how easy is it to clean the inside of the rear element of a leica summicron 35 f/2? is this something i can attempt myself? is there easy access to this portion of the lens? thanks for any info!

-- tristan tom (tristan@tristantom.com), June 07, 2001

Answers

Sorry to barge in but I have a 90/4 screwmount with a slight amount of haze somewhere within the elements. Is this also something I can attempt myself.

-- Gerald Widen (gerald@sfa1.com), June 07, 2001.

. . . . reminding me of my own 90 Elmar experience 25+ years ago. I though it was a bit cloudy, so I started taking it apart. Imagine my dismay when the diaphram blades all fell out in a pile and I couldn't figure out how to get them back. Of course now I know what those tiny screws on the aperture ring do, and why to leave them alone. . .

In short, every part of a camera and lens is accessible, if you know what you're doing. If you don't then you risk flying springs, lost click-stop ball bearings, etc.

Now I'll shut up and sit back and wait for someone who knows about 35mm Summicrons.

-- Michael Darnton (mdarnton@hotmail.com), June 07, 2001.

in my case, i see some small specs on the rear element when looking through the lens from the front and shining a light through it. i think i may be some evaporated oil from inside the lens. when i got the lens (used from keh), there was a bit of oil on the aperature blades. i made no real notice of it at the time but perhaps this excess oil has now gotten on the inside rear element glass.

it's not a big deal, i was just curious if it was easy for me to access the element myself to clean it off. if it isn't i won't worry about it.

after all, fog, haze, and dust probably won't affect your pictures unless it's so bad that you look at the lens and immediately go 'yuck, what's all that milk doing in there!'

-- Tristan (tristan@tristantom.com), June 07, 2001.

My humble opinion and advice: Let an expert do it! I can strongly recommend this gentleman. He can repolish and recoat your Leica lenses and turn them into works of art!

The Focal Point- John Van Stelten 1017 South Boulder Road Suite E-1 Louisville, CO 80027-0027 Tel.- 303-665-6640 Fax - 303-665-3803 focalpt@ecentral.com

-- Muhammad Chishty (applemac97@aol.com), June 07, 2001.

"after all, fog, haze, and dust probably won't affect your pictures unless it's so bad that you look at the lens and immediately go 'yuck, what's all that milk doing in there!'" This is unfortunately not the case Tristan. I had even a slight fog in a few of my lenses, and the difference in the image quality after they were cleaned was significant. Much better contrast in particualr, and a much greater resistance to lens flare of all types. Dust and tiny bubbles in the glass will have nearly zero effect, but any kind of a haze that can be seen when shining a flashlight through the lens is showing up in your pictures already. Taking lenses apart without the propper tools and little or no experience usually results in a poor outcome. Its one thing if its the lens off an old $50 TLR, but a whole other thing to me to take apart an expensive Leica lens. There are so many things that can go wrong, I don't even have time to list them all.

-- Andrew Schank (aschank@flash.net), June 07, 2001.

What Muhammad said.

I had dust on the inside of one of my lenses -- I thought it would be easy to get at, and I have good tools and a pretty good mechanical knowlege. The result? ...Now you all know why I had to make my "repair facility" post yesterday. Yes, that is a big "S" stamped on my forehead...

-- Jack Flesher (jbflesher@msn.com), June 07, 2001.

I wouldn't try to disassemble the 35mm lens. I did that to mine, and it did not go back together properly. Had to let Leica do it for me. I got the impression that the groups of elements do not move together as a solid unit when the lens is focused, unlike the other lenses, which unmount from the barrel quite easily. This all happened some years ago, and the details are a bit hazy today. I do remember being without the lens for some time, however.

-- Keith Nichols (knichols@iopener.net), June 07, 2001.

I had a coversation with Sheery Krauter about this recently, and she told me she gets have taken apart equipment and a bags full of parts sent to her on a fairly consistant basis. One fellow, who was a surgeon, couldn't believe that someone with his level of intelligence couldn't take apart a lens, clean it, and put it back together again. How hard could it be, right? Of course, he totally screwed the thing up. Sherry got a kick out of the arrogance of the fellow, and basically thought to herself, why would she have gone through extensive training and internship if it was as easy as it looks?

-- Andrew Schank (aschank@flash.net), June 07, 2001.

Dont attempt to dismatle any Leica lens. Yes, you can unscrew Leica lenses, but you will never be able to put it back, to the extreme accuracy required for the spacing of the elements--- that is the distance between one lens and another, a few degrees of turn of screw may to to much or too few, and destroy the painstaking care Leica did in lens assembly, every lens element when put on must be tested for center using laser centering equipment, and the lens spacing must be kept within extreme tight tolerance.

YOu may be able to remove a speck, but your Leica lens is completely ruined.

Leave lens cleaning and reassembling to Leica trained technician !

-- martin tai (martin.tai@capcanada.com), June 07, 2001.

In many cases a front or rear element or group can be removed by simply unthreading it or removing a retaining ring. In such a case it would be quite difficult to disturb the lens' collimation. (Getting at the internal elements is another story!) But in all cases the risk is slipping and gouging the glass, dropping it, or separating a cemented pair. Some lenses have coatings on the inner surfaces which can be very easily scratched. Finally, it is a daunting task to get the element back on before some specks of dust settle back inside. Tristan--what do you do for a living? I say, spend the time doing that, pay the camera repairman to clean the lens.

-- Jay (infinitydt@aol.com), June 07, 2001.

To give you an idea what kind of precision is required for Leica lens, I use Summilux 35mm/1.4 as example.

The first air space thickness of Summilux 35/1.4 is 0.273 mm; the thickenss of second airspace is 6.825 mm.

Now, how are your going to get this kind of precision with bare hands ?

There are always people want to "fix" their Leica lenses. If they keep the lens to themselves, there is no problem. It becomes a problem when this home repair Leica lens lost its sharpness, it could be recycled back into the used market.

Therefore, when buying a used lens, the first thing is to carry with you a high power loupe, such as a Seibert Wetzlar Emoskop to check the screws for any sign of tempering; then check the lens interior to see any dust particles, if there are dust specks inside, it is a sure telltale sign that this lens had being "home serviced" , avoid it like plague.

The best thing is to buy Leica lens new.

-- martin tai (martin.tai@capcanada.com), June 07, 2001.

Lens disassembly is not that difficult and the air spaces mentioned above are set by the machining of the mount. If you really want to do this then invest in several repair manuals and the proper tools. Practice on some duffer cheap Soviet lenses. Personally the investment in tools and experience is not worth the bother as this only gives you the ability to clean lenses not colminate so you end up sending it off to get it checked any way. Cleaning a lens costs what $80 to $120US depending on the lens? Let someone who knows what their doing do the lens repair.

Cheers,

-- John Collier (jbcollier@powersurfr.com), June 07, 2001.

That sounds like a really good idea, Martin. It never occurred to me that someone might have botched an otherwise nice-looking piece of used Leica gear. Of course, I don't have a Seibert Wetzlar Emoscope, which sounds like it could be anything from a binocular microscope to a Hubble telescope. What are they, and what is the magnifying power? Would my Edmund Scientific 12X Loupe work? I do think that knowing your dealer is another good safeguard against bad gear.

Regards,

-- Bob Fleischman (RFXMAIL@prodigy.net), June 07, 2001.

Bob, Seibert Wetzlar Emoscop is an ingenious multi mangification loupe and handheld microscope all in one, invented by Arthur Seibert of EMO Seibert Wetzlar, whos other design included the famous COMPLAN lens for Minox. Emoskop has can be used as a 5x 10x 15x loupe and as 25x-30x microscope. And also use as a 2.5x mini telescope ! I use the 15x loupe mode to check negative, and use the 25x microscope mode to check for negative details, lens, jewellery, bogus money, etc.

I have also a made in Japan 20x loupe, the big difference in working with a 20x ordinary loupe vs a 25x Emoskop is the working distance, with ordinary 20x loupe, the working distance from the front of loupe about mm, too close for comfort, as one may accidentally scratch a lens surface, negative, or watch ; the Emoskop has a working distance of 25 mm, quite far apart from the speciment under observation.

The 2.5x telescope has a focusign range from 6 inch to infinity the 6" close focus distance is quite useful for some purpose; for instance some machinist use them to check working samples under a lathe.

Original made in Germany Seibert Wetzlar Emoskop is hard to find, some times shows up on eBay, made of metal, EMO Seibert later made a plastic version, still available on some site, selling for about $120-$130.

Part of the production of Emoscop moved to Hong Kong Emoscop.com

The price is quite low. People who use this new version said it is very good. I may buy two of this as presents to friends. It makes great gift

-- martin tai (martin.tai@capcanada.com), June 08, 2001.

Lens are actually easy to take apart and put back, a 6 element 4 group lens when dissasembled has only 4 goups, each in brass mount. It is also deceptively simple to put back.

I would be nice to have Leica interferometer, laser centering machine and computerized MTF machine to check out the 'assembed" lens. And a clean room too.

Leica lenses are expensive because of Leica's utmost precision --- one micron in thickness control and dead center in assembling of groups.

-- martin tai (martin.tai@capcanada.com), June 08, 2001.

Leica Camera Repair Handbook, by Thomas Tomosy has a description of lens disassembly for the 90/4 in fixed mount and collapsible mount. It also has descriptions for the 35/2.8 and 40/2.

US Army Publication TM 11-6720-244-35 – Camera, Still Picture K-15(4) – has complete descriptions for the second version of the 35/2. These two books are avaiable from new and used photo book dealers.

Cheers,

-- John Collier (jbcollier@powersurfr.com), June 08, 2001.