
>  real-world results"

Well Mike: yours is a fine example of semantic armtwisting and 
logical juggling. I said that your test is flawed, not in principle 
but in execution. Your inference that by stating this I do 
acknowledge that I do know that it is impossible to identify prints 
made with a certain camera/lens combination is  a strong leap of your 
imagination. And not justified I am afraid to say.  Your  gauntlet 
test is set up to prove a hypothesis, that is what every test tries 
to do. Now simple and time honored test procedures that are conducted 
all over the world, give you the rules. Any test should be done in 
such a way that only the variable you have identified as proving the 
hypothesis should be the real and only variable. All other 
influencing factors need to be kept constant or under control. 
Secondly a control group with a placebo environment need to set up to 
ascertain the validity of your setup. And most importantly: the 
person designing the test should predict before the start of the test 
what results are required to prove or disprove the hypothesis. This 
prediction has not been published, making the test a -see-I-told-you- 
exercise.
The most misleading of your setup is the generality of your 
hypothesis, that is: "you cannot tell a print
made with a brand X lens from a print made with a brand Y lens". That 
is you assume that a picture made with a 180mm lens at f/2 of brand X 
cannot be told apart from a print made with a 35mm lens at f/8 of 
brand Y? Your only selection criterium is the sharpness criterium 
which is as subjective as can be.  This is a most unrealistic 
assertion and shows that you are not really focused on a true and 
meaningful test. Your mind is already made up: yours is not  an 
interesting hypothesis, but already a statement of fact as you have 
said above in the quote. Now it is very easy to conduct a session 
that will prove you "right".  Show a group of persons ten prints 
selected by the one who wants to prove himself right, include three 
pictures made with brand X equipment  among the ten and here we go: 
if 25% of guesses by the group of test persons correctly identifies 
the brand X picture is your hypothesis OK. Or do we need 53% to make 
the test meaningful. How big is the mere statistical chance that x% 
will at random select the correct print?
I am amazed, Mike, that you go to these lengths just to 'prove' your 
point which is unprovable to start with. I did on purpose refer to 
the "angels on a pin" discussion. When we are talking religion and 
that is what you are doing all arguments and facts are futile. What 
you want to get is support  for your own belief system and values. 
Which is fine with me. But I graciously decline to be converted to 
your religious beliefs.
Your second statement ("Any lens expert knows that you cannot tell 
one brand of lens from another based only on real-world results") is 
again one of those sentences that look charmingly convincing but are 
basically non substantive, like this one: "any political forecasting 
expert knows that you cannot tell which candidate for president will 
win the election based only on real-world results".Well it is the 
charm of any attractive religion that people can repeat mantras that 
are simple to remember and evoke the impression of deep significance. 
Our language is a powerful instrument is it not?

Erwin