Leica LTM Xenon 50/1,5: inside and out

[tobias]

Hello,
as a sideline to a thread i posted about a IIIa and Xenon 50/1,5 which i picked up a couple of weeks ago (see here), I plea for an inside hand.

My intention was to clean the glass of the Xenon, and now i am having some problems with the aperture blades. It was not my intention to take the aperture apart in the first place, but i also did not expect the same retaining screws to connect two rings.

it tightens up too much when i screw the front group in, which is frustrating, and it makes me assume that i have something sitting wrong, as it moved freely before i took the lens apart. also, for some reason, the blades seem to have to be pulled and pushed, and i can see them flexing, when i operate them, which again is not good.

i thought this was the solution: to lay them out, and follow the order of the wear patterns on the bottoms of the blades, then insert them into the housing in the order from left to right. but it is still not happy.

yup, cleaned them with zippo fluid, so they should be clean as can be.

Has anyone taken one of these apart, or do any of you have any clue as to what might be nagging me this time?

many thanks,
T+

 

[dougdarter]

The problem may be that you are tightening the set screws too much when you reassemble theaperture/lens module.

These screws are intended to be screwed in, but not tightened. You may have found that the effort to unscrew them was disproportionate, but this will have been due to the fact that they have not been moved for 70 or so years, and the tiny amounts of oil in the threads has hardened.

Don't forget as well, that you have removed the lube from the blades. They may be clean, but they will still need a microscopic film of oil - the fricton between the unlubricated blades may cause them to bind so that they are not meshing correctly.

Lube and re-assemble, but just replace the set screws without overtightening. Don't overtighten either when you screw the body elements together again.


I hope that this does the trick.

 

[DrLeoB]

Also be sure that whatever lube you choose, it has low, or no volatiles and limited creep. Fluorocarbon lubes are best.

Another thing I have used in the past is to dilute the lubricant into an appropriate solvent about 1:100 dilution. This makes applying a thin film easy. I use Krytox, a fluorocarbon lubricant from the hard disk industry, diluted into a zero residue fluorocarbon cleaner (carburetor cleaner.)

Residue free means that if you allow the solvent to evaporate on clean, shiny aluminum foil, there is nothing visible left. The foil needs to be rinsed thoroughly before doing the experiment, because there is always a thin oil film an Al foil to keep it shiny in thebox.

If you are suspicious of any lubricant, you can place a small amount of it on you clean foil and place it on a coffee cup warmer for an hour or two. If there are volatiles, you will see a progressive development of halos as they evaporate.

Good luck.

 

[LeicaTom]

I really hope you get it back together again......I want to see some shots with a Xenon, take some photos and share with us sometime, ok? - ohh is this lens coated or uncoated?
(some were sent back to the factory after the war to be coated)

I`m STILL looking for a coated one someday...but I`m not fussy I`ll take an uncoated one too 🙂

Tom

 

[tobias]

Hello,
I finally got the lens together yesterday, but have not had a chance to test it yet. maybe today.

As far as i can see, the lens has a very faint coating. the early coatings seem hard to see, but the front element has very light cleaning marks that change the surface in the middle of the lens, similarly to the way i have an Elmar 50/3,5 and a Tessar which have never given me any problems for this.

as for the lube on the blades, i really was under the impression they were meant to be dry, though such lubricants would, most certainly, not hurt. I may look into whether i can get hold of them. my ordering of the blades by sight was correct, though they fit better 6-> 1, and having rotated a couple of holes, with a magnet. only at this stage did the external ring fit in one direction.

if anyone needs help with one of these, i made drawings somewhat like Rick Oleson's, for posterity.

if there were an easy way to put an LTM on Nikon F mount, i would have instant digital and sacreligious test shots.

salut,
t

 

[DrLeoB]

Good job Tobias.

When I referred to lube'ing the blades,I really meant where the shafts pivot in the internal retaining frames of the blades. The blades themselves are definitely supposed to be dry as you correctly surmised.

 

[John Shriver]

The early Leica soft coatings have a reasonably visible, if not vigorous, color. By definition, your Xenon was coated when manufactured, then it would be a Summarit.

My Hektor 135/4.5 (600XXX) has a pale violet-blue coating. My Summitar 50/2 (589XXX) has some blue reflections, some gold. Both lenses are very early coated specimens.

On the other hand, it is quite possible to more or less entirely clean these soft coatings off, as has happened to my "bad" Elmar 90/4. So perhaps it was coated later by the factory as an upgrade, and then ineptly cleaned off by someone.

Glass can get a natural surface oxidation (?) that serves as a lens coating. That's how they got the idea.

 

[tobias]

First test images: soft prints, soft (diffused tungsten) light, t-max 400 (the only stock i had in fridge) developed in t-max. the vignietting seems to be something that is currently inherent to my enlarger, which i have not yet figured out.

3 images, in descending order:

Elmar 90/4 (1955), Summar 50/4 (1937), Xenon 50/1.5 (1938),

i felt it was necessary to compare, with one lens being one i knew was modern and optically perfect (the Elmar).



t

 

[LeicaTom]

First test images: soft prints, soft (diffused tungsten) light, t-max 400 (the only stock i had in fridge) developed in t-max. the vignietting seems to be something that is currently inherent to my enlarger, which i have not yet figured out.

3 images, in descending order:

Elmar 90/4 (1955), Summar 50/4 (1937), Xenon 50/1.5 (1938),

i felt it was necessary to compare, with one lens being one i knew was modern and optically perfect (the Elmar).



t

Good to see another Leicaphile who photograph`s pretty gals, I see Italy`s beauties are no exception - great images Tobias!
(they have a 1960`s art magazine feel to them - the vignietting adds a real retro touch to them)

I really like the effects of the Summar and the Xenon, it`s been forever I`ve waited to see someone else other than myself use a female model for black and white lens tests, with old lenses very nice....very Euro!

Tom

PS: I`ve always wanted a Xenon.....post #491xxx lens in a factory coated version, someday...someday

 

[tobias]

Thanks Tom,
had i been clever i would have shot a couple of frames of an oblique grid to check collimation, but i did not. silly me. next roll.

but how better to test a lens, than on that which they should be used. soft on soft. you would not use a soft lens on architecture, it would not make sense. and besides, i really wanted to make an early Hepburn feel, and a lot of early actor's folio shots were done on 8x10, and good god and wow, but the 1.5 seems to have a deapth of field which is almost as good. maybe more like a 4x5, but super shallow. look at the difference between the who arms, which cannot be more than 12cm apart.

I am pleased with the lens, so far.

t

 

[LeicaTom]

Thanks Tom,
had i been clever i would have shot a couple of frames of an oblique grid to check collimation, but i did not. silly me. next roll.

but how better to test a lens, than on that which they should be used. soft on soft. you would not use a soft lens on architecture, it would not make sense. and besides, i really wanted to make an early Hepburn feel, and a lot of early actor's folio shots were done on 8x10, and good god and wow, but the 1.5 seems to have a deapth of field which is almost as good. maybe more like a 4x5, but super shallow. look at the difference between the who arms, which cannot be more than 12cm apart.

I am pleased with the lens, so far.

t

Yes, a "clear" glass late production Summar`s the next Leitz LTM lens I want,
*around #491xxx+ (1939)* - especially for soft Retro portrait shots in Blk N Wht
to reproduce 1930`s and 40`s artistic looks

Yes the Xenon`s very shallow wide open and the results look really good, Summarit`s will give the same results as well - very very similar, it`s the same formula as the Xenon, just coated

It`s going to take some time to find one (a Xenon) I`ve seen some lately but too steep at $500+ that`s too expensive, you were lucky with yours and the price you paid, if you ever see anymore hanging out over there give me a yell!

Tom

 

[Pherdinand]

Lovely.
..........

 

[noci]

ahhhh, I'm also looking for that lens... or a good summitar 1,5. but those seem hard to come by in Europe, without lens fogging, that is.

 

[tobias]

I shall have to take more pictures with the Xenon, it seems.

I must admit that i have never had such a bright lens, and had, generally, overlooked the purpose of such brightness. but it was rather odd to have the Elmar and the Xenon sitting there, both full open, but the equivalent exposure to be 1/60" and 1/1000". That, i must say, is quite a difference to use, as well.

but the deapth of field is amazing, as i find it very hard to work with my half-self-built 5x7" camera, when i am shooting people. it is a different beast. i like the buttery ease of the RF, which is, ultimately, why we are all here.

t

 

[LeicaTom]

I shall have to take more pictures with the Xenon, it seems.

I must admit that i have never had such a bright lens, and had, generally, overlooked the purpose of such brightness. but it was rather odd to have the Elmar and the Xenon sitting there, both full open, but the equivalent exposure to be 1/60" and 1/1000". That, i must say, is quite a difference to use, as well.

but the deapth of field is amazing, as i find it very hard to work with my half-self-built 5x7" camera, when i am shooting people. it is a different beast. i like the buttery ease of the RF, which is, ultimately, why we are all here.

t

Yeah, I like the buttery ease too.....not just at breakfast 🙂 ummmmmm Xenon! 😉

Tom

 

[noci]

where did you find the xenon anyways, tobias?

 

[tobias]

Arezzo, Italy.

There is a huge antique market on the first weekend of each month, i.e. this weekend. some cameras appear mixed in with clothes and furniture and watches and stuff, but rarely anything too spectacular. The guy who i bought the IIIa and Xenon from deals in german items, predominantly from the period between the wars. he also had a russian 1936 olympic edition leica copy, in nice condition, and a pair of binoculars, but nothing else with lenses.

t

 

[noci]

a great find, indeed. was also just thinking about flea markets as a (possible) sourcing opportunity..

 

[sanmich]

Hi Tobias

I had an almost similar story.
I have limited experience in DYI's in cameras. mainly III's dismantle to a certain degree and some focus relube on two canons.

I tried to clean a very early Xenon I have, but man, this lens is complicated!
I finaly decided that I hadn't the skills and sent it to DAG. The CLA was one of the more expensive I had on a lens, and Don told me that he regarded all these lenses as some kind of "prototypes": extremely complicated to dissemble/reassemble.

So thumbs up for you Tobias to enough a man to this kind of DYI !!

 

[Vince Lupo]

I have to say that the Xenon lens is one of the best LTM 50's I've owned. Frank Marshman at Camera Wiz gave mine the full spit and polish a while back, and he commented to me after having worked on it that 'it's a really nice lens', which, coming from Frank, means a lot to me. I finally got to use it on a trip to Europe these last few weeks, and the results were fantastic, even at wider apertures. So Tobias, I hope you get lots of good use out of your Xenon as it is a fantastic piece of glass!