Repainting EF 70-200mm f/2.8L

[eugeniu_sofroni]

Has anyone repainted theirs ?

 

What precautions and what paints & techniques did you use ?

 

I want to take a used "storm trooper" (the white canon lenses) and turn it into

a "darth vader"

[dave_trayers]

Canon says there is a good reason the lens is white:<p>

<a href="http://photonotes.org/articles/beginner-faq/lenses.html#whitelens">Why are some Canon lenses painted white or silver?</a>

[franklin_polk]

Get a Lenscoat instead. You'll need to disassemble the lens if you want to do a good job of painting it, and it just isn't worth the time or effort. Here is the Lenscoat for the 70-200 Non IS (http://www.lenscoat.com/product_info.php?products_id=324); browse the site if you have the IS version.

[keith_lubow]

I am a fan of good-ol' gaffer tape myself. It is totally reversible, for one thing. It is also cheap and easy.

 

The white is to keep the lens cooler.

 

Keith

[jnicholson]

I think the white thing is just marketing more than anything else. I think the laws of thermodynamics make the whole "cooler" argument invalid.

[mars c]

"I think the white thing is just marketing more than anything else. I think the laws of thermodynamics make the whole "cooler" argument invalid."

 

Have you tried putting two lens, one white, one black under the sun for 30 minutes?

[keith_lubow]

Jamie,

 

Of which laws of thermodynamics do you speak? Explain how they invalidate the fact that a light coloring reflects more light than a dark coloring, before we are even into the realm of thermodynamics (HTFF). This, in turn, affects the thermodynamics of the situation, as heat is simply a "slower" version of light.

 

Keith

[neill_farmer2]

Hi,

Basic physics here. Light coloured bodies, because they reflect more energy in the form of light and heat stay cooler than dark objects which absorb energy. (that's why they're light and dark coloured!) Having a white lense to keep it a little cooler makes perfectly good sense.

I don't know if I'd put gaffer tape onto a beautuful L lense, I'd try for a tape that comes off a little more easily. The only time I ever used gaffer tape the paint came off with it when I removed it..

Neill Farmer

[William Michael]

>>> Has anyone repainted theirs ? <<<

 

No, and I would not.

 

I would use material (cotton and velcro), and make a cover in segments leaving the focus and zoom rings uncovered, if I had to.

 

>>> I think the laws of thermodynamics make the whole "cooler" argument invalid. <<<

 

Which law of thermodynamics?

 

(Perhaps it was a joke?)

 

From High school Physics I recall there are two, (from which other postulations are made).

 

In simple terms the first states energy is neither created nor destroyed, but is changed from one form to another.

 

And the second is the Law of Entropy, which is about each discrete energy exchanges being contained within itself: that is, within an exchange no energy enters or leaves that exchange.

 

It seems that both these laws, and taking into regard the reflectance and absorption of different coloured surfaces, indicates exactly the opposite of the sentence quoted.

 

And also what they, (mc, KL, NF) said.

 

WW

[ben_goren]

It's also worth noting that, while black absorbs heat much more readily than white, it also

radiates heat much better as well. That's the reason that NASA will put reflective materials

on the sunward-facing parts of their instruments, but paint the outward-facing parts

black.

 

In practice here on Earth, you're *much* better off putting all your effort into reflecting the

energy in the first place than you are by trying to radiate it away. You'd only be better off

with a black lens if you never took it out into the sun....

 

So, while there's certainly a marketing angle going on with the Big White Lenses, there's

solid science behind them, as well.

 

Cheers,

 

b&

[jwhite3.0]

Not to fuel the fire nor dispel physics nor re-hash old debates nor start new debates nor doubt the wisdom of Canon....

 

If color is important why aren't more camera bodies white or silver if reflecting heat is important? Afterall, the good stuff is in the camera and the same physics apply to the body as well as the lens!

 

My camera is cooled by liquid nitrogen and two heat sinks but I'd like to hear various reasons as to why the bodies aren't white. I'll piggyback Eugeniu's question rather than start a new thread.

[William Michael]

>>> It's also worth noting that [. . .] <<< (BG)

 

I was just about to respond... until I began reading your second paragraph.

 

:)

[PuppyDigs]

"I think the white thing is just marketing more than anything else. I think the laws of thermodynamics make the whole "cooler" argument invalid."

 

Jamie you obviously have never left your camera on a tripod all day while shooting surfers in the Hawaiian sun. As I recall my black Nikon teles were hot enough to fry eggs on. White is indeed much cooler. I also bought a white car! My prior car was black and, although it looked great, was so hot after a few hours in a Honolulu parking lot I could barely breathe when I climbed in. White makes a huge difference.

[dogbert]

If you don't use it for long periods in the sun then I don't see why you shouldn't paint it black. Clearly white makes sense for lens that is going to be stuck on a tripod for 10 hours in the blazing Australian summer sun at the cricket.

 

However, for a lens that is primarly going to be used for travel and the like such as a 70-200/4 L, black would be preferable.

[bluphoto]

Okay so now we have established the reason why "L" lenses are white - apparently.

 

Now I'd like to find out why non-L lenses are black and for that matter my 17-40L? - why not paint them all white - surely it would be (slightly) cheaper for Canon to have one paint process rather than two, although I accept that they probably have more than one "lens component spray booth". I'm sure Canon are piling hundreds of thousands into each lens development to perfect the noise of the motor, the design and manufacture of the elements, the smoothness of the focus mechanism, and then they throw black paint on it and cook the darned thing - by their admission.

 

Is white paint more expensive than black? - I'd like to see a car dealer agree with that one - they usually charge more for black cars - at least here in the UK.

 

I also agree with the fact that if Canon is worried about heat build up, then they should be consistent and paint all their pro bodies white as well - although I'm not sure I'd like the look of an Albino 1Ds3/4.

 

Does anyone know what was the "first" Canon white lens, and was it looked upon as a refreshing change by Canon, or a wierd anomaly?

 

White paint IMHO is more about exclusivity than science - although I agree that white paint reflects heat and so the lens is kept slightly cooler.

 

The funny thing is that many of the L lenses are indeed designed to be used in Low light situations - the very situations where the chance of heat build up is at its lowest.

 

Go figure!

[mars c]

"The funny thing is that many of the L lenses are indeed designed to be used in Low light situations - the very situations where the chance of heat build up is at its lowest."

 

If you're talking about white L lens,

 

The only white L lens that are most used in the dark are the 70-200mm 2.8 Lens, the rest are mostly used outdoors like the 100-400, 300mm, 400mm.

 

"White paint IMHO is more about exclusivity than science - although I agree that white paint reflects heat and so the lens is kept slightly cooler. "

 

Nikon also offers white colored lens, And also Sony and minolta, so what's exclusive in that, And to say that white lens are slightly cooler under the sun, I dont think so. White lens are much cooler than black lens under the sun on prolonged period of time.

 

The problems with heating up the lens are , The glass might warp or deform, the adhesives might weaken and the weather sealing might melt on intense heat.

[terry_smith2]

I wish Canon would sell touch up paint in little bottles for the "white" L lenses...

[lee_shively]

Cameras used to come in silver chrome as well as black. The chrome bodies were always cooler to touch than the black. I preferred the chrome bodies to the black ones when they were available.

 

I've used EOS bodies with a "white lens" on tripod in full summer sun and I know the lens remains relatively cool compared to the body. That's why I always carry white cotton handtowels in my camera bag--cover the camera body and it remains cool. A big rubber band will hold it on in the wind.

[DickArnold]

Spray painting the lens could be quite harmful to the functioning of the lens and require a lot of masking. Hand painting would look terrible. Neither paint would bond well to the original surface as it appears to be baked on. Do you want sand it down to improve the bond? I know on my motor home that spray painting cylindrical steel parts has to be redone quite often. How will painting your lens improve your pictures?

[walang_pangalan]

Thermodynamic argument (and observed reality for that matter) says that, for an object in thermal equilibrium with its surroundings, emissivity == absorptivity. This means that two objects in radiative contact with some reservoir (aka "the Sun"), they will both come to the <i>same temperature</i>, <b>regardless of their color or other properties</b>.

 

<p>The color will certainly change the equilibrium times, but not the final temperature. For a camera lens or other thin tubes, I would expect these equilibrium times to be rather short, to the point that color has no practical effect. The better argument is that Canon's "white" is just a marketing tactic, otherwise Nikon and everyone else -- who employ engineers of equal merit -- would be using white too.

 

<p>(And I guess it should be noted that things that take a long time to heat up will take a long time to cool down. Generally speaking, it's a good thing if your optics quickly equilibrate, so if any color is to be preferred, choose black.)

[jwhite3.0]

Walang, you seem to know a lot more physics than I do but to put a reality spin on the situation can you tell me the time scale by which two differently colored objects will reach the same temperature?

 

I don't disagree that equilibrium will take over but are we talking minutes, hours, or years?

 

In any case, isn't this all pointless? Most of cameras/lens will operate up to 130 F or something close to that. We are more likely to take our cameras into a local watering hole before they malfunction from heat.

[arie_vandervelden1]

I would paint the lens pink. Less chance of getting it stolen.

[keith_lubow]

Walang,

<P>

What you are talking about applies to energy transfer from surface to surface when both are in direct contact, not to attenuation of energy, which is what is affected by the tone of the paint. If the lens were being heated by the surrounding air, you would be correct.

<P>

If you want to get technical with your argument, consider the following: The lens is actually heating the air in contact with it in most cases; not the other way around. The flow of energy is from sun (a physical nuclear course) to a series of energy waves of diminishing frequency, finally resulting, upon impact with the lens, in enough attenuation to produce heat. It would follow that the more light energy that is reflected from the lens, the less light energy that gets slowed in to heat energy.

<P>

To confuse things even more, "heat" technically is: Energy transfer from one surface to another due solely to a difference in temperature.

<P>

I wish they would just make the whole lens out of glass.

<P>

Keith

[keith_lubow]

"(a physical nuclear course)" should have read: "(a physical nuclear source)".

 

Keith

[mark_chappell]

Sorry Walang, you're flat wrong here.<P>

 

To add to what Kieth said, emissivity must equal absorptivity <B>at the same

wavelength</b>. However, the wavelength spectrum of sunlight is vastly different (much

shorter)

that the wavelengths in long-wave 'thermal' infrared, which is what is radiated from a lens

at normal everyday temperatures -- i.e., a whole lot cooler than the Sun's surface. <P>

 

So it is quite true that a white object and a black object will reach different equilibrium

(i.e., final) temperatures if both are placed in sunlight (the black object will get hotter; how

much hotter depends on a lot of complex factors, size being one of the more important).

That's because the white object absorbs less sunlight and reflects more sunlight than the

black object. However, in terms of long-wave infrared, the chances are that black and

white objects have roughly equal emissivity.