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.
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.
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.
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 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.
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!