check out - http://www.klt.co.jp/Nikon/New_Products/index.html - and scroll down to look what they've done with four of their lenses. Nikon must be getting tired of all the white lenses on the sidelines of sporting events.

-- Richard Tope (RTope@yahoo.com), September 05, 2000

Answers

The above was obtained from the EOS list at eGroups.com.

Dick

-- Richard Tope (RTope@yahoo.com), September 05, 2000.

Camouflage in snow indeed! Does Nikon know nothing?
There is a very good technical reason for having light coloured barrels on long lenses, and that's to reflect heat away, and minimise thermal expansion. This keeps 'focus creep' to a minimum, and helps to keep all the glass elements in proper relationship to each other. If Nikon don't realise this, they oughtn't be in the business. They're certainly not the firm whose system I bought into over 20 years ago.

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 05, 2000.

Now we all know who is copying who!!! Still can't believe that there's no "VR" in their big glasses and no "S" in their 80-400 lens.

-- nguyen thang (nguyentnt@hotmail.com), September 05, 2000.

NEWS FLASH! you're 31 years late.

Follow this link to see Nikon's first white lens: http://www.cameraquest.c om/100063f.htm.

-- Geoffrey S. Kane (grendel@pgh.nauticom.net), September 07, 2000.

NEWS FLASH!

I can't count! ;-)

It's supposed to be 41 years.

-- Geoffrey S. Kane (grendel@pgh.nauticom.net), September 07, 2000.

"There is a very good technical reason for having light coloured barrels on long lenses, and that's to reflect heat away, and minimise thermal expansion. This keeps 'focus creep' to a minimum, and helps to keep all the glass elements in proper relationship to each other. If Nikon don't realise this, they oughtn't be in the business"

Does anyone have any evidence that white color have any appreciable effect on element position? Or is this simply one of those pseudo- scientific explanations concocted by the marketing department and propagated by non-critical devotees?

-- Chuck Fan (chaohui@msn.com), September 07, 2000.

Of course it has an effect. Basic physics tells us that black things absorb more heat radiation than white things.
Touch a white car and a black car that have been parked in the sun for the same length of time.

As for the f/5.6 Zeiss lens being 'decades' behind Nikon. Think again. A few years maybe. I can show you many references to the 1000mm f/5.6 Zeiss (Jena) lens from the mid 1960s.

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 08, 2000.

Pete, my link was not a "Nikon is better than Zeiss" taunt, but rather a comment that white Nikkor lenses have been around for a few decades.

FWIW, white (well really they're "gray") AF-S Nikkor became a Japan-only special order item sometime last year. I guess they proved popular enough to become an "international" product.

-- Geoffrey S. Kane (grendel@pgh.nauticom.net), September 08, 2000.

It wasn't taken as a taunt Geoff.
I really have no special loyalties to Nikon or Zeiss Jena, they're both legendary optical companies in decline. :^) I was just refuting the assertion by whowever wrote the article on the 1000mm mirror Nikkor, that it was decades before Zeiss came out with a faster lens.

In the meantime I've looked up the expansion co-efficient of Duralumin. A 500mm long lens barrel will expand by more than 0.17 mm for a change in temperature between 25 and 40 degrees Celsius. (pretty typical for a black-painted object sitting in the sun, I think) This is a factor of 20 more than the precision that most lenses are designed to. Or put another way, a focus shift of 7 metres in 100!

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 08, 2000.

Here in the Midwest, I've long been aware of how alarmingly hot my black Canon cameras (and any black lenses) can become when for example, I'm engaged in railroad photography and am waiting for a freight train to come along, with my camera tripod-mounted on hot, sunny days. In fact, I keep a white piece of rainfly material with me to cover my camera in these circumstances. Canon's decision to paint many of their telephoto lenses in an off-white color makes perfect sense, and indeed when using my "white" EOS lenses, they are merely warm to the touch under the above described conditions, while the black gear may be almost too hot to touch for more than a moment or two! I believe this heat issue can potentially cause or invite real problems, especially for expensive lenses. For example, the adhesive cements that hold certain elements in precise position may soften, or other components may shift or buckle due to the stresses of thermal expansion upon heating, and contraction upon cooling. No doubt there are other potential dangers to extreme heating of lenses.

I've periodically heard complaints from (for example) some nature photographers who feel that Canon's big white lenses shout "I'm here!" to wildlife. These individuals may resort to covering these lenses with camo tape, or even spray painting them. A less invasive but equally effective solution is to buy or make an elastic camo "sock" to fit over the lens when needed. Although I've not yet made one myself, my plan would be to buy some elastic medical/orthopedic-type tubular sock material from a drugstore or medical supply house, and then simply dye it in a camo pattern, to be fitted over the lens when needed.

-- kurt heintzelman (heintzelman.1@osu.edu), September 08, 2000.

Pete: I realize that white objects do absorbe radiative heat less readily then black objects, and therefore tends to acheive lower themal equalibrium temperatures. I do believe a white lens would be cooler to the touch under a hot sun than a black one. That could be an important advantage under many situations. But that is far different from saying that black lenses are appreciably more effected optically by the hot sun than white ones. Some say higher temperature of black lens throws elements out of position. I have never seen any evidence of detectable optical degradation due to normal thermal expansion. Some people have claimed that higher temperature causes debonding of elements or failure of internal structures. Yet I've never heard of a case where a lens, white or black, failed due to normal solar heating.

If there is any evidence that white lenses fare appreciably better under the hot sun than a white one, I like to see it.

-- Chuck Fan (chaohui@msn.com), September 09, 2000.

The point is Chuck, that it's only a coat of paint. Costs no more, (probably less in fact) for white paint than black. If it keeps the lens cooler, then that can only help. Black paint, on the other hand, if it has any effect at all, will only cause harm. (Unless you're on night manoeuvres with the SAS!)

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 11, 2000.

Maybe the manufacturers need to consider polished aluminum barrels.

-- Jeff Hallett (franjeff@alltel.net), September 12, 2000.

"Costs no more, (probably less in fact) for white paint than black. If it keeps the lens cooler, then that can only help. Black paint, on the other hand, if it has any effect at all, will only cause harm. (Unless you're on night manoeuvres with the SAS!) "

The issue isn't based on whether white paint ought to help based on glib rationalization. It should be based on whether it can actually be shown to help in reality.

-- Chuck Fan (chaohui@msn.com), September 12, 2000.

Perhaps one of you fine gents or ladies can perform a real live experiment! MTF tests of a quality optic at the same target, f-stops, controlled lighting etc., with the only difference being the temperature of the lens barrel (perhaps via the use of a radiant heater)? It wouldn't matter whether the lens was "L" white or standard black, as the idea is to see if the heat energy truly has any discernable impact on optical performance -- not which lens is actually better under heat situations.

This proposition is to satisfy all of the above posts insisting on hard data (in fact, I'm surprised it hasn't been done already).

It is a well known fact that metal expands & shrinks under thermal variation. Since most of the optics are hard mounted in the lens barrel (except for the floating focus elements/zoom elements), and optical performance design is all about where to put what shaped lens where to achieve the desired effect, I find it hard to believe that there would be no impact on optical performance due to expansion & shrinkage. Of course, the qualitative differences may only matter to MTF freaks. :-)

In any case, both Canon & Nikon have many fine professional optics in their stables, regardless of barrel color.

-- Hung James Wasson (HJWasson@aol.com), September 02, 2001.

I have seen a couple tests involving various branded lenses at I believe 200 or 300mm and one was white and the other black. I don't remember the link or whether I read it in print and I hope someone can find it. Anyway, the study showed that yes, the white did in fact help minimize shifting of the elements. It varied on the particular lens if its painted black because of individual build quality and resistance, however the white lenses still displayed signifigantly less shift and the test images were sharper. I guess its hard to say all black lenses will react the same, but painting it white is an intelligent precautionary measure. None the less, the black lenses shifted enough to produce visible changes in sharpness and had varied amounts of shift, I guess depending on the build quality and how secure lens elements were in that particular piece. Its safe to say that two of the same model 300 2.8s experience different amounts of shift if they're painted black, but experience signifigantly (and a worthwhild difference) less if white.

-- Carl Smith (emorphien@mail.rit.edu), December 03, 2001.