# History behind the white lens



## lopicma (Jan 16, 2013)

Is there a thread relating to the history/reason for Canon using white for it's premium lenses?

I also notice that Sony has a couple of white lenses as well.


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## eml58 (Jan 16, 2013)

Dont know if there's a separate thread, but I'll throw in my understanding. I have read that Canon say they Paint the Large Lenses White as the Bodies are mostly metal, therefore subject to heat absorption, the Glass in most Canon Lenses (Not All) is fluorite crystal, which is sensitive to heat which can make the elements expand & contract, the white colour reduces the amount of expansion & contraction in the Metal body and the fluorite elements.

The fact that Large White Canon Lenses stand out in the crowd is I imagine a positive as well.

Nikon I believe offer some of their large Lenses with an optional white paint finish.


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## LDS (Jan 16, 2013)

AFAIK when there was only "black" lenses many photographers started to cover them with more or less improvised white covers to avoid excessive heating. Canon started to deliver some FD L telephotos in white finish, starting with the larger and more expensive ones - i.e. the FD 300/4 L was black, while the FD 300/2.8 L was white, the FD 400/4.5 was not even an L less although it used UD glasses... probably later Canon understood even cheaper lenses could benefit from the white paint (and the L "signature"), and maybe commercial reasons were important as well.


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## Juvenall (Jan 16, 2013)

From the source: http://cpn.canon-europe.com/content/education/infobank/lenses/black_or_white_lenses.do


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## icantpickaname13 (Jan 16, 2013)

It's meant to be a universal symbol for someone who has great taste in camera equipment so that others with inferior gear/taste might take note and up their game. 
Also on an unrelated note when shooting in the desert in summer my camera body is hot to the touch and my white glass is much much cooler...


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## Mt Spokane Photography (Jan 16, 2013)

Juvenall said:


> From the source: http://cpn.canon-europe.com/content/education/infobank/lenses/black_or_white_lenses.do


+1
This is the correct answer .


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## Hobby Shooter (Jan 17, 2013)

Mt Spokane Photography said:


> Juvenall said:
> 
> 
> > From the source: http://cpn.canon-europe.com/content/education/infobank/lenses/black_or_white_lenses.do
> ...


Hmm, so throwing in those lens covers in the equation will be a bad thing? I walk around with my 70-200 MkII and obviously people notice it, where I live it's not a good thing to be noticed for your expensive gear. I guess I'll just have to stay careful as I've done up until now.


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## bycostello (Jan 17, 2013)

as said.. to be reflective to limit expansion and contraction


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## Nishi Drew (Jan 17, 2013)

Some of Sony, a.k.a. Minolta's telephotos are white for a similar reason I think, they had white finishes since the early 90s as I recall, but could have started soon after Canon brought out their whites.

The main reason for white is to reflect the heat, but traditional lens designs didn't have so much of an issue with that, it was when Canon began using Fluorite elements in lenses like the mentioned FD 300 F/2.8 L that it became rather necessary, as Fluorite reacted badly to heat. Probably a lot worse then the average glass or metal bodies would in even the worst heat and weather. Eventually it did indeed become a symbol for the 'best of the best' telephotos, and lately with lenses like the 70-300 they're painted white just to show off it's "L status" when there's no practical reason to be sporting the white finish... just stands out unnecessarily for when it's compactness should help with maneuverability and stealth.


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## Jesse (Jan 17, 2013)

White doesn't absorb heat. The end.


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## unfocused (Jan 17, 2013)

Mt Spokane Photography said:


> Juvenall said:
> 
> 
> > From the source: http://cpn.canon-europe.com/content/education/infobank/lenses/black_or_white_lenses.do
> ...



I don't know, I kind of want to call b.s. on some of the official explanation. 

I'm sure that the _original_ purpose was as stated, but I'm also pretty sure that Canon uses white on lenses like the 70-300 "L" , 70-200 f4, and probably even the 300 f4 and 400 f5.6, as a marketing tool so us mere mortals can own a "white" lens.

After all, why would the non "L" versions of the 70-300 zooms be okay in black but the "L" version require white, when they all use the same aperture and why is the 200 f2.8 prime black while the 70-200 f4 is white?

Canon is a smart company. They know their white lenses are a good marketing tool and, regardless of the original reason, it's clear they are now using it for marketing purposes as well.


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## neuroanatomist (Jan 17, 2013)

unfocused said:


> ...why is the 200 f2.8 prime black while the 70-200 f4 is white?



Not denying that some of this is marketing, but in the specific case above, the 70-200/4 has a fluorite element, while the 200/2.8 does not (fluorite is more thermally sensitive than glass). But then...the 70-300L has no fluorite, nor do the 300/4 IS or 400/5.6 (although the 100-400 does), which is why I'm not denying some of this is marketing...


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## kubelik (Jan 17, 2013)

dilbert said:


> The interesting thing about white vs black is that if a white and black lens are both at the same temperature after being in the sun for some period of time then the black lens will return to a room temperature quicker than the light coloured one if they are both then taken into an air conditioned building.



has this been tested? I assumed the black vs. white thing only helps regarding heat absorption from radiation, but once you bring it into a room it should be cooling via conduction in the air, which shouldn't have anything to do with its color.


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## unfocused (Jan 17, 2013)

neuroanatomist said:


> unfocused said:
> 
> 
> > ...why is the 200 f2.8 prime black while the 70-200 f4 is white?
> ...



As usual, you know the technical specs far better than I ever will. But you also get my point. If I'm paying $1,300 for a lens, I want it in white and with a red ring, dammit!


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## kubelik (Jan 17, 2013)

dilbert said:


> kubelik said:
> 
> 
> > dilbert said:
> ...



interesting, so radiation is more important than conduction in cooling. thanks for the link!


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## Zen (Jan 17, 2013)

I don't know the answer re the testing of the theory on lenses, but I DO know from experience, that the white top on my race car, a '63 Morris Mini Cooper in SCCA "C Sedan" class, which was a metallic dark blue elsewhere, kept the interior much cooler than was the case in the cars that had darker colored tops. So, based on my experience, the lens story is entirely believable. ;D

Zen


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## LDS (Jan 17, 2013)

dilbert said:


> http://littleshop.physics.colostate.edu/activities/atmos1/ColorAndCooling.pdf[/url]



I believe you got it wrong - reread this passage:

"But *silvery metals don’t work like this*. They reflect visible light and they reflect infrared too. They don’t absorb it—and, more importantly, they don’t emit it! So, in this experiment, the two cylinders will cool at different rates. The *bare aluminum cylinder radiates less * and cools rapidly; the white cylinder (*and the color doesn’t matter—it could be any color at all!) * will radiate more and so it will cool off more quickly."

As long as you paint the lens metal, black or white - it will cool in a different way than unpainted metal. It's the paint that radiates. But the black lens will absorb much more energy - heat - than the white one... and a polished bare metal lens would be a nightmare


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## kubelik (Jan 17, 2013)

LDS, I read and re-read that paragraph, but I think that they're missing the word "less" in between "cools" and "rapidly". it should read:

"the bare aluminum cylinder radiates less and cools LESS rapidly; the white cylinder will radiate more and so it will cool off more quickly."

the statement about the color not mattering seems to be relative to an unpainted metal surface, not relative to other colors. compared to anything painted, reflective material will heat and cool more slowly. but between different colored materials, their relative level of emission will matter in comparison.


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## neuroanatomist (Jan 18, 2013)

LDS said:


> dilbert said:
> 
> 
> > http://littleshop.physics.colostate.edu/activities/atmos1/ColorAndCooling.pdf[/url]
> ...


Nope, dilbert is correct about the cooling rates, although the statement about silver vs. any other color in the link he posted may be a bit misleading. While it's true that painted metal will cool faster than the unpainted metal, metal painted black will cool faster than metal painted white. But, dilbert also makes an incorrect assumption, which renders his conclusion invalid:



dilbert said:


> The interesting thing about white vs black is that *if a white and black lens are both at the same temperature after being in the sun for some period of time* then the black lens will return to a room temperature quicker than the light coloured one if they are both then taken into an air conditioned building.


A black lens and a white lens in the sun for the same long period of time will NOT be the same temperature - the white lens will be cooler. In the sun, the temperature of each lens will rise until the heat gain from absorption reaches equilibrium with heat loss due to emission and conduction/convection. That equilibrium will occur at a lower temperature for the white lens (as much as 30-40% lower), due to lower heat gain because of the reflectivity of the white paint. So, when both lenses are taken into that air conditioned building, although the black lens will cool at a slightly faster _rate_, the white lens has less heat to lose, and thus will reach room temperature sooner.


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