Removing Haze from Leitz 35mm F/3.5 Summaron Lens

As mentioned in my previous write-up, my Leitz 35mm F/3.5 Summaron was plagued by haze on the internal elements which caused fairly bad flare in images taken with it, particularly when shot toward any bright light. It’s a common ailment with this particular lens, and can ruin what is otherwise an excellent performer. With this in mind, I decided to tackle stripping down and cleaning the lens myself. Fortunately, the whole process turned out to be relatively easy.

Remove the three marked screws and the retaining ring.

Removing the three screws above from the rear of the lens mount allows the entire lens module and diaphragm assembly to be removed from the lens focusing mechanism. I then used a rubber sink stopper to unscrew the rear lens module retaining ring, giving me access to the internal surfaces for cleaning.

The dismantled lens. The lens cap is useful for holding the removed screws.

I didn’t want to remove the diaphragm mechanism because I’d heard horror stories about reassembling it correctly, so I set it to the largest opening and carefully used a Q-tip with a few drops of lens cleaning fluid to treat the inside of the front element.

I accessed the inner front element through the aperture diaphragm

All the glass cleaned up remarkably well and, after getting rid of any stray dust using a Rocket blower, I put it all back together. The lens now looks great. There is a small area on the inner rear element that proved pretty stubborn, so a tiny amount of haze is still visible on careful inspection, but it’s a huge improvement from what it was before the cleaning, where the haze covered nearly 100% of the glass surface.

The reassembled lens, with sparkly clean glass!

The ultimate test was to run a film through my Leica M3 with the Summaron attached. Below are a few of the frames from that roll, many of which are shot toward the light. Comparing these to the shots in my original article, it’s obvious that it now performs much, much better in these situations, retaining good contrast throughout the frame, with only a small amount of veiling flare.

Leitz 35mm F/3.5 Summaron test roll
Leitz 35mm F/3.5 Summaron test roll
Leitz 35mm F/3.5 Summaron test roll

Overall, I’m very pleased! Shooting with the Summaron used to mean being very mindful about framing so as not to include any bright light sources, and this made me less inclined to use it, but a simple cleaning has turned it into a lens that I think will now find itself attached to my M3 a lot more often!

15 thoughts on “Removing Haze from Leitz 35mm F/3.5 Summaron Lens

  1. How did you manage to keep the focus calibration?
    I’m afraid that if I do this to my Summaron, I’ll end up messing up the focus…..

    1. I didn’t touch the focusing helicoid as it was smooth and didn’t need cleaning or re-greasing, so focus wasn’t affected at all. I would also have been wary if I would have had to mess with that!

  2. Hi Dave,
    Firstly Amazing!

    I have a similar Summaron that has the haze plague. I am keen on opening it up to clean it up like you. I have cleaned a few lenses.

    I am hoping you could elaborate a little more.When you say “couple of screws on the rear of the lens mount”. The only screw I see anywhere close to the mount is 1 on the focus ring -very close to where it says “Germany”.
    Wishful thinking on my part , but it would be great if you could upload a more detailed cropped image with labels pertaing to the steps involved or location of screws.

    I hope I am not too demanding -I hope you understand. I appreciate any extra details/input,

    Regards

  3. That’s really cool!
    I have a summaron m 35 3,5, but not the same of yours (don’t have screws on the back). And I have some kind of gazoline trace on the front element, maybe some oil that came out. I really don’t know how to procede to clean only the front elements. I was wondering if I could send you some pictures?

    1. Someone else also mentioned that their Summaron didn’t have the screws that mine does, so it seems there are more than one version. Unfortunately, I’m not sure I can help, as I wasn’t able to get in through the front of mine; I managed to clean the front element from behind after removing the rear elements. Feel free to send some pictures though, and I’ll see if I can look at mine again and suggest something (dave@djcphoto.com).

  4. Hello Dave,
    my name is Michael from Germany, at first: excuse my poor english.
    I read of your article about shutter problems with pentax 6x7which was very instructional.

    Possibly you have an idea about my problem:

    Pentax6x7 from 1969, working correctly with excellent results, but then:

    three exposures with 1/8 s, shutter stuck, mirror upside,
    changing battery—pressing release, pressing shutter — nothing happens— battery empty in one minute
    next new tested full battery —same procedure —- battery empty
    in both cases red light disappeared
    battery prooved in provider shop really empty

    Do you have an idea?

    Thank you very much

    Michael

    1. Hi Michael,

      Sorry, I have not come across that specific problem, but it sounds like a short of some kind if your battery is being drained that quickly. If you haven’t already, I would try cleaning the battery contacts, and maybe removing the cover mentioned in my article to make sure nothing is corroded. Other than that, I’m afraid I don’t have any more suggestions.

      Good luck,

      Dave

  5. I have an image I’d like to show you deliberately taken to produce haze so I could tell if my lens needs cleaning. It is the sun peeping through some high, somewhat dense branches. Could you look at this image and advise me? I am just about to upload it to plexipages.com/branches.jpg. Thank you!

  6. Hi Dave,
    I began the procedure of disassembly but I could not go beyond trying to remove the back Lense with a rubber sink. It seems to be too tight. Can you please explain in more Detail how you get this retaining Ring unscrewd? There ist for me a black frame in this step.
    Lot of thanks however for your Tutorial.

    1. Apologies for the late reply. It has been a long time since I had the lens apart, but I will try and take a look at it again this evening to see if it jogs my memory. I would not want to give potentially incorrect information without checking my procedure first.

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