Howto dissasemble a Elmar-M 50mm/2.8 ?

[sergio_sousa]

<p>Greetings!</p>

<p>I have a foggy front element and would like to try to clean it. Didnt find much information on the web and was wondering if anyone on P.net has done this, and what would be the best aproach. <br>

I have tried to dig through the front, took the retaining rings and the little thin shim that is located imediatly behind the front element, but after that I dont know now how to remove it (should the glass come out or is there a metal structure that holds the glass tight in there?</p>

<p>Should I try to access it from the back?</p>

<p>Thanks in advance for any help, it will be very helpfull...</p>

<p>Sergio Sousa</p>

[ronald_moravec1]

<p>Do not touch the soft coating inside. They are soft as a baby`s behind and require pro work. I believe they do a chemical clean.</p>

<p>DAG camera repair or Sherry at Golden touch. You stand a 90% chance of screwing it up.</p>

[canfred]

<p>Ronald is is spot on in addition to his comment decentering could occur rendering the lens useless.<br>

People like Sherry or DAG have equipment to collimate.</p>

 

[peter_a__nyc_]

<p>DAG replaced the front element of my old screw mount Elmar 50mm 2.8 because he said the fog could not be removed. He said the fog is due to the type of glass they used.</p>

[sergio_sousa]

<p>Hi there!<br>

The kind of haze I have is only around the outside of the front lens, and is very very hazzy. From what I have read on the web, It should be rests from the aperture blades oil. <br /> I know the internal coatings are very thin and will come out if I try to clean it, but paying $250 to repair a $150 lens seems a bit silly to someone on a tight budget like me. Besides, I am a wide angle guy and would really think seriously on doing this if It were a 35mm... (It came with my "new" M2... I really cant live without one!)<br /> <br /> Looks like I have two alternatives:<br /> <br /> - Use this lens like it is and stop it down to 5.6 (at 5.6 aperture blades block the hazy part of the front element) or use it wide open for strange effect and "old look" portraits; <br /> <br /> - Sell it like it is, but I am not sure of how much would it sell, in this condition... (anyone knows/is interested?)<br /> <br /> What would you do?<br /> <br /> Regards and thanks for the tips...<br /> <br /> Sergio</p>

[Brian1664876441]

<p>You write that the haze is on the outside front of the lens.</p>

<p>Do you mean that it is on the outer rim of the inner surface, that you can only get to by removing the element?</p>

<p>I've not taken a 5cm F2.8 Elmar apart, but have disassembled a 9cm F4 collapsible Elmar, 5cm F2 Rigid Summicron, and several collapsible Summicrons. On each of these, the front element is in tight and does not "just drop out" once the retaining ring and shims are gone. I used a soft rubber suction cup to get them out. You have to be VERY careful. I used one made for a "window decoration" (Barbie sun-catcher) to remove them.</p>

[sergio_sousa]

<p>Hmmm... that could be the tool I need... since it is made of rubber it shoudnt make bad things to the outside glass... I will try to find one :)</p>

<p>Thanks</p>

<p>Sergio</p>

[sergio_sousa]

<p>Brian:</p>

<p>thanks for the great tip... using a rubber suction cup (has to cup to the right size) I was able to remove the front element with no problems... :)<br>

That is the good news... now for the bad news:<br>

- After cleaning, the marks are still there... this kind of haze problem has to do with the aperture blades oil, does it make permanent damage to the lens surface?</p>

<p>Regards,</p>

<p>Sergio</p>

[Brian1664876441]

<p>I have had aperture oil etch the glass of some lenses, in particular the Canon RF's.<br>

On the Leica lenses, it gets into the coating and stains it. I bought one coated summitar that was like that. Ammonia based eyeglass cleaner removed "part" of the coating, like the damaged portion of it. Great results with the lens. I just converted a 1939 Sonnar "T" that had coating damage to the surface behind the aperture. It was hazed over. The same cleaner took the damaged coating off, leaving clean glass behind. Good results with the lens.<br>

The worst I ever had was an opaque collapsible Summicron. I polished the coating off myself, using polishing sheets made for fiber optic connectors. A lot od work, but it improved the lens. Soft, but usable.</p>

[sergio_sousa]

<p>Brian, thanks once again for the response and good tips... This lense had (and partly still has) this strange very dense haze, but only on a outside ring of the front element. Let's say that from 5.6 to 16 the lens are clear. I cleaned the inside with lens cleaner fluid and it got a big better, but the "haze" is still very present. I wonder if is not glass damage... Do you think I should try to clean it even better?<br>

Sergio</p>