White Lenses and metal bodies

[hjoseph7]

I know allot of people wonder why Canon invented white lenses, I mean they make you stick out like a sore thumb. Many

people including myslef scoffed at the idea that white lenses reflect heat. Well the other day I was in the hot sun with my

little black all metal(that oneof the reasons I bought it "all metal") Point-and-shoot, when the camera started getting

Hot ,real hot. Not hot enoguh where you could fry an egg on it, but hot enough where you start worrying about your flash

card and other components inside the camera. I quickly took the camera off from around my neck and stuck in my pants

pocket to protect it from the heat. Score one for Canon.

[bryan_lardizabal]

See a former post on the topic -- http://www.photo.net/canon-eos-digital-camera-forum/004o05

[arie_vandervelden1]

"hot enough to fry and egg ... I quickly stuck the camera in my pants pocket." Man, reading that makes me pucker up...

 

I was gonna make a joke about putting a big white lens in the pocket but I won't. I'm probably out of line already. Moderators please feel free to remove

[JDMvW]

See also http://www.photo.net/classic-cameras-forum/00Pr8i among many others.

[PuppyDigs]

"Many people including myslef scoffed at the idea that white lenses reflect heat."

 

Hmm, you didn't pay attention in basic science courses in secondary schools! Dark colors absorb infrared radiation while

light colors reflect it. Wear a black T-shirt and walk around in the sun and you'll quickly feel the difference from a white one.

Here in Honolulu white cars are the most common color because everybody knows they stay much cooler while exposed to

our blazing tropical sun. If you shoot surfing and leave your great white tele on a tripod for a few hours the camera body is

burning up while the lens is still cool. I leave a small white towel on my camera to help protect it.

[steve torelli]

I never really appreciated the big whites either until I moved back to Memphis from up Nawth. It makes a great difference, especially if you live in a warm, sunny climate.

[john_h.1]

they make you stick out like a sore thumb.

 

Why?

[PuppyDigs]

I used to shoot with a black Sigma 400 5.6 APO and a EF 300 4L USM. Reactions from bystanders were basically the

same. No diff from black to white. However methinks some photogs are more self-conscious when donning white glass,

Personally I don't give a damn anymore.

[bobatkins]

Minolta made a white version of one of their maxxum bodies (7?). That never seemed to catch on though. I don't recall any white Canon bodies ever being produced (or at least not for sale).

[danielransom]

I think the silver bodies are the next best step toward white. I think white is probably right all round, lens and body. But I just couldn't shoot w/a white body. Funny what makes a difference.

[JDMvW]

And note also that the white makes for excellent camouflage for winter use.

 

Note for example, in the unauthorized photo below of the new Canon 25000mm f/3.5 L T (T for tracked) how the lens blends in nicely with the snow in Honshu, where the shot was made by an industrial spy from Nikon.<div></div>

[derrickdehaan]

I do know this.....that white paint sure is expensive!

 

 

Derrick

[HenryUK]

The colour of a paint in the visible spectrum has no relationship to its propensity to absorb infra red radiation.

 

Generally speaking white, red, blue, green and black paint all absorb the same amount of infra red.

 

Canon's use of a light shade of paint on their expensive lenses is all about marketing and not about temperature rise in direct sunlight.

 

Henry

[frank_ernens]

Henry, you need to step out of chilly Britain, because if you lived in a hot country you would appreciate the white lenses.

White cars are measurably cooler than black ones when left in the sun (Mythbusters showed it if you don't believe me), but

no Australian needs to be told that. A black lens is absorbing the light, which is why it is black, and the energy from the

absorbed light has to go somewhere, be that as heat, electricity or whatever.

[JDMvW]

I can't help but note that the other side of the issue is that a "black body" not only absorbs radiation more, but it also radiates more. Many years ago in South Dakota we rigged a field shower for a Smithsonian field party. We put a barrel on top to hold the water and painted it black, so the water would warm up during the day. Well, that summer was unusually cloudy and cool so the water ended up colder instead of hotter than the water out of the hose. Of course in those days we had only all-male crews, so maybe it was just as well. ;)

[alan_myers]

Canon painting their lenses white has an important purpose besides either user comfort or marketing gimmick, and they weren't the first or last to do it.

 

It has to do with using fluorite elements in their big tele lenses. Fluorite is sensitive to heat, expanding and contracting much more than most other types of glass, and messing up the lens' optical formula in the process. So the white paint was originally used to reduce heat absorption. Other manufacturers have done the exact same thing with fluorite lenses. Catadioptric or "mirror" lenses are another type where some have been painted white to reduce heat absorption in an effort to prevent optical problems.

 

I'm sure that the marketing folks at Canon noticed how it made their lenses stand out along the sidelines at the Super Bowl and every other major sports event. So there are now some Canon lenses that don't have fluorite elements but are also painted white, probably more "for show" than for any practical reasons.

 

Most other manufacturers currently do not use fluorite elements. They use other less heat-sensitive types of glass to accomplish similar effects. But, in the end, they simply don't have to worry about heat absorption as much, so can paint their lenses black or any other color they wish.

[kelly_flanigan1]

Canon didn invent the white lens; they copied many other past lenses; of other makers. They copied Nikons super white-grey 1000mm mirror lens of the early 1960's. This "copied" the white Exakta mirror lens of the 1950's; the 1000mm F5.6 Jena Catioptric; which had a built in filter turret. These white designs were copied from the many white amateur mirror reflecting telescopes made in the 1900's and on. This was copied from cave man who learned that white clothing was cooler dark clothing when working in the got sun. Its pure bunk that Canon invented the white lens. With a mirror/cat type lens or telescope heat is a real problem; making barrels/tubes white was common knowledge in amateur telescope books of the 1930's. Its abit shocking that its not widely known that most white objects are cooler that most black objects that are in direct sunlight. Even frogs and lizards know this.:)

[sbp]

In theory, Henry is correct. In practice, I'm not so sure. Last weekend, we had lunch at an outdoor cafe. I set a 5D with 70-200

f2.8 mounted on the empty chair next to me. In the time it took us to eat, the body became very hot, while the lens remained cool.

Marketing ploy or not, I'm convinced that the lighter color does make a difference.

[frank_ernens]

Two paints (white and black) may well have the same infrared absorption characteristics, but it hardly matters, as most of

the energy in sunlight is in the visible and UV parts of the spectrum (higher frequency, therefore higher energy).

 

I was reminded watching a documentary that went out last night in Australia that the effect has a name: the albedo effect.

The Arctic sea ice absorbs 25% of the sun's energy (it's white), and the ocean absorbs 93% (it's dark blue), hence the

concern aboiut it melting.