p.18 #2 · Official: Voigtlander 35 F1.7 Ultron M mount
mapgraphs wrote:
This is the more plausible explanation.
The original LTM came in at least two cosmetic variants, with differences in the knurling on the focus ring. There was a claim that the so-called later version wasn't prone to the problem with the cement deteriorating (haze) but subsequent observations suggest that all of the LTM versions can exhibit haze.
It also appears that some copies do not have an issue with the cement. I have both versions, one has haze the other is clean. It may be an issue of batches, some used better cement, most didn't. Excellent lens though, even with haze....Show more →
I believe cement deteriorating (haze) is the issue and it seems to be common with all the ltm 35mm f1.7 after a certain age. are you saying you have both versions of the ltm? I am curious if there is anyone here who has the ltm version that does not have this issue. Some of the older 40mm f2 ultrons (Ultron 40mm f/2 SL (2002–2003)) have this issue too.
After more testing the haze flaring is a major issue, noticeable even in indirect light on bright objects. All reflective objects have a heavy hazy glow around them as if i were using a 1/2 or 1/1 diffusion filter. I suppose I could relegate it to being my "character lens". Also the 0.9m MFD limits its usage heavily. I would generally avoid the ltm (L39) version of this lens unless you can return it easily or inspect before buying.
p.18 #3 · Official: Voigtlander 35 F1.7 Ultron M mount
I think a lot of the Voigtländer LTM lenses from this general era have haze. For example the 35mm 2.5 Color-Skopar often has haze (I looked for six months to find one without haze and it has remained haze-free so far). I thought it was due to offgassing oil/grease but maybe it's from deteriorating cement, but it does seem to be a common affliction of older Voigtländer LTM lenses.
p.18 #4 · Official: Voigtlander 35 F1.7 Ultron M mount
From some comments on RFF, one thread went through the 35 Ultron issue in some detail, in general it sounded like a cement issue. Apparently (anecdotal) Cosina said they couldn't fix it. I have a bunch of LTMs, 15, 21, 25, 35 (the Ultron), 40 that are all clean. A more consistent issue with Cosina (at least the older lines) seems to be element asymmetry.
p.18 #5 · Official: Voigtlander 35 F1.7 Ultron M mount
I had 2 of the 35/1.7LTM's. Still have a black one and it is does have slight haze and wobble, not really bad though. It is a lowish contrast lens which does compound the issue. I used to have a silver one when it was first released, which I lost, which I always thought was better made and took better pictures. Still sore I lost it, loved the organic 3D rendering. Had to remember to use it above f2 though where it was sharper. Also still have a 50/1.5 and 21/4 from the same era, both have no haze issues. The 50 needs a regrease and the 21 is decentered, though I'd never noticed on film. Still use the 50 on Sony occasionally but the minimum focus distance is a bit annoying. Great lens though for shooting at night.
I'm no expert, so maybe wrong, but looking at the lens diagrams I do think the later 35/1.7VM is a development of the earlier LTM with an extra element, and better coatings and manufacturing etc. rather than a completely different optical design. The 35/1.7VM is vastly better than the LTM though, from quite different Cosina eras. I'm quite sentimental about my Ultron and BessaR, I couldn't afford a Leica and wanted to shoot B/W film because digital was crap back then. I was quite happy.
p.18 #7 · Official: Voigtlander 35 F1.7 Ultron M mount
mapgraphs wrote:
From some comments on RFF, one thread went through the 35 Ultron issue in some detail, in general it sounded like a cement issue. Apparently (anecdotal) Cosina said they couldn't fix it. I have a bunch of LTMs, 15, 21, 25, 35 (the Ultron), 40 that are all clean. A more consistent issue with Cosina (at least the older lines) seems to be element asymmetry.
I thought the 21/1.8 and 35/1.2 v2 were both pretty good and around the start of when Cosina improved over their ~2010 and earlier offerings. Since ~2015 with lenses like the VM 15/4.5 v3, VM 35/1.7 and the APOs, my impression was that Cosina was very close to Leica for optical performance. They haven't really released a dud lens in ~10+ years, though some have been less strong than others.
p.18 #8 · Official: Voigtlander 35 F1.7 Ultron M mount
bijosn wrote:
If anyone has any advice or links to any disassembly instructions for the the ltm version it would be greatly appreciated.
I don't think I could never find specific instructions when I wanted to service mine. I was going to jump ahead and just try whilst I was cleaning other lenses, but as mine aren't too bad I didn't end up doing it.
I may have cobbled together some vague references for the 50/1.5 but can't quite remember now. If you can find instructions for the other larger LTM's from the same period they may be similarly constructed.
I think this guy on YouTube is worth watching for servicing lenses, getting a general handle on the mechanics etc.:
p.18 #9 · Official: Voigtlander 35 F1.7 Ultron M mount
ArveyAll wrote:
I don't think I could never find specific instructions when I wanted to service mine. I was going to jump ahead and just try whilst I was cleaning other lenses, but as mine aren't too bad I didn't end up doing it.
I may have cobbled together some vague references for the 50/1.5 but can't quite remember now. If you can find instructions for the other larger LTM's from the same period they may be similarly constructed.
I think this guy on YouTube is worth watching for servicing lenses, getting a general handle on the mechanics etc.:
