Weight of chrome and black lenses

[stric]

I'm curious... why are Leica chrome lenses heavier than black ones?

Are they made of different materials or is it simply the paint, i.e.

chrome?

[kelly_flanigan1]

With a 50mm F2 Summicron; the chrome lens is made out of brass, the black version is made out of aluminum; which weighs less. Brass has a higher density than aluminum. In Zorki; a black or chrome looking Jupiter-8 5cm F2 LTM are both vary light; made out of aluminum. The "chrome" looking Jupiter-8 is not really chrome; just finished aluminum.

[ronald_moravec1]

Chrome is plated on brass. Black is some type of finish on aluminum which is lighter than brass.

 

Very old black lenses were a black "japan" finish on brass.

[kelly_flanigan1]

In the slide rule days we mechancial engineers would often use 0.1 as the density of aluminum; and 0.3 for brass. This is in pounds per cubic inch. There are a many different families of aluminums and brasses, so to get a 3 place number one should use the Metals Handbook; and know what alloy you are dealing with. The old Shigley text for college students uses 0.098 as a swag for aluminums; and 0.309 for brass. There are a mess of brass types; one can get in trouble if one foolishly assumes these numbers are gospel for all brasses and aluminums.

[eliot_rosen1]

"Very old black lenses were a black "japan" finish on brass."

 

? I thought they were black painted on brass. Is there something Japanese about the paint that was used? :-)

[kelly_flanigan1]

In optical engineering a first pass back of the envelope slide rule type calc would use the density of aluminum and glass to be the same; about 1/10 lb per cubic inch. Rare earth glasses weigh more.

[Rob F.]

Both the chrome and the black lenses employ both brass and aluminum in their construction. These two metals are used because when they slide against each other, they have a natural non-binding action, almost like having their own lubrication.

 

The difference is that the chrome lenses use brass for the larger, outer component, and the inner unit is made from aircraft aluminum. The outer unit has to brass so it can be chrome-plated. The black lenses are anodized, rather than plated, so aluminum is the metal of choice. That makes the black ones lighter, for reasons Kelly explained.

 

Got any Calphalon cookware? It's got a hard anodized surface over aluminum. That's what I think the Leica "Black Chrome" amounts to. It's Calphalon, fer cryin' out loud! And it looks like Calphalon does when it wears, too!

[kelly_flanigan1]

Japan paint is a type of paint. Canadian Balsam is a type of balsam. English Peas are a type of pea.

[kelly_flanigan1]

With the Nikkor LTM lenses, both parts of the helix are brass with my 8.5cm F2 . I wouldnt assume that all chrome Leica lenses are a aluminum brass mix. The new LTM 11619 Summicron 50mm F2 I have here is really heavy. I would bet it is almost all brass, and not a mixture. I am sure not taking it apart to settle a dissagreement!

[eliot_rosen1]

"Japan paint is a type of paint. Canadian Balsam is a type of balsam. English Peas are a type of pea."

 

No kidding? I wasn't aware that Japan paint was used on older Leitz lenses.

[mike-images]

Peter A has it - just like silver chrome needs the brass to stick to so does the BP. All BP lenses are heavier than equivalent BC lenses....ahhhh trivia.

 

M

[dave_s]

Japan black: (Chem.) a quickly drying black lacquer or varnish, consisting essentially of asphaltum dissolved in naphtha or turpentine, and used for coating ironwork; - called also Brunswick black, Japan lacquer, or simply Japan.

 

Ain't Google grand?

[eliot_rosen1]

"Ain't Google grand?"

 

Yes it is. But the issue is whether Japan black paint was used on early Leitz black paint lenses. Did you find any information on that? I couldn't.

[jati_lindsay]

i bought a chrome 35 'lux instead, when i had originally planned to get a black one, and let me tell you, its HEAVY. almost twice as heavy as a black one. its built like a tank. if you turn the aperature ring on a black one, then do it on a silver one, youll see what i mean. it definitely feels like the lens will never malfunction in your lifetime. which is why i bought it. the downside though, is that it makes your M so heavy that you really dont want to walk around all day with the camera around your neck anymore. as great as the lens is, and as much as i paid for it, im really thinking about getting a smaller 35 as an everyday in the street lens.

[piotr_panne]

I\'m wondering why they\'d use aircraft aluminum anyhow. It seems that beer can aluminum, given how thin it is, would be much stronger.

[icuneko]

Beer can aluminum is for the photographer, not the camera. "burp..."

[david_werbeloff1]

Eliot, in my experience as a harpsichord maker I use Japan colors to decorate the instruments. They are supplied as a super-saturated suspension of the ground color pigment in a solvent. This differs from regular paint in the concentration of solid pigment which is available for depositing on the painted surface and results in much better coverage.