MarkWalberg
Established
I have an Elmar 50/3.5 whose focus is truly stuck, a bit short of infinity.
I've cleaned the accessible threads, and I've soaked it in naptha for several days, and now I've had it in penetrating oil for a few days.
Still will not budge. Does not look bent. I took the infinity lock off.
What to do when it is stuck so solid?
I've cleaned the accessible threads, and I've soaked it in naptha for several days, and now I've had it in penetrating oil for a few days.
Still will not budge. Does not look bent. I took the infinity lock off.
What to do when it is stuck so solid?
Did it ever work? Can you post some pictures?
It sounds like the threads might be damaged. The 5cm F3.5 Elmar is a simple single-helical design. If it was old lubricant, what you did should loosen it.
About all I can think of is to try some rubber pads to get a good grip.
It sounds like the threads might be damaged. The 5cm F3.5 Elmar is a simple single-helical design. If it was old lubricant, what you did should loosen it.
About all I can think of is to try some rubber pads to get a good grip.
MarkWalberg
Established
The only situations I've had: 1) cross threaded, but I doubt that is the problem here. The threads are coarse. 2) Something jammed into the threads. I have seen set screws get into the mechanism. You can try solvents, and heating the metal.
If it is a screw or something else jammed in- force is about the only thing I can think of that works.
If it is a screw or something else jammed in- force is about the only thing I can think of that works.
peterm1
Veteran
I would not use vinegar because of the risk of causing corrosion to the metal and the inability to flush it entirely if it fails.
BTW I hope you have removed the lens elements so there is only metal to worry about.
I agree with Sonnar Brian that what you have tried already should work, I have never known it to fail.
Which leads me to think that maybe the problem is indeed mechanical - if the lens shows no obvious signs of physical damage as you say, a couple of other possibilities arise, I suppose - just thinking it through as I write........
One is that it may have something to do with the helicoid key - a small usually rectangular piece of metal which is driven up and down in a keyway slot driving the lens in and out as the focus is adjusted. I wonder if there is some way this could have been jammed or if the screw holding it in situ has been driven in too tightly. (a guess) ????
Alternatively, one other thing comes to mind - if there were no grease in the helicoid one further possibility presents itself - corrosion of the threads are preventing movement. (It's a guess but these lenses are so relatively simple in their design it is hard to see what else could go wrong. (I do not presently have an Elmar 50mm any more - I had one but had a look at my old Summitar which has a somewhat similar construction. The thing about these types of lenses is that the rear of the lens and its internals tend to be very exposed to the elements and possible ingress of crap.
One final thought. Assuming all the glass is out of the lens a further thing you might try is to gently (GENTLY!) heat the body of the lens to see if this has an effect either by softening any hardened grease or by breaking the bonds of any corrosion that might be locking it in place. It sounds radical and is so needs come caution and care plus willingness to accept it could be damaging if overdone.
Not sure if there is anything in these threads that helps.
The first is a step by step guide to working on the Nikkor 50mm f3.5 collapsible which is a close cousin to the Elmar and appears to be based on it. There may be some hints in it which help to the extent that they have similar construction. The guy who writes this series of guides is very good and his info is pretty comprehensive and useful. It's not exactly on point but its the best I have found online so far.
Repair: Nikkor-Q•C 5cm f/3.5 (Collapsible)
What’s up, everybody? I am loving the weather now because Spring is nearly here! Here in Japan, we will celebrate the Spring Equinox next week. I’m sure glad that the seasons come and g…
richardhaw.com
And here is a discussion on what other people have tried to deal with overly stiff helicoids in this lens type.
50mm Elmar -- stiff focus
Great looking lens arrived today with great looking IIIF RD ST. Lens focus stiff: what, if any, lubricant, could I put on threads, albeit in a minute quantity on a Q-tip?
www.photo.net
Disassembling the Elmar mount should be identical to the Industar-50, which I photographed:
rangefinderforum.com
I've done the same with my uncoated Elmar and post-war Elmar.
Industar-50 Lube and Adjust
This Industar-50 is a Tessar formula 50/3.5 in a brass mount with "very shiny Chrome". Performance compares well with the post-war 50/3.5 coated Elmar. The I-50 is the third formulation of the 50/3.5 Tessar in the Industar series, it improves on the optics of the Industar-22 and Industar-10. The...
rangefinderforum.com
I've done the same with my uncoated Elmar and post-war Elmar.
MarkWalberg
Established
Yep, Should be easy. I just need stronger arms.
I bought this lens about 20 years ago on eBay, but haven't tried to get it working until now.
It reminds me about the Canon 50/0.95 that I also bought back then. When it arrived, the glass was great, but the focus barely moved at all. I sent an email to the seller thanking him for selling the lens, and that I was lucky that I already had a pipe wrench to focus it.
No, I did not use a pipe wrench. I took it apart and cleaned it. Works fine now. Thanks for the tip, Brian, for the adapter to put the Canon on my Z6.
I bought this lens about 20 years ago on eBay, but haven't tried to get it working until now.
It reminds me about the Canon 50/0.95 that I also bought back then. When it arrived, the glass was great, but the focus barely moved at all. I sent an email to the seller thanking him for selling the lens, and that I was lucky that I already had a pipe wrench to focus it.
No, I did not use a pipe wrench. I took it apart and cleaned it. Works fine now. Thanks for the tip, Brian, for the adapter to put the Canon on my Z6.
DLox
Member
Peterm1 said #5:-
One is that it may have something to do with the helicoid key - a small usually rectangular piece of metal which is driven up and down in a keyway slot driving the lens in and out as the focus is adjusted. I wonder if there is some way this could have been jammed or if the screw holding it in situ has been driven in too tightly. (a guess) ????
These Elmar lenses do not have a helicoid key, the whole lens barrel rotates with the focus screw. One potential problem gone!
Little else remains but a jammed thread. If a 'correct' approach does not cure it then the 'engineering' approach would be based on unmitigated violence!!.
First remove the front lens flange (someone will surely know how to do this (I hope!)); care not to allow the lens elements to distribute themselves over the planet. The complete focusing mount can then be slid off the front of the lens barrel. This will make it easier to work on the unit with no danger to the the lenses.
As Peterm1's caveat, NO corrosive liquids. Much Patience and the freedom to apply, IF needed, more than reasonable force, the whole thing can be submerged in penetrating fluid BUT this may well remove all the paint as well. NOT such a good idea! If penetrating fluid can be applied sparingly to the threads withe assembly lying flat and the edge of the mount ring tapped with two copper or brass faced hammers across a diameter moving around the unit you might be able to shake it free. It might take a day or two.
One is that it may have something to do with the helicoid key - a small usually rectangular piece of metal which is driven up and down in a keyway slot driving the lens in and out as the focus is adjusted. I wonder if there is some way this could have been jammed or if the screw holding it in situ has been driven in too tightly. (a guess) ????
These Elmar lenses do not have a helicoid key, the whole lens barrel rotates with the focus screw. One potential problem gone!
Little else remains but a jammed thread. If a 'correct' approach does not cure it then the 'engineering' approach would be based on unmitigated violence!!.
First remove the front lens flange (someone will surely know how to do this (I hope!)); care not to allow the lens elements to distribute themselves over the planet. The complete focusing mount can then be slid off the front of the lens barrel. This will make it easier to work on the unit with no danger to the the lenses.
As Peterm1's caveat, NO corrosive liquids. Much Patience and the freedom to apply, IF needed, more than reasonable force, the whole thing can be submerged in penetrating fluid BUT this may well remove all the paint as well. NOT such a good idea! If penetrating fluid can be applied sparingly to the threads withe assembly lying flat and the edge of the mount ring tapped with two copper or brass faced hammers across a diameter moving around the unit you might be able to shake it free. It might take a day or two.
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Livesteamer
Well-known
Consider the use of heat. First, as others have said, remove the optics. Second, put the jammed parts in the freezer for an hour or so. Have some very hot water coming out of the faucet, remove the stuck assembly from the freezer let the hot water flow over the outer flange. The goal is to make the inside shrink with cold and the outside enlarge from heat. Good Luck. Joe
MarkWalberg
Established
Success. It took a lot of force. I had to use big wrenches with rubberized jaws.
A bunch of solid green stuff is what had glued them together.
I lubed with vacuum grease left over from my ultracentrifuge days.
The hardest part was getting the barrel back into the helicoid over the light baffling felt.
Thanks for the help.
A bunch of solid green stuff is what had glued them together.
I lubed with vacuum grease left over from my ultracentrifuge days.
The hardest part was getting the barrel back into the helicoid over the light baffling felt.
Thanks for the help.
Attachments
peterm1
Veteran
The "solid green stuff" sounds very like verdigris - which comes from corrosion of brass, copper etc. It is more or less powdery when broken apart and is sometimes a blue green hue.
"................ a bright bluish-green encrustation or patina formed on copper or brass by atmospheric oxidation, consisting of basic copper carbonate."
MarkWalberg
Established
Probably is some kind of verdigris. The threads are brass.
It came off as long thin pieces the shape of the focusing threads. Did not dissolve in vinegar.
I've cleaned a lot of verdigris from brass intstruments (mostly trumpets) over the years.
It came off as long thin pieces the shape of the focusing threads. Did not dissolve in vinegar.
I've cleaned a lot of verdigris from brass intstruments (mostly trumpets) over the years.