There is a UV-filter screwed on my Canon 16-35mm. For some reason, I'm not able to get it off the lens. Does anyone has a simple but safe trick?
I carry a jar lid gripper around in my kit which has always done the trick for me when I need a little extra, well, grip.
The other 'trick' that I have learned over the years is that most people's default reaction to a stuck filter is to get a really good grip on the filter and just try to torque it off. The problem with this approach is that the filter glass is rarely a snug fit inside the metal filter rim. Because of this, gripping the filter firmly often results in the metal filter rim flexing ever-so slightly... Which binds it to the lens even more tightly. With such tiny threads a flexed filter might as well have lock-tite in there!
So it seems paradoxical, but often I've found that by loosening my grip and very gently turning the filter mostly using pressure on the top of the filter, rather than on the sides (which can cause it to flex) I can get it to turn.
If you're out and about and this happens then carry a couple of elastic bands! These allow you to get a proper grip on the slim sides of the filter so you can remove it. Often they are stuck not because they are jammed on but because you cannot get enough of a grip to apply enough pressure to start turning them.
A very simply, cheap, and more importantly small, solution that works quite well :)
You can buy lens filter wrenches -- if you don't think they'd be something you'd use all the time (and thus, buy), you might find that your local camera shop has one you could use.
When separating a stuck filters that are correctly screwed together the key is to be gentle and persistent. The filters got stuck because of the repetitive motion of turning the polarizer, they will get unstuck the same way.
What happens is that when you use force you bend the ring so the filters jam together more.
To get more grip, take a pair of thick rubber bands and put one arround each filter, that will help grip the very thin part of the polarizer that has the knurling. Gently twist the filters, grabbing at different parts of the ring to even out the distortion. A little push in and out (not rotation) can help wear down / dislodge any grit.
Illustration of undesired action:
You can get filter wrenches for exactly this sort of situation - just as you can for stuck tops on jam jars.
They can come in incredibly useful if you have a stubborn stuck filter. They are usually quite cheap and come in a range of sizes to suit the filter thread size you need...
One thing that has always worked for me in the field is to screw another filter on top of the stuck one. Screw it in pretty hard. This provides an extension of the outer surface of the stuck filter, enabling a much better grip with the fingers (or with a tool, which I have never had to use). Perhaps it also evens out small eccentricities in the stuck filter, helping it turn better within the lens's threads. The two filters together are also a much stronger assembly than a single filter, so there is less risk of cracking or deforming it. Once this pair of filters comes off the lens, it can be a little troublesome to separate the two filters again, but they tend not to be stuck as hard as the original filter was. A little patience always gets them apart. If not, you can work with it in the shop if you like without risking your lens; and your lens is back in service in the meantime.
If the rubber band or filter wrench doesn't work, the next step is a precision band saw.
If Adam Savage (the guy in the video) and his band saw is not available, you could also use a needle file or hacksaw to create a couple of notches in the front of the filter ring.
Once you've cut a couple of notches in the filter ring, you can use a steel rule to twist it off.
If the filter ring is too distorted to twist it off with the metal rule, you're going to need to remove as much of the filter glass as you can and then peel it off with a pair of (locking) needle-nose pliers. It may be easier if you cut all the way through the filter ring. Yes, that will nick the lens' filter threads. But if they are already warped they're going to need to be replaced anyhow.
When using a file, hacksaw, needle-nose pliers, etc. on the filter ring, it's not a bad idea to place a soft cloth over the front element of the lens to minimize the risk of scratching it.
If the lens hit something hard enough to warp the filter ring, the front element of the lens and filter threads are the least of your worries. The internal lens alignment needs to be checked.
For more about the overall subject of To filter or not to filter (for lens 'protection'), that is the question, please see this answer to is uv filter a must? here at Photography at Stack Exchange. There are lots of links to a plethora of questions/answers here and resources elsewhere on the subject. While there are times and places (sand/dust storms, at the beach, industrial settings with hot metal particles flying off grinders, etc.) where filters are useful for protecting the front of the lens, in catastrophic incidents such as yours they tend to be liabilities more often than not. A lens hood is normally better impact protection without any of the optical penalties of a flat glass filter.
safe for the lens or safe for the filter? Only time I've had a filter that wouldn't come loose with some force I took to breaking the glass on it and destroying the filter in place, then taking a wrench (now that I had enough grip) to force the empty thread off the lens.
Have to take some care of course but it's not that hard (in this case the front element was recessed deeply, making it a lot less dangerous to the lens).
One of the things to try is to lubricate the joint between the lens and the filter. You do NOT want to get liquids into the lens, so for doing all of these, keep the filter below the lens body.
I would go further and put most of the lens in a plastic bag, and masking tape the edge to the barrel behind the filter.
Things to try:
Lens cleaning solution. This, I think is basically distalled water and photo-flo, a wetting agent.
Soapy water. I think the best solution would be glass cleaner -- windex or equivalent.
Ether. You can get canned ether at auto stores for starting reluctant engines.
WD-40. This basically fish oil and ether. The ether acts as a carrier so that it can penetrate.
Penetrating oil. This is usually a mix of what amounts to light machine oil in a carrier of hexane
Ether and hexane potentially are solvents for whatever lubricants are in the lens. As solvents they can move the lube to different places. Ether is explosively flamable. Do not do this in a confined space, or near a source of ignition.
If you want to use the heat technique, but don't want to risk condensation on your lens, try this:
Park the lens in a sunny window. You want it warm. Doesn't need to be hot.
Take a cup of hot water and dissolve as much salt as you can.
Freeze the salt water in a bowl.
Once frozen solid, remove from freezer, knock the ice out of the bowl and put on the counter flat side up.
Press the filter against the ice for 10 seconds.
Attempt to remove filter.
Repeat with 20 seconds.
If it hasn't worked by the time you get to a minute, back to the drawing board.
Aluminum conducts heat quite well, but the threads don't conduct heat as well. You are trying to cool the filter faster than you are cooling the threads on the rim.
Having a warm lens increases the temperature differential and so increases the size difference.
Cautions: Salt water is corrosive. Do NOT get this in your lens.
If this makes you nervous, you can partially fill a bag with alcohol. It won't freeze, but it will get to whatever the minimum temp of the freezer is.
If you are willing to sacrifice the filter, you can cut a notch across the middle of the filter. (A thin piece of cardboard protects the filter if you want to try to keep it.)
If you use a hacksaw, the resulting notch will be about 1/16" wide and between 1/16 and 1/8 inch deep. 1/16 is enough.
Now out to the garage. You need to pieces of wood, 1x2 is fine. You also need a hacksaw blade. Old one is fine. You will need a couple of #4 or smaller screws. Several 1.5" #8 screws.
- Cut one piece so that it is about 3 inches longer than the hack saw blade.
- Lay the hacksaw blade on this chunk so that the back edge (no teeth) over hangs the edge of the board by a bit less than the depth of the cuts in your filter rim.
- Screw the blade to the board.
- Cut the other board so that it's shorter than the blade, and doesn't hit the screws.
- Screw the board to cover the blade from the other side, leaving the same amount of blade showing.
- Now you have a tool that fits the slots. Put the body cap on the lens, and have a helper hold the lens firmly on a table.
- Fit the protuding edge into the notches and twist off.
If you are alone, and have a vice, you can put the tool in the vice and twist the lens.
A comment points out that using a steel machinists rule would make more sense than my used saw blade tool. But: I didn't have one. I didn't think about it. And the blade was the right width for the notch.