Best way to remove a stuck filter?

<p>Hello to the Great Worldwide Photo.Net Community.<br>

I just acquired an old but still functional Pentax P3n 35mm film SLR. It has a Sigma Zoom Master 35-70 f3.5-4.5 Multicoated zoom lens. The lens zoom ring appears stuck or jammed, and does not rotate normally. It is stuck at about the 65mm focal length, thus making it a 'fixed' lens, unless I repair it. However, I can live with that for now,since 65mm still gives a reasonable 'normal' view.<br>

The lens has a 52mm screw-on filter attached. It's a HOYA 52mm SKYLIGHT 1B, made in Japan. The filter is very well screwed on, and has been on there for who knows how many months. I cleaned the outside surface of the filter and now its clean. I would like to remove the filter and clean the inside surface and the front surface of the lens.<br>

My first attempt to unscrew the old 52mm filter failed horribly. I rotated the manual focus ring to extend the lens out as far as it can go, then held the manual focus ring still, with my right hand, while I tried unscrewing the fiter with very firm pressure from my left hand. To my horror, I only succeeded in unscrewing and removing the front half of the Sigma 35-70 lens. That 52mm Hoya filter refused to budge. Undaunted, I carefully screwed that front lens group back in and tighted it with hand pressure. The Hoya filter is still in place.<br>

My question is, what's the best way to remove that stuck filter w/o doing further shock to the Sigma lens? I got the whole kit for $5, so I don't have lots of money invested, but I still want to remove the filter and clean the front lens.<br>

Thank You for any helpful answers.<br>

AP<br>

Atlanta GA</p>

Flat. Straight-on to the lens.

 

Use a rubber mat. Place the lens, filter down, on the mat and unscrew it.

 

Any side pressure tends to make the filter go out of round and can actually make it tighter.

 

If you have to, use one of those band wrenches. They have a handle and a loop of tough, dense rubber band like material. The work well for holding onto round things that are somewhat delicate.

<p>There are at least two things making this filter hard to remove. Hoya rings are made of aluminum, which tends to gall or corrode. Secondly, when you squeeze the sides of the filter, it distorts the ring making it tight in other places.</p>

<p>You can't do much about corrosion (if it exists). Don't even think about penetrating oil, or your repair problems will just be starting. Pressing straight down on a rubber or cork mat applies even force which may get the job done. However, it doesn't offer much turning force.</p>

<p>A camera repairman would use a filter wrench (or make one) which has a split ring the same size as the outside of the filter. When tightened, the clamping force is very even and high enough to turn the most reluctant filter. You could make one out of a sheet of 1/4" plastic if you have a band saw, drill press and a fly cutter.</p>

<p>Try using light pressure first instead of brute force. It seems counterintuitive, but it's worked for me a few times. </p>

<p>Take the lens off the camera so you have a nice cylindrical object that you can hold and turn in one hand. </p>

<p>Gently take hold of the filter with your entire other hand, meaning the pad at the base of your thumb flattened along the edge of the filter as well as all your fingers spread over the rest of the filter edge. You really shouldn't be worried about fingerprints or handprints on the filter at this point.</p>

<p>Give it a gentle counter-clockwise twist. </p>

<p>Then release the filter and spin the lens a bit in your hand so you won't grab the filter in the same spot and try again. </p>

<p>After a dozen repeats you may be pleasantly surprised when the filter just suddenly comes loose. </p>

<p>If it still didn't come loose, then repeat the procedure another dozen or so times, but this time give the filter a slight clockwise and then a slight counterclockwise twist before turning the lens.</p>

<p>It works pretty well while you're watching tv as you can do it absentmindedly and you won't get bored. If it doesn't work at least it didn't cost you anything to try it. Do report back if it worked though. </p>

<p>Alan, if all else fails you can buy this kind or wrench or as Edward says make one. I did just that out of some very hard rubber stock (0.5 in thick) the factory had lying around. It is merely a hole saw cut out with a slot to allow for compression. No magic and superior grasp without deformation and surprising mechanical advantage. Plywood, plastic or other material would work too I suppose.</p>

<p>http://www.adorama.com/FLFWB.html?searchinfo=filter%20wrench&item_no=1</p>

<p>Jim M.</p>

<p>One old trick is using one of those "rubber bands" that are in an upright vacuum cleaner. </p>

<p>Yesterday I had the ultimate horror of an adapter ring and circular polarizer stuck together. Think about this - the adapter ring is not connected to anything and offers little room to grab, and the CPL is even worse since it can spin around except for a super-narrow edge.<br /> <br /> Latex medical gloves gave me way more grip with less force, which is what got them apart.<br /> <br /> Oh, and I stuck them in the freezer for a bit. Diff. metal alloys will expand/contract at diff. rates, so this can help. The problem is guessing which piece is expanding or contracting more - if it is the reverse case, you actually need to heat them up, not cool them down. No way to actually know offhand which case you have unless they got stuck AFTER a big temp change, so you can make an educated guess as to what happened.</p>

<p>I just had the same problem with a circular polarizer - tried the rubber band, rubber surface, etc. No luck. What DID work was PAPER MASKING TAPE. Wrapped a piece around the whole of the polarizer circumference and turned it slowly. Bingo.</p>

<p>Electrical tape around the outer rim tied the moving circular polarizing element to the ring grooves around the filter edge worked for me.</p>