Cross threaded filter from impact damage

[megido]

Today I dropped my M3 and Summicron w/uv filter and screw in hood. The lens hit the ground face on and the filter crossed threaded itself with the impact. I've tried removing the filter by placing it flat on a piece of rubber and twisting but the front section of the lens unscrews itself instead. Any advice or tricks to help get the filter off? I'm not sure I want to unsrew the front section entirely so as to get a better purchase on the filter but it may be the last resort.
Thank you in advance

 

[peterm1]

You could try wrapping the junction between the front section and the lens barrel with gaffer tape or duct tape. This should keep them together. Just be careful not to hold onto anything like the aperture ring while twisting which might strain the aperture ring excessively.

A further trick might be to take something like a box cutter blade or Stanley knife blade and slide it into the space between the filter and the front of the lens at the point where the filter thread has "jumped it's tracks". If necessary use a small hammer to lightly tap the blade into the narrow space so it acts as a wedge. Twist the blade slightly to see if you can get the filter to go back into its proper thread allowing you to then undo it normally. I have done something like this to remove a stuck adapter I was using which jammed on the lens and which I was unable to remove by any other means. The wedging process of carefully tapping the fine blade into the gap and twisting if needed (remember it will only go in a millimetre or so till it bottoms out) is what does the trick.

A final trick, if the filter's glass is already broken from the impact or can in any event be removed (some filters have a spring wire or a screw in ring holding the glass in place) is to first get the glass out of the filter ring leaving only the circular metal frame of the filter still stuck in the lenses thread, then using a fine pair of needle nosed pliers / jewellers pliers etc to grip the metal rim of the filter in one spot, and forcibly (but in a controlled manner) bend it inwards at that point (into the space where the glass previously was located). This will disengage the metal filter ring from the thread in the lens. If necessary repeat it elsewhere on the ring. It ruins the filter of course but is a small price to pay in the circumstances. I have done this in one case I can recall where I had a similar problem. In my case the filter glass had disintegrated on impact. Of course care is needed to prevent scratches to the front lens element but this is not especially difficult. The metal of which filters are made tends to be aluminium and hence is pretty soft and easy to deform which is what you want in this case. (Its that tendancy towards deformation which probably caused the stuck ring in the first place.)

 

[Ranchu]

Make a little puddle of lighter fluid (naptha) in a bottle cap, dip a needle, syringe, or solid wire into it to collect up a small drop of fluid. Apply it to the crack between the two pieces so it runs in, and repeat around the filter. Try to turn it, there should be less friction anyway. Are you sure it's cross threaded? Is it tilted or dished in? If so, I think the filter glass will have to come out, and the filter ring removed by some other means than unscrewing it. You should consider talking to a professional if that's the case.

 

[johnf04]

I use the same method as Ranchu, to move sticky threads, but instead of naptha, I use mineral turpentine - it doesn't evaporate as fast, and it is very slightly oily.

 

[megido]

Thank you very much for your help.
Yes, the filter is tilted and looks like it has jumped a thread on one side. I'm going to take great care in any case as I don't want to damage the thread on the lens itself. That would be disastrous as the summicron in question is a near perfect collapsible. The filter is a brass (or at least looks to be) heliopan. I'm hoping that the thread on the Heliopan is softer than that of the lens threads. Part of me also thinks to just leave everything in situ and worry about it later!

 

[View Range]

The glass of the filter will have to be broken out. Obviously this has to be done carefully to avoid damaging the Summicron glass. Then the filter ring is grabbed with a pliers and twisted into an S shape. You don't have to twist very far to get the diameter of the filter ring to be small enough to come off. I would not even attempt to unscrew the filter.

You may want to send it to a repair shop like Focal Point in Colorado. The lens itself may need attention.

 

[Rob-F]

I like peterm1's idea of taping the barrel to prevent rotation. An alternative, if there is room for fingers, is to put a rubber band around the part of the barrel that needs to be held, and use the fingers on the rubber band to stabilize the piece. That can provide enough extra grip. Then proceed with the flat sheet of rubber on the filter.

 

[Dwig]

The glass of the filter will have to be broken out. ... I would not even attempt to unscrew the filter.
...

I agree. Unscrewing a cross threaded filter will likely increase the damage to the lens' threads.

With some filters, removing the glass from the front is not overly difficult, but with others it more of a challenge. I've removed many, many such filters. I've sometimes needed to resort to a jeweler's saw to slice the filter ring into segments. Breaking the filter has its dangers and I would recommend it only as a last resort.

 

[ABrosig]

Faced with several stuck filters, both with and without glass, when I worked in a camera store when I was in college many moons ago. We had a finely-tuned, precision instrument we used - a channel-lock pliers. Don't run cringing. Actually, the larger body, heft and bigger grip area of the channel lock seemed to make it more stable for grabbing the filter and enabled better application of pressure to compress the offending ring.

I'm not sure about older filters, but modern-day filters either tend to have a spring ring or a threaded ring, which screws into the front to keep the glass/element in place. These should be fairly easy to remove, which I agree with others should be done before attempting to remove the ring.

 

[rbiemer]

https://youtu.be/J4qI8RC7QrM
I am not seriously recommending this method but I don't like watching scary movies by myself. 🙂

Rob

 

[Fraser]

As already said if the filter ruined anyway just put a pair of grips on it. If its a brass filter shouldn't damage the threads to much, I'd be more worried that an element or elements have been knocked out of place.

Ps. Have you tried the old trick of using the hard rubber sole of a shoe? you could try that while keeping the lens together with a bit of gaffer tape.

 

[Ranchu]

Thinking about this, I have broken filters to get them out of the rings while they were off a camera using a soldering iron applied directly to the glass (40 watts). Heat was not a big concern with the filter off the lens. What you might try is heating up the center of the glass filter with a soldering iron until you can't hold the edge with your bare fingers, and then apply it to an ice cube to get it to crack. I've never done this on a lens, however, just thinking about how I'd go about it.

 

[Beemermark]

If the external threads on the filter are Ok; carefully remove the glass and leave the filter ring on. That way you'll have no difficulty using filters.

 

[megido]

After much thought, I think this may be a job for a technician. I'm loathe to use force to unscrew the filter which as mentioned could well damage the lens threads and breaking the filter could damage the front element. Unscrewing the glass from the ring could be an option.
As previously mentioned, i'm just somewhat concerned about not being able to screw a new filter on if damage occurs to the threads during removal of the existing filter. I have tried the rubber mat/gaffer tape trick but to no avail. If I had been using the dedicated 12585 hood the impact would not have disturbed the filter! Will keep you all posted. Thank you once more.

 

[ruby.monkey]

After much thought, I think this may be a job for a technician. I'm loathe to use force to unscrew the filter which as mentioned could well damage the lens threads and breaking the filter could damage the front element. Unscrewing the glass from the ring could be an option.
As previously mentioned, i'm just somewhat concerned about not being able to screw a new filter on if damage occurs to the threads during removal of the existing filter. I have tried the rubber mat/gaffer tape trick but to no avail. If I had been using the dedicated 12585 hood the impact would not have disturbed the filter! Will keep you all posted. Thank you once more.

Tape over the filter glass and use a dot punch to break it right at the edge; then cut through the filter rim as far as you can without harming the lens, before breaking/twisting the rim out with a pair of pliers.

 

[richardHaw]

for cross-threaded filters and those with dings, the only way for me is to destroy the filter by cutting it to 2-3 separate bits, removing the retainer ring and glass so I can finally pry off the filter casing from the lens 😱😱😱

I would rather have a ruined filter than a ruined lens. Be careful while doing this 🙄