In the last post, StevenPA says he used a Cokin P-holder attached to a 60-62 step-up ring but there was some vignetting.
Since I don't have any experience with Leica R lenses, I'm not sure what happens with this lens when zooming and focusing. Some Leica R's seem to have front parts that recess inside internal hoods and, although the 35-70/4 hood is removable, I'm just curious to know if the filter thread is accessible at all focal lengths when the hood is removed?
The 35-70 f/4 ROM Leica's inner ring/diameter which contains the lens elements does indeed move both beyond and behind the outer focussing ring.
If you use a stepping ring it will restrict the movement significantly. You can get infinity focus from 35mm to about 43mm, after that the inner ring "goes turtle" and slides inside the barrel, never to re-emerge while set to infinity.
For reference, at about 50mm with the focus set to 3.6' or so, a stepping ring will work - barely.
However, at minimum focus distances, the inner element barrel will always stand proud of the outside barrel focus ring...but that's of little use for what I assume you're doing: shooting landscapes with a filter system of greater diameter than E60.
Frankly, the use of the E60 diameter and this hide-and-seek barrel/cam movement really limits the use of anything except an E60 diameter. The inner barrel rotates about a quarter-turn when you rack from near to far. I guess you could go the Rube Goldberg route, and stack a bunch of E60 rings to make a "tube" that protrudes just far enough past the outer barrel at your chosen maximum focal length, so that you can then add a stepping ring, but...why?
Taken as a simple R-mount lens, though, it's pretty good performer. It has good color and sharp rendering without too much color fringing either axially or laterally when shot wide open. The macro function adds a lot of versatility as well. It's a great all-purpose lens in most any respect, but of course is engineered to certain spec which means you get all the wonky external movements, with barrels sliding and rotating like any Canon kit zoom.
And I agree with Steve's assessment of the cap - it's a slip-on type that is ludicrously bad, plus it has a convex front so you can't really place a lens/body combo face down with it on, lest it topple.
Thank you very much! This really helps me visualize how this lens works.
If I can bother you for a little more info, do you happen to know how far the inner ring goes inside the barrel? If it's a couple rings then I might be willing to try it but if we're talking the distance equivalent of a half dozen rings then I would probably leave it alone. I'm thinking of using the lens on a 4/3 or m4/3 body so I would be able to get away with a bit more than if it was on FF. I also expect I would use it more from 35-50 regardless of any filter difficulty.
70mm, at infinity focus is the deepest the inner barrel goes. At that point, I'm guessing you'll need at least two, perhaps three uniformly E60 rings to get out of the "well", to where a stepping ring could be fitted.
The good news is that's at 70mm, at least.
With all due respect - aren't there better options out there? The 35-70 is not a bad lens but it certainly doesn't blow me away in any respect. It's not like it's a Summicron 180 or something that has truly unique and or/beautiful imaging properties.
Just get an E60 UV filter with and extended ring (BW makes one) and front threads. Then you can add a filter holder without clearance issues. Or handhold the filter. That's what I do.
Thanks for the additional responses and sorry I didn't get back to this thread sooner. I decided to pass on the Leica and go with a Tokina 28-70 (the f2.6-2.8 II version).
