Recently I bought a used Leica 90mm f/4 Elmar-C lens. When I asked the filter size the sellar told me Series 5.5 drop in which was quite rare. I was also told I could buy an adapter from Series 5.5 to 39mm. So I did a bit of online checking and found several posts saying the same. And one or two saying 39mm filters might work but be a bit loose. So I found and bought a series 5.5 retaining ring to replace the one missing from the lens. And I also bought a 39mm UV filter thinking I could cut off the ring and use it as a drop in filter as someone posted doing.
So everything arrives in the mail. The lens come with a metal 39mm sunshade and 39mm plastic pinch lens cap. Both fit fine.
And the series 5.5 retaining ring and my 39mm filter also fit fine. In fact I’m going to use the 39mm filter with the series 5.5 retaining ring acting as a small shade.
What I am confused about is all the posts on several forums which said this lens needed the series 5.5 drop in filter and that you needed an adapter to use a 39mm screw in filter.
No, the filter seems very secure. The retaining ring acts like a very small shade and protects the filter. The metal 39mm no name shade that came with lens is over an inch long. I bought this lens since it is very compact, not so with that shade. I can always use my hand if I am getting any glare.
The Series 5.5 and 39 mm thread have a different pitch. The 39mm filter may fit partially or completely, but it would undoubtedly damage the pitch of the lens thread. If you aren’t going back to 5.5 it may not matter.
I’m not going to change anything. Actually the lens came with the 39mm shade attached and the 5.5 retaining ring still worked with problem.
But thanks for the information.
