Black vs silver lenses in direct sun.

[qruyk12]

I know a lot of DSLR lenses are grey or white to offset the effect of heat expanding the lens cases (perhaps changing tolerances). Anyone have any info on this, for the different colour Leica lenses in direct constant sunlight? So much talk about back and front focus problems has me wondering.

 

[StanSmith]

Comparing the Heat Transfer Coefficients of brass and aluminum, which represent silver and black lenses respectively, we can see aluminum insulates heat while brass conducts heat. So theoretically this means the core of the lens will reach ambient temperature faster with silver lenses. So if you go from a hot sunny sidewalk into a cold air conditioned taxi your silver lenses will get cold faster. This may be relevant if you live in a hot humid environment and walking out of a dry cool office, hotel room or taxi with a silver lens may not be good for your lenses due to moisture build up. I always get this with Leica lenses but never with plastic Nikkors. Probably because plastic insulates heat very well.

 

[Jerrold]

My experience with my silver M8 & 25 ZM in bright sunlight was that they are very reflective, slightly blinding almost!

There is a degree of logic to the lighter colours reflecting light radiation better, but when I was in the Gobi a while back with my white nikon lens, it still got quite warm to the touch.
The flip side is that a black object would radiate built up heat better than a white object and cool faster...

However in that sun and heat I was more concerned about me melting before my camera!

 

[mwooten]

The M8 safari kit lens is silver. I'm sure that's not for cosmetic reasons. 🙂

--michael

 

[sevo]

Comparing the Heat Transfer Coefficients of brass and aluminum, which represent silver and black lenses respectively, we can see aluminum insulates heat while brass conducts heat.

Not at all - aluminium has almost twice the heat transfer coefficient of brass, and is indeed the best heat conductor relative to mass. Its heat storage by volume however is lower thanks to its low mass.

Besides, black or silver is a design decision - chrome and nickel plated brass lenses are frequent, and so are black anodized aluminium ones.

Personally I would estimate the difference to be fairly pointless. We aren't talking about high reflectivity insulated thermal protection covers, but of lumps of metal. If you point your exposure meter at either, you'll see that the reflectivity of each is fairly modest, and very far off the 99.xx% of a protective gold foil, and within a 2-3EV range of each other. Throw in that black surfaces are better radiators, and that either absorb the majority of incoming radiation, and the difference becomes very modest - a black alu lens may heat up to equilibrium in five minutes where a chromed brass lens takes ten, but the end temperature will be pretty exactly the same, and the black alu lens will cool down faster. In either case, if there is a risk of the equipment overheating to critical temperatures, you must protect them against direct sunlight.

Sevo

 

[Sparrow]

I have a bag for my cameras 🙄

 

[Tom A]

I dont think it matters in "every day" use- even in a hot climate. However if you leave the lens in direct sunlight for an extended time - you can start "degassing" lubricant and end up with 'fog" on the elements. A black lens will absorb heat faster - but also shed it faster so it cools down better.
Of course, if you allow a camera to heat up sufficiently - it may affect electronics and also the film. I have seen film literally attached to the film gate of a M when the owner had left it lens down on a table in the sun.
Some of the early AF lenses with built in focussing motors were prone to problems in hot/cold weather. At the winter olympics in Calgary - some of the shooters stationed at the slalom/downhill had lenses seize when they stood for hours in blazing sun - but also cold wind. The sunny side expanded and the shadow side contracted. I suspect that Canon went to their white/off white coloring to stop this - and it was a brilliant marketing strategy - everybody "in the know" can spot the Canon mega-teles in a scrum these days.

 

[MRohlfing]

... if you leave the lens in direct sunlight for an extended time ...

... you will get that famous Leica glow! 😀

 

[Pablito]

I dont think it matters in "every day" use- even in a hot climate. .

I respectfully, VERY respectfully disagree somewhat, Tom. It depends how you define every day use. I do a lot of work in very hot and sunny climates. Sometimes you just cannot get out of the sun. I have a light colored bag and the cameras inside stay MUCH cooler than in a back bag (when in direct sun). Likewise, black cameras and lenses do get much hotter than silver/chrome ones. You just need to be aware of this. It's really scary how hot black equipment can get in direct sun.

 

[Tom A]

There are always exceptions to the rule. If your job forces you spend hours under a blazing sun - yes i would use chrome cameras and lenses too. I was more thinking along the lines of moderate use in that kind of climate. It is also possible to shade cameras under jackets and or in bags.
I have travelled and worked in VERY hot climates (Central Sahara, Israel, Australia's outback etc) and black cameras get hot - but cool quickly if shaded.
Today I think the biggest problem is with electronics. They are a bit more sensitive to heat (and extreme cold) than purely mechanical cameras, though I have always avoided taking anything like that into extreme climates or conditions.
Usually what happens is that in hot climates, combined with humidity, dust etc - ANYTHING will act up with time. Maintenance is paramount.
My other problem is that. at least Leica's chrome lenses are heavy and heat can sap energy and they suddenly become much heavier. A couple of M's, 3-4 lenses will have you "wilting" quickly, unless you are used to the conditions.

 

[kbg32]

I wouldn't worry about it. I only have black cameras, and have spent three months in Morocco during the summer with no problems at all. I don't let my cameras sit in the sun when not being used. Use common sense and you, they, will be fine.

 

[payasam]

Not such a bright idea, "direct constant sunlight", never mind lens colour.