Elmar 50/2.8 - dismantling

[RichC]

I've got a 1950s Elmar 50/2.8 that needs a bit of a clean: does anyone know how to remove the front element?

I'd like to send the element to Arax for recoating, but I understand that he only accepts elements, not complete lenses.

I did ask a month or two back, but had no replies. Also searched the Web, to no avail. Surely someone must've had this 50-year-old lens apart!

TIA

 

[Kim Coxon]

Hi Rich,
Not certain about the Elmar. The collapsible Cron had/has a lock ring around the nameplate which unscrews and is fairly obvious. The summars had a very different arrangement. Details here. http://www.angelfire.com/biz/Leica/summar.html
If it is like this, Arax won't deal with it.

Kim

 

[Ian L]

Hello,

I have a 1950s M-fit 50/2.8 Elmar (I think it's a later one as it has a combined feet/metres scale) which had dust under the first element. It took me a while to figure out how to remove it. The trick is that there are *two* rings on the front that need to come off. The first one is a plastic "friction" one, so you need to press down on it quite hard and turn it to remove. I used a small circle of foam (cut from the bottom of an old mouse mat), made sure it was clean and placed that over the ring and front element for protection. Then I used a plastic bottle cap the same diameter as the ring, pressed down hard and turned. Mine needed a bit of effort, but it did come off okay.

The second ring is a metal one that's actually holding the front element in place. It has a couple of notches opposite each other for screwing in and out. I think you're supposed to use a special "double-pointed" screwdriver to get these things out (which I don't have). I ended up strapping a couple of micro screwdrivers together, and the combined width of their handles luckily meant the two points were the correct distance apart to fit into the two notches. Then I *very carefully* applied pressure until the ring came loose. This is obviously a bit of a dodgy stage as a slip could easily lead to a gouged front element...

Once the second ring was off, I gently upended the lens onto a clean lens cloth, so the front element could fall out. If I remember, it's quite a thick bit of glass. There may have been a thin metal ring (a spacer?) under it as well -- it's a while since I did this! But, anyway, with the front element out I was able to clean off the dust and reassemble it quite easily.

I don't know if all these lenses are constructed the same, but that's how mine worked anyway. Hope this information helps, and if you do have a go, be careful!

Cheers,

Ian

 

[Ian L]

Now I think about it, the first ring (the plastic friction one), if I remember correctly, holds the name-ring in place - you take the name-ring off after the first ring.

Cheers,

Ian

 

[RichC]

Thanks Ian - that all makes sense: I could loosen the slotted ring but after a few turns it would butt up against the first ring, so obviously something had to come off first - just what I couldn't fathom!

I'll have a go when I get home from work.

Cheers!

 

[RichC]

Need a bit more help I'm afraid...

My lens is similar Ian's, but isn't as straightforward: after removing the two retaining rings as described, there's a third.

Under this third lens is a thin black washer that sits on the front lens element, then the element itself. Unfortunately, it seems that this third ring has to be removed.

This third ring is locked with a small retaining screw in between the edge of the ring and the metal lens body, preventing the ring from turning. I've removed this screw but cannot undo the retaining ring: it has a smooth surface, so I can't use a pin spanner, and I've tried all sorts of things to try and grip this ring and turn it (e.g. a rubber bung) - but it won't budge.

Has anyone any suggestions? (Apart from get someone else to do it - which would cost more than the lens is worth.)

 

[RichC]

Bump...

Anyone any suggestions on how to remove that stuck ring?

TIA

 

[Kim Coxon]

Hi Rich,
I haven't taken an Elmar apart so I am guessing to a certain extent. Are you sure there is another ring and not a detent or similar? On the collapsible Crom and Tele elmarit, there is the black ring you describe but this is a spacer/cushion for the element, I suspect to prevent damage the the element by over tightening. The black "ring" on this is a straight push fit and it is a devil to take out. It is almost impossible to get something in on the outside of the ring. You need a lot of care and a sharpened "soft" object to get under it, lever it up slightly and then get a finge nailm underneath to flick it out. I wouldn't recommend this for a straight clean job but as you are going to get the element repoished, try something like a flattened matchstick to get under it.

If you want to speak on the phone, send me a pm and I will give you my phone number.

Kim

Bump...

Anyone any suggestions on how to remove that stuck ring?

TIA

 

[RichC]

Thanks Kim.

I think you're right that this stuck ring is an inteference fit and not threaded, and would explain the presence of the lock screw.

I'm at work now, but will examine the lens more closely when I get home.

 

[RichC]

Given up! 🙁

That ring just won't budge...

 

[former member]

Responding for the Lens Hacking EXTREME! Thread.

I cleaned a 50mm f3.5 Canon Serenar, an Elmar copy, with such a ring in it. I believe that this tube is "baffling" (for real) designed to eliminate reflections.

I can't state the two are the same. After removing the retaining screw, the tube came out by shoving a rubber cork into it and then turning the tube until it came out.

 

[RichC]

After removing the retaining screw, the tube came out by shoving a rubber cork into it and then turning the tube until it came out.

Thanks Brian - I'll have another go, but I'm not sure that it'll budge (tried turning a rubber bung with all my strength but the ring didn't move).

 

[former member]

When I need more force, I used a pair of retaining ring expansion pliers. Gets more force on the rings. Squeezing the pliers makes them go outward, against the side of the ring.

The construction on the Canon lens may be diferent from the Leitz lens. BUT on the Summicron Type I Rigid, things were just a very tight squeeze. The elements required using pliers to pull on the suction cup to get them out. Required severa tugs, with cleaning fluid on the cup to get it to hold tighter.

 

[kinoglass]

Once the plastic thin washer removed the first element should came loose. Some times it is a little tight because the famous Leica tolerances (!) A little heating around the elements with a hair drier will loosen it and it should come out on its own weithg or just with a little tapping of the lens on a solft clean cloth.

This element is far too small for most optical shops to handle it, they can't strip the damaged coating prior to recoating. Leica sells the elements brand new, here in the USA for US$180. The elements under the diaphragm blades is often a little haze from oil deposits, but it is also soft coated and very easy to damage when cleaning.

The 50/2.8 Elmar uses (or used to) rare earth elements, I think the replacemnt element is enviroment friendly, old ones "rare earth element" lanthanum is what it is and that is why theses lenses age "phoney" Optically I like them.

 

[RichC]

This element is far too small for most optical shops to handle it, they can't strip the damaged coating prior to recoating.

Arax in Ukraine said they can handle it - so long as I send them just the element and not the complete lens.

I'll try a bit of gentle heat next weekend when I get a bit of time.

Thanks for your help, Brian and kinoglass.