Collapsible Summicron - how to open up

[marzipan]

Hello,
Does anyone know where to find a service manual or a description of how to unscrew the different parts of a Collapsible Summicron? Want to clean some haze and dust without damaging anything. Yes, I have read all the warnings about the soft coatings... Will be verycareful. I do have tools and experience with similar repairs.

Regards, Martin

 

[ferider]

In all likely-hood, the haze is just before and after the aperture.

For the two copies I cleaned, the front part of the optical barrel just unscrewed (grab the ring in front of the aperture). Then you can access and clean the above two surfaces. Don't apply too much pressure.

Roland.

 

[johnamazement]

As far as the front of the lens goes, once you've undone the front retaining ring you will need to take out the front elements with a rubber suction cup as they're held in pretty tight by friction.

Regarding the rear, I would strongly advise NOT trying to dismantle the focussing section as you need a proper tool to grip and undo it correctly; it is not a simple matter of undoing screws as in the L39 collapsible lenses. If you try and get in by undoing the little screw in the barrel revealed when the lens is collapsed you'll be in all sorts of trouble (don't ask me how I know). Once you've removed it, the barrel is very hard to re-insert: the ball bearings that guide it are held in by springs and will pop out when it is removed, also the felt which protects it is a very tight fit.

I did a full strip down and clean of a Summar and a Canon 50mm 1.8. Both were very straightforward and successful, transforming pretty tatty lenses into very good performers. Emboldened by this I had a go at the collapsible Summicron and wished I hadn't. It was a far tougher proposition altogether.

It maybe that you're infinitely more skilled in these matters than I am. Nevertheless, you have been warned!

 

[marzipan]

Thanks for the advice! Some more questions: When unscrewing the front block, holding the knurled ring, what is the safest place to grab and hold against? The collapsing tube perhaps? Secondly, I often use naphtha for optical surfaces. Is this "Leica-safe" if I dont apply pressure with the cotton ball?
I wish there was some repair manual to find, makes a lot of difference to see drawings of the parts. After a long search I found the one for my Nikon F cameras, and it really helped.

 

[ferider]

Thanks for the advice! Some more questions: When unscrewing the front block, holding the knurled ring, what is the safest place to grab and hold against? The collapsing tube perhaps? Secondly, I often use naphtha for optical surfaces. Is this "Leica-safe" if I dont apply pressure with the cotton ball?
I wish there was some repair manual to find, makes a lot of difference to see drawings of the parts. After a long search I found the one for my Nikon F cameras, and it really helped.

Naphtha and cotton balls are fine.

I extended the lens and held it by the focus mount (the lens rotation turned counter clockwise will stop, if extended), if I remember right.

Don't apply too much force - if it doesn't work, stop. If I remember right from Brian Sweeney, some newer collapsibles have a locking screw.

Roland.

 

[marzipan]

Unscrewed the front block from the lens body. Was easy, kitchen gloves give an amazing grip. Did not know that the aperture "dot" is on a separate ring between the knurled front and the aperture ring, interesting, I guess one could drop it if not careful.

Found that the slight haze is only behind the front element, not on the surfaces around the aperture. Good! Closed it up again for the time being. So now I need to find a clean suction cup. And a circular friction tool for the name ring.
There are spanner slots outside this name ring, is this a separate ring that keeps the elements in?

 

[Harry Lime]

Do you have an optical bench and collimator, so you can assemble it properly?

It's a really nice lens and not cheap. Spend the $100 bucks and send it to someone who has the proper tools to do the job correctly.

 

[marzipan]

I do not have collimator, but it would be useful and interesting to have one. I wonder though, how many have one even of the real camera repair workshops.
I know, I know, too many enthusiasts are tinkering and sometimes destroying precise equipment (or unknowingly making it out of spec) - that is why I initially asked if a repair manual was available. Dont want to remove the wrong screw... :bang:

 

[marzipan]

So... does anybody have a link to either photographs or a drawing of how the different rings and optics are connected in the collapsible?

I have so far found the very useful description of the Summitar on Justin Lows site, but it seems the 1st Summicron has many details that differ. There is also a really good repair training manual on the M2 which includes the DR, but nothing on the Collapsible. (http://www.pentax-manuals.com/repairs.htm)

I would love to eventually send the lens for recoating at CRR Luton, but they had a loong waiting list last time I asked.

Martin

 

[stuart_115]

Thank you for the instructions in this thread. Today I saw fungus in my lens and got worried that it would etch my coating. I opened up the lens and could clean the affected elements 🙂.



I'll have to do it again though, as I didn't have the time to clean it properly with a soft cloth / cotton. But at least now the fungus is out.