The myth of the white lens
Extending something I wrote about in passing, is this discussion which beats that old Canon horse: “Canon L lenses use white because they absorb less heat from sunlight—a purely functional, not cosmetic consideration.”
Is this true?
The physics of white
I’ve heard this argument many times before from Canon and Canon L-lens addicts. After all this time, it still sounds like a pile of shit.
The rumor is that it was because they use fluorite as the low dispersion glass of their lenses—that sounds like half bullshit. Calcium fluorite is a crystal so it will be more susceptible to thermal shock. But the trick is to trust the astronomers, does this sound likely?
Besides, how many Canon lenses still use fluorite as their low-dispersion glass? If any do, it sounds a bit silly: ED/UD/SLD glass has improved to have better optical properties than fluorite.
The real physics of white
Why did Canon paint their lenses white? I think it’s because solar observatories and telescopes were painted white in order to keep the air inside at a steady temperature during the day.
(Whenever you think photographers are obsessive, just remember that for astronomers, they have to be obsessive.)
The way I figure it, I guess the Canon guys saw that and thought to themselves, “white = astronomer telescope1 = big magnification” and a marketing legend was born.
Personally, white (with alternating black for the focusing and zoom rings) screams cheapness on a 35mm SLR camera. I much prefer the black with a nice gold ring accent. 
A favorite pasttime
One of my favorite things to do:
Someone: “I’m an astronomy major.”
Me: “Oh wow, that’s cool. I’m a Gemini, what are you?”
They love that shit, trust me. 
July 7th, 2006 at 2:30 am
Man, that last bit killed me. Love it.
July 7th, 2006 at 12:56 pm
@Tracer:
Thanks!
July 7th, 2006 at 3:57 pm
I for one thing they’re white so you can pick out the Canons on the side-line. Or you would be able to if they weren’t the dominant bodies in sport.
And my 24-70L has (2 I think) fluorite elements, but the lens is black, so I gues it chucks that idea out the window.
btw, I’ve seen camo covers for the white lenses, so they aren’t always appreciated. Nothing screams ‘rob me’ like a white lens.
July 15th, 2006 at 11:40 am
The problem solved by a white lens casing is exactly the one you mock. A black lens heats up at a different rate from the lens elements and other mechanical parts. There are little motors in there, and plastic and rubber parts that can melt. White adds longevity. Every long lens worth owning is a pale color for this reason.
Tamron made a ‘cammo’ color 300mm. It’s still pale green.
July 15th, 2006 at 4:29 pm
[...] Tamron made a ‘cammo’ color 300mm. It’s still pale green.” —commenter on a previous blog entry [...]
December 3rd, 2006 at 6:02 pm
[...] EF 70-200mm f/2.8L USM. You see an L and you know you’re going to pay for the nose. This lens is no exception ($1100 street. A Nikon photographer would be looking for an 80-200mm f/2.8 used. [...]
December 25th, 2006 at 12:53 pm
[...] A long time ago, it might have meant a fluorite element was used. This was probably in counterpoint the Nikon’s gold ring accent, but now it’s just a Canon market thing meaning “luxury.” Usually L lenses are costlier, heavier, better constructed, and have a larger aperture than their non-L counterparts. Due to advances such as USM and IS, the distinctive white body and red ring is now synonymous with “professional sport photography” in some circles. While there may be valid physics for the white body in astronomy, in photography the white lens is pure marketing, and brilliant I might add. [...]
February 28th, 2007 at 2:11 pm
Whatever it is. They are superior optics delivering exceptionally good image quality. The rest is history. The reason why smaller L series lens are black is becos they have a lesser surface area and therefore will head up less in the same heat compared to the amount of heat a Large black colored prime lens.