Why white?

Does anyone know when - and more importantly why - Canon decided to make some of their L series lenses in the now famous off white colour? And why only in the longer focal lengths?

And why don't they make white bodies

Roy Mathers wrote in post #3454348
Does anyone know when - and more importantly why - Canon decided to make some of their L series lenses in the now famous off white colour? And why only in the longer focal lengths?

Part to show the rest of the watching world that you have a fancy Canon lens, part to reduce the absorption of heat.

[QUOTE=glitch;3454394]​...you have a fancy Canon lens...quote]

More like, you have lots of money

[QUOTE=SoaringUSAEagle​;3454470]

glitch wrote in post #3454394
...you have a fancy Canon lens...quote]

More like, you have lots of money

You had a lot of money

Apparently white disperses heat more effectively than black - although you hardly see Nikon lenses melting on the sidelines during the Olympics......so whilst that may in part be true, i think its also a cunning marketing ploy!

...I'll go with the "cunning marketing ploy" as well

Black lenses don't heat up like black lenses and therefore cuts down on optical distortions caused by heat around the lens. Take a Canon 100-400 around at the same time as a Bigma, and see which you want to hand-hold, and how the pictures come out from when the lenses were first used compared to after they have been in the sun for quite some time.

I can speak from experience about the touch issue after sitting in a Colts training camp in 95 deg weather during August with no shade, yeech. Not sure if this is the reason Canon used for the color, but I would rather handle a white lens during a 3 hour shoot in the sun than a black one, so I appreciate it.

Living in a place with lots of sun , I am not so cynical about Canon using white for the longer lenses. I bought a Silver 400D instead of a black one for that reason.
Mythbusters did a good experiment - 2 identical cars (apart from colour) parked in the sun. The black car got hotter faster and remained hotter through the day by a significant margin compared to the white car.

I'm sure it's in the canon EF book, that the lenses are white to reduce heat absorption

The L color is obviously a blatant mac ripoff.

But why only in the longer focal lengths?

I have heard that the white coating is used in lenses that incorporate fluorite elements, which are more prone to being affected by uneven thermal expansion. This would explain the bias to longer focal lengths.

That said, I have not personally checked all the lenses in the lens museum to verify that, but it seems plausible. Gimlet-eyed physics may be the core reason, but I'm sure the marketing side effect is also welcome.

vv
J.O.

Canon actually advertises the heat expansion properties. Read a magazine once in a while and you'll see the ad.

I did a quick search around the 'net and found some optics and physics references that indicate that not only does fluorite have a markedly different thermal expansion coefficient compared to glass, its refractive index is also strongly temperature dependent.

Two good reasons to take precautions to manage the temperature at least a little in lenses with fluorite elements. Plus it looks cool.

vv
J.O.