Every user of the Voigtlander FE 65mm f/2 APO-Lanthar Aspherical should be aware of just how damaging this issue is. It repeatedly ruined quite a few series of mine before I figured it out.
Lubricant in the Voigtlander 65/2 APO focusing helicoid has too little friction, allowing gravity to slowly “walk” lens focus when the lens is at any inclination.
I detail the issue and how to diagnose it, along with potential mitgations:
I ran into this problem when shooting the fruit platter evaluations. Once I finally figured out that I hadn’t screwed up and that there was no good solution, I ended up switching to the Voigtlander FE 50mm f/2 APO-Lanthar Aspherical, which looks to be free of the issue.
Probably the heavier internal lens elements in the 65/2 overwhelms the friction of the lubricant. IMO this is an obvious design/build defect. But worse, it’s clear that Voigtlander failed to do adequate and IMO rudimentary testing to detect what should be an obvious consideration with any macro lens, which almost by definition means tripod use at an inclination.
I don’t know if Voigtlander will service the lenses to fix this issue and I don’t know if currently for-sale lenses also have it (I got mine a few years ago).
Michal J writes (wrote):
I’m very curious about your mention of Voigtlander 65 defocusing itself. I have that lens and I love it. I literally shoot like 95% of my stuff with it these days. Yet, every once in a while I have a lot of ruined shots from unexplained defocusing.
I usually am nailing focus on it no problem and then suddenly I have shots that are completely ruined. We are not talking about missing a focus by a meter or two. We are talking focus is nowhere to be found on the photo, or I’m shooting something 15 meters away from mm and focus is 50 meters behind it.
And this is with carefully focusing wide open in magnified view and all that. Could never figure it out, though I have a feeling it might have something to do with temperature. I’ve recently took a walk on a snowy day in the woods and all the shots from the beginning of the walk are ruined and then suddenly they are all good in the later part.
The next day I have even caught it doing something weird. I was focusing at f2 closing down to shoot to 5.6, but then when I wanted to verify something and went back to f2 the focus was not there anymore.
I could repeat that same behaviour a few times, but then it stopped and everything was fine again. I’ve only noticed this behaviour outside in cold weather, so I figured maybe something with the barrel of the lens adjusting to conditions or something of the sort.
It is troublesome to me, I’ve lost some great shots to that and you never really know when, cause most of the time it’s either perfect or I can blame it on myself. I do hope that you’ll post more about your mishap, maybe it’ll inform my situation as well.
DIGLLOYD: Michal wrote the above in reference to yesterday’s note and today I wrote the post and page above.
At distance, a very small change in focus does in fact mean the difference between 15m and 50m focus. At close range it might mean 1cm. This is trivially easy to learn/see in magnified Live View.
Samuel Chia writes:
I saw your report about the CV65/2 focus creep. I have experienced the same problem myself, and the rotating-aperture-ring-changes-focus problem is indeed what I've experienced too, even when the lens is pointing straight and forward, not only when angled up or down.
I think I learned about this solution from Joseph Holmes who learnt it from a friend. Or maybe not. One places a wide-band rubber band overlapping the focus ring and the lens barrel to increase the rotational resistance. Cheap, and it works. I don't know what sizes of rubber bands are convenient for you to find, so a bit of experimenting is probably in order to find the optimal resistance to your hand. I happened to have this blue one in a box of knick-knacks lying around that fits. No idea where it came from! Here's what it looks like, hope this helps (picture at right).
DIGLLOYD: the rubber band seems likely to do the trick, though possibly it could allow allow micro changes via just a bit of “sag” into the resistance.
Stephen Gandy of Cameraquest.com writes:
From your description the lens is not broken, but does need maintenance.
Contact your dealer. Voigtlander servicing is done thru the USA dealer that sold the lens.
DIGLLOYD: this is a mint-condition lens about 3 years old with silky smooth focusing. It’s news to me that lenses just sitting in a drawer 99% of the time need “maintenance” for lubricant that feels identical to the day I bought it.
I’ve contacted Cosina in Japan directly (via “Importers wanted Contact us” email*) for clarification on the lubricant issue. But whether the issue is even recognized is an open question, and therefore it might be that Voigtlander has no alternative lubricant and therefore the rubber-band fix as per Samuel Chia is the only realistic option.
Stephen Gandy runs CameraQuest.com, one of two offical Voigtlander USA Distributors in the USA. I’ve responded by asking him to clarify if he is a "dealer" (since his site sells the full range of Voigtlander lenses) and whether therefore a lens could be serviced if it had been bought from CameraQuest (answer appears to be yes).
UPDATE: Stephen Gandy of CameraQuest.com says that B&H-sold Voigtlander lenses are via The Photo Village and that they can be serviced there. But take a look at Cameraquest.com for Voigtlander lens purchases also.
* note says “Please note that we might not reply to any inquiries from free email service account, and/or any inquiries not related to distributing Voigtlander products. Please contact near-by stores/distributors for products information and after service.”