In searching for a small 90mm alternative to my Canadian 90 Summicron I've noticed that there is some variation in how Leica lenses transmit color. The first two lenses I bought were the 90 and a Canadian 21 Elmarit. These two lenses are distinctly warmer (yellow, not red or pink) than my Midland 7-element 35 Summicron, or any other lenses I've tried (50 'cron, 90 Elmarit-M and Tele, 135 TE, 35 ASPH 2 & 1.4, 28 2.8). The color difference is about equal to 1/2 of an 81A filter, but there seems to be a UV-blocking component as well, because the 90/21 absolutely strip away Velvia's tendency to go violet, especially up here at 5,280 feet (and higher).

In an earlier post someone also mentioned that the Noctilux is yellow-warm and that this was because Leica had used a UV cutoff glass in the design simply because the refractive index fit the requirements.

Anyway, I am curious to know whether the pre-APO/ASPH 90 f/2 and 21 f/2.8 do in fact contain UV-blocking glass that is not used, or used less, in most of Leica's other lenses.

Or is there some other difference? Once upon a time I remember a rumor that Leica used a Black Forest pine resin that absorbed UV as a cement for lens elements.

Any thoughts?

-- Andy Piper (apidens@denver.infi.net), May 21, 2001

Answers

Leitz (and now Leica) has used UV-inhibiting cement since the mid- 1960s. I don't think UV transmission is the difference.

-- Douglas Herr (telyt@earthlink.net), May 21, 2001.

One of the selling points of Leica glass is the uniform (anad quite neutral) color rendition across the range. Compared to Leica, my Nikkors seem to have built-in 81a's. All the lenses you describe I have used at one time or another and never noticed any difference in color rendition. Even those R lenses which were/are subbed out have had their coatings specified to keep color rendition as much as possible "in the family". Particularly with Velvia (a very high- contrast reversal film with very warm balance and quite susceptible to exposure-related color shifts) and the 2 lenses mentioned (1st version E60 Elmarit and 90/2 pre-APO, both of which show marked contrast changes through the widest 2 or 3 f-stops and are at opposite focal length poles--teles being much more susceptible to UV- induced blue casts in distant scenes at high altitude) I would have a hard time saying with confidence that the perceived warmth is related to UV absorption characteristics.

-- Jay (infinitydt@aol.com), May 21, 2001.

Leitz/Leica lenses use Canadian balsum, a resin from fir Abies balsamea as lens cememt, it has the property of cut off UV light and pass through other spectrum.

-- martin tai (martin.tai@capcanada.com), May 21, 2001.

Canada balsam hasn't been used in decades. Modern optical cements are cured by narrow-spectrum UV light, similar to the bonding process that dentists use, and are much more resistant to expansion/contraction and separation than the older cements.

-- Jay (infinitydt@aol.com), May 21, 2001.

My 90TE had the same Leica-neutral color cast as my brand new 90 APO asph.

-- Jack Flesher (jbflesher@msn.com), May 23, 2001.

On distinct characteristics of all Leica lenses(prime and zoom) is no infrared index mark.

-- martin tai (martin.tai@capcanada.com), May 27, 2001.

Leica glasses from Hoya

-- martin tai (martin.tai@capcanada.com), January 04, 2002.

Leica has long maintained that their lenses do not require the use of a UV filter (except for lens protection) because the UV radiation is effectivelt absorbed (whether by the cement and/or glass types used). I have no reason to doubt this. Apparently, some current Leica lenses do have a slight warm bias (50/1 Nocti, 35/2.0 and 1.4 ASPH), but this bias is very slight.

In actual practice, you would have to do carefully controlled comparison testing to detect any color bias, for several reasons. Many of today's slight films have color biases built in, including warmish rendition of some Ektachromes, increased color saturation in many films (especially Velvia), greenish bias in some of the Fujichromes, putative reddish bias in Kodachrome, etc.

Besides potential biases built into the slide film, daylight films are balanced for "sunlight" (color temperature 5500 K). Any deviation in the actual ambient light temperature would result in images skewed slightly toward a warmish or coolish rendition. Believe it or not, open shade from a blue sky can result in an effective color temperature as high as 8500-9000 K. This would result in a significant shift toward blue, which would result in very cool skin tones.

Practically speaking, I wouldn't worry about the color rendition of Leica lenses, since any inherent bias is l;ikely to be offset by larger effects due to film type and the characteristics of the lighting.

-- Eliot (erosen@lij.edu), January 07, 2002.