Why is the 50 'lux SILVER heavier than the BLACK?

[jackperk]

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I'm speaking of the newest model, the ASPH version of this wonderful lens. I know that the silver version is heavier than the black and would like to understand why.

 

PS - I just received my SILVER version and admire the images greatly.

 

jack

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[redbaron]

Most silver chrome lenses are made of brass, black ones of aluminium.

[RoySmith]

Most silver chrome lenses are made of brass, black ones of aluminium.

 

Would the brass lens wear slower (last longer) than the aluminum one ? What are the advantages of one over the other - other than the weight difference?

Ciao,

Roy

[Jager]

I don't think there is any meaningful evidence that brass (chrome) lenses wear better than their aluminum (black) counterparts. Much as those of us who prefer chrome lenses - and would like to justify their extra weight - might wish otherwise.

 

There are many anecdotal stories that the chrome 35 Lux ASPH has fewer focus shift issues than the black version, but I'd be reluctant to ascribe to that anything other than happenstance.

 

I'm certainly in the camp that vastly prefers chrome lenses and, given the chance, will always buy it over the black paint version - but I'd be the first to admit that that is purely an aesthetic preference and has nothing to do with function or durability. I do think there is a different feel to chrome lenses, but it is very subtle.

[250swb]

I'm speaking of the newest model, the ASPH version of this wonderful lens. I know that the silver version is heavier than the black and would like to understand why.

 

PS - I just received my SILVER version and admire the images greatly.

 

jack

 

The reason it is made from brass is so it can be plated, its purely a practical thing to do with the chrome plating process.

 

Steve

[alcyst]

The Leica pdf "Technical Data"-sheet gives the weight as 335g, no alternative for the chrome version. They do specify the 24mm f2.8 chrome as 98g (34%) heavier. I prefer the lighter version.

[frc]

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Confusion as always. Brass or aluminum are the materials the lenses are made of from which one can choose. Alu. light weight. Brass heavier weight ( for those who want more substance ). Silver chrome finish only on the brass lenses. Black chrome on the aluminum lenses.

The more shiny black paint on both, this is more of a luxury item for those who prefer looking at paint wearing of in such or such a way. ( the desired brassing only on the brass ones though )

I could not care less about a lens being silver or black as long as it is made of brass, and if a certain lens isn't available in brass I'll buy it in aluminum.

 

And for some myth building: my 35 Lux asph has no focus shift. Brass one of course;-).

[adan]

Further clarification - even "aluminum" lenses have some brass inside - and "silver" lenses still have some aluminum elements as well as brass.

 

You can see the threaded brass focus cam peeking out at the very bottom, in the curved notch in the lens mount, in these images of the 75 and 35 Summicrons and 24 Elmarit:

 

http://photovillage.com/images/T/75_2_asph.jpg

http://en.leica-camera.com/assets/gallery/1604.jpg

http://us.leica-camera.com/assets/gallery/1602.jpg

 

This cutaway shows what is brass (yellow) and what is some other metal (silver) in a (black) 28-35-50 TriElmar:

 

http://2.bp.blogspot.com/_QomDizboK-A/SF15sX_hCXI/AAAAAAAAAbI/Z71BW3MFt_A/s400/47.jpg

[SteveYork]

Confusion as always. Brass or aluminum are the materials the lenses are made of from which one can choose. Alu. light weight. Brass heavier weight ( for those who want more substance ). Silver chrome finish only on the brass lenses. Black chrome on the aluminum lenses.

The more shiny black paint on both, this is more of a luxury item for those who prefer looking at paint wearing of in such or such a way. ( the desired brassing only on the brass ones though )

I could not care less about a lens being silver or black as long as it is made of brass, and if a certain lens isn't available in brass I'll buy it in aluminum.

 

And for some myth building: my 35 Lux asph has no focus shift. Brass one of course;-).

 

Weren't the black paint lenses made from brass?

[Jamie Roberts]

{snipped}

And for some myth building: my 35 Lux asph has no focus shift. Brass one of course;-).

 

Mine too

[underground]

I have a black 90 Cron pre asph. and it is very heavy. does that weight come from

the amount of glass, brass, or both?

[adan]

All the post 1980 90 Summicrons (APO or otherwise, M or R) have a pretty hefty third element, and the pre-APO's have a thick 2nd element as well. But the heavier the glass, the heavier the surrounding metal has to be to remain stiff and prevent binding. So probably both.

[lars_bergquist]

Adan is right of course. The internal parts of the lens mounts are always made from the materials that function best in their specific places. Focusing helicals e.g. are made with brass sliding against aluminium. Other parts vary. Some are actually steel -- the aperture mechanism. You will NEVER encounter a lens mount made solely from brass, or solely from aluminium. Not one made in the last hundred years.

 

With hitherto existing surface treating technologies, aluminum did not take a satisfactory satin chrome finish. So, in order to offer chrome-finish lenses, those outer parts that took this finish had to be made out of brass. Hence the weight difference of on the average about 100 grams between black anodized and silver chrome lenses.

 

But the internals are not different. May I also remind you of a third internal component -- glass? And that it is the glass, not the metal, that makes the image. Focus shift ("backfocusing") or 'Blendendifferenz' in German is caused by residual spherical aberration. Stopping down cuts off the peripheral rays, which come to a slightly different focus than the central rays. So the optimal position of the 'combined' focus shifts slightly to the rear. (This phenomenon is common to all fast lenses; the difference is the degree to which th designers found it desirable to correct for it). With identical optical construction, identical focus shift occurs. An external focusing ring e.g. made out of brass won't change that. Conclusion: The supposed immunity of "brass lenses" to backfocusing is urban legend. Or superstition, in order to call a spade a spade. You might just as well try anointing the lens with bat grease.

 

The operative difference is not in the individual lenses, but in the individual users: Some are more nervous about fine points of lens performance than others. What you can discern on a test bench is one thing; in actual picture taking, NO focusing method -- scale, rangefinder, reflex or any AF system existing -- will ensure absolutely perfect focusing in all instances. Focusing just has to keep within acceptable limits. Leica RF does. It is just that with the change to digital, limits have shrunk a bit. But the M rangefinder does still deliver. Whenever I have got a misfocused picture with my 35mm Summilux ASPH, the error has been mine. But yes, I am waiting for the v.2.

 

Finally, allow me to repeat: Sharpness is not the only factor that makes the picture. Few of the iconic images of the twentieth century were extremely sharp. Content trumps technique. Sharpness is the fetish of boring photographers.

 

The old man from the Age of S-l-o-w Lenses

[yanidel]

I had been looking for an understandable definition of focus shift, that is perfect. So this means all 35 Lux Asph have it but those that do not see it might have their lens front-focusing a bit so it compensates. In my case I intentionally misaligned my rangefinder so it slightly front focuses at F1.4 but decreases a bit focus shift impact when stopping down.

[peter_n]

Weren't the black paint lenses made from brass?

Yes.

Sharpness is the fetish of boring photographers.

Lars this is a quote to place beside HCB's "bourgeois concept"!

[lars_bergquist]

I had been looking for an understandable definition of focus shift, that is perfect. So this means all 35 Lux Asph have it but those that do not see it might have their lens front-focusing a bit so it compensates. In my case I intentionally misaligned my rangefinder so it slightly front focuses at F1.4 but decreases a bit focus shift impact when stopping down.

Yes, it is inherent in the design -- in the speed of the lens, in fact. The phenomenon has been known for ages, but most lenses were so slow that they did not show much shift. In actual prectice, tolerances also work out so that all lenses are not hundred percent identical -- just 99.9% in Leica's case.

 

As with all lens aberrations and problems, you cannot remove them all completely, because the design decisions necessary to get completely rid of one may increase two others! All lens designs are of necessity compromises. While we used film exclusively, a certain amount of focus shift could be tolerated because of the depth of the emulsion (and because there was no instant chimping down to pixel level). With the no-depth digital sensor, the amount tolerable is less. This became the bane of the Summilux-M 1:1.4/35mm ASPH, which straddles the two eras. The lens is perfectly useable in practice, but the shift can be detected, and this makes some of us nervous, and some hypochondriacs go bananas.

 

So the next version of the lens will have less spherical, and hence less focus shift. It may take two aspherical surfaces, or a floating element, or whatever, because a deterioration in the rest of the lens's performance will not be accepted.

 

Meanwhile, Leica seem to have become less interested in supplying silver chrome lenses. Working with two different mount varieties does of course complicate production. And again, outside finish does not influence optical performance.

 

The old man from the Age of Fast Photographers and Slow Lenses

[SJP]

.... and some hypochondriacs go bananas.......