Archived posting to the Leica Users Group, 1998/12/14

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Subject: RE: [Leica] Contax & Leica
From: Andre Jean Quintal <megamax@abacom.com>
Date: Tue, 15 Dec 1998 00:05:09 -0500

At 20:05 -0600 14/12/98, Eric Welch wrote:
>>2 / Is there some "chart" or system to help rate
>>the ACUTANCE / EDGE DEFINITION
>>of a given lens, objectively ?
>>Or RELATIVE to others designs ?
>>Would this relate to some "threshold" point
>>in a M.T.F. curve, even subjective ?
>
>Do we care all that much when a negative is so large how "sharp" it is?
>Wouldn't there be more important corrections for minimal magnification
>increases of medium and large format compared to 35mm?
[ . . . ]
>Eric Welch

	I meant EVEN for 35mm (135) lenses ?
	Not just the "other" formats . . .

	Looking for acutance-specific info !

	In other words : is there a given, generally accepted
	point in A-N-Y M.T.F. curve,
	or A-N-Y OTHER type or set of graph(s), that de facto
	mean a guarantee, more or less, of a certain
	level of acutance / edge definition / "fidelity" / other
	positive "traits" of lenses that "makes"
	a given lens design or model a "classic"
	that represents an historical achievement ?

	Or some technical or engineering factor or value
	other than a M.T.F. curve that serves the same
	purpose : classifying lenses by general degree
	or level of performance, ACUTANCE-wise ?

	When performance gets stratospheric
	as LEICA lenses now can deliver,
	it's not such an obvious "thing" to DISCRIMINATE
	the DOMINATING model or design . . . on "specs"
	VS a technically oriented photo exhibition
	which would allow the more subjective appreciation .

	"Even then ..." may well be your immediate answer !

	Yet another way of expressing the question:
	would a LEICA connoisseur be readily and repeatably able to
	say: "This is a Summicron 35mm f/2 -ASPH - M shot"
	VS "this is a 35mm Summilux-R f/1.4 FLE shot"
	VS a non ASPH Summicron or Elmar or Elmarit shot,
	VS another famous "classic" LEICA design,
	a Noctilux perhaps,
	or some other LEICA lens model / focal
	per general "signature" and /or degree of excellence ?
	Or, for better or worse,
	even allowing non-LEICA originated shots in the picture ...
	[ Perhaps adding such a constraint as mandatory
	16" x 20" enlargements (for discussion purposes) ...
	from the same enlarger / lens combination, same lab technician
	and similar fresh photo-chemicals. ]

	Geared towards ISOLATING some abstract notion of optics based
	"ACUTANCE", specifically [ which i don't recall ever
	having read about (being ever in need of broadening
	my overall proficiency at "evolving" such an "eye"
	and photography related knowledge ) ] . . .
	Much as a "nose", who would instantly, or just about,
	call out various exotic high end perfumes...
	wines, beers. or whatnot ... : hybrid roses ..., printing inks ...,
	chocolates..., Dare VS Peek Frean cookies !

	Leica science VS Leica art !

	A. J. Q.

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