Dealing with stuck filters

[Ramsden]

Hi folks 

EOS90D and 7, about to be 8 lenses. Recent posts have revealed how common the problem of stuck filters is amongst us. I got mine down to two, but they were STUCK! 

As an engineer I genuinely apologies for this photo of the method I resorted too, to remove the stuck filters. But I was extremely careful, and eventually got them off my lenses. I have to tell you, that even with these plumbers grips, it was difficult. 

Lenses are all now cleaned and in good condition, awaiting new clear glass filters and maybe a trial with magnetic filters. All options remain open, but I've just fitted a new (expensive) clear 67mm filter, and its 'clear'! How on earth do you assess clear glass?

 Ramsden 

[Ramsden]

Good morning 

I tend to like this idea, and agree with Zak. I don't like the idea of any substances being near my camera mechanism. It just doesn't feel right. 

The camera feels like a 'dry' mechanism and works well, down to excellent engineering.

Ramsden 

[Ramsden]

One further thing, if you examine a lens filter after it has been stuck, it appears to have a grey substance on the threads.

I wonder if this is the result of electrolysis, when an electronic current passes between dissimilar metals, and the weaker metal corrodes. On bigger structures the engineers use cathodic protection to manage this process.

Given that my filters, up till now, have been cheap uv's, that would make sense.

Just a thought...

Ramsden 

[SignifDigits]

@Ramsden as an engineer I'm sure you are ware that what you experienced was bimetallic bonding due to galvanic action or oxidation.  If the lens threads are brass, then brass would be the right choice.  If aluminum, then aluminum.  As many moden lenses use aluminum, brass threads is a great marketing ploy but a bad choice as there is natural galvanic action between aluminum and brass due to humidity in the air.  Brass was perfect when lens threads were brass, but not so with aluminum.

From the AI:  "Brass and aluminum cause galvanic corrosion when in direct contact, with aluminum acting as the sacrificial anode. In the presence of an electrolyte (like moisture or water), electrons transfer between the metals, causing the aluminum to rapidly dissolve and physically fuse to the brass."

Of course aluminum DOES oxidate (aka rust), just creating layer of aluminum oxide instead of the iron oxide rust that we all know of as "rust".  

I'm assuming what you saw was aluminum oxide as it is grey (often spelled gray across the pond).

If we put anything on the threads it should be a corrosion inhibitor.  None of the materials mentioned thus far qualify.  CRC (and others, even the company that makes WD-40) make products designed for this purpose. 

Paint (hopefully anodized) on both threads is the best protection if both are aluminum.  Anodization is preferred over regular paint as it is more permanently bonded.  I'm assuming that Canon and the better filter manufacturers use anodization.

I notice that several of my Canon lens threads are plastic.  This is perfect.  It may seem cheap, but the threads on my RF 70-200 f/2.8 L USM Z lens appears to be plastic and I don't think anyone would call that a "cheap" lens.  The most recent EF version of this lens was of aluminum.  If your lens threads are plastic you don't need to apply anything as aluminum oxide does not adhere well enough to plastic to cause concern.

The only time I would consider a treatment would be if I were using brass to aluminum (lens to filter) or vice-versa or if both the same materials if they were going to be on "forever-ish" and/or in a harsh environment.

Of course, anytime your lens threads get wet, you should take the filter off to let them dry.  And anytime you install a filter it would be wise to inspect them for signs of degradation of the coating on the threads.

I take my lens filters off for more serious shooting, and that seems to work for me with no treatments.  If I were leaving one on "forever" kind of thing I would attempt a layer of teflon tape as superior to a coating.  That said, getting that in place would be a nightmare, so I really cannot recommend it (I gave an attempt whilst writing this and wholly do NOT recommend it as practical, just technically superior) as a real-world solution.

Thus, what I do and personally recommend is putting a filter for transport, etc, and taking the filter off and counting on the lens hood to protect your lens during use. I install high-quality clear lenses for those times I forget or want to keep, something off the lens (as when I'm in a mist at the bottom of the waterfall when take the filer off and on)  If I use a CPL (and I have not yet) I would only install it during shooting.  And when things are wet, bet sure to take the filter off so that it's not trapped in the threads.

That is a cool looking tool, by the way.    I might have some tool envy 🙂

[Ramsden]

Hi 

Thanks for a great response to my message and some great takeaways. You made me laugh with the Teflon tape. I, like 000s of other folks have probably ended up in the same mess doing some home plumbing. And - it was on my list of things to try on the filters - but I'll pass on that one  now.

But from what you wrote, I was on the right track,  particularly with dissimilar metals. 

In the 1970s I worked on the North Sea gas pipelines  covering a couple of thousand miles. We used to weld a small boxes with 'soft' metal inside onto the pipeline, every few miles. The box was earthed by a cable, and I'm sure a small electric current ran through the pipeline so it acted as a sacrificial anode. 

But what I really like is your idea of just using filters for transportation and take them off when shooting. Now thats the most logical and (with hindsight) sensible thing to do. Since last week, I've ordered 3 B&W clear filters- at great expense. But your idea has stopped me buying anymore, in fact they might get returned!

I'm not particularly fanatical about my photographic work, but I lean towards letting the camera do most of the work, as sitting in front of a computer doesn't appeal to me.

Thanks again 

Ramsden 

[ebiggs1]

"... I really like is your idea of just using filters for transportation and take them off when shooting."

I don't and I don't do that. Terrible idea. B+W brass filters almost, to never, stick on a lens. They just don't. And, I almost, to never, remove one for shooting. I can't remember the last time I removed one for shooting. Think about it, your lens is in its most safe state when it is in the bag for transporting. It is in its most vulnerable state when using it. So, where does it make sense to use one?

Personally, I almost always have and use a lens hood. But a hood only protects so far. It does not protect from dust or sand or water, etc. It also doesn't protect form a 3 year old that thinks that dark hole is a good place to squirt the ketchup bottle. Yeah, that was one wedding reception I did. You never know the danger until after it happens.

You just spent a wheel barrel full of money on a  new 16-35mm zoom it deserves a top quality B+W protecto filter for right out of the box.  It's better to clean a replaceable filter than the front element of expensive lenses.  But it's your dime and your choice.

[ebiggs1]

I've had the unfortunate situation of trying to remove stuck filters when I did my DSLR 101 classes. I never got those plastic gadgets to work. However, with all the recommended methods out there the one that works is the best. I don't think anyone of them is the 100% answer all the time. Different methods work at different times.

[Ramsden]

Hi EB 

I totally agree and I'll get one ordered now. They aren't cheap, but your policy is right on the money. I've bought 3 B&W clear filters in the last couple of weeks. They are beautifully engineered, somehow just ooz quality. 

Thanks for the heads up - £££s taking a hit this month, but quality equipment needs looking after.

Loved the ketchup story!

Ramsden 

[SignifDigits]

It's a very good idea to take your filters off prior to shooting if you want the very best optical performance (unless you're using a specific filter for optical effect, of course) from your lens. A lens was scientifically designed by the optical engineers to be used without an any additional optical element (aka filter).  Why would you spend your hard-earned dollars on a highly engineered lens then willingly introduce another optical element in that optical train?  

Another layer or glass invites aberrations, not matter how good the filter is.  I, and several others on this site who made this point to me in previous posts, follow the practice of taking the filter off prior to shooting.  But to each their own.  It's not a "terrible idea", just a matter of personal priorities and preference.  This method has also always and forever prevented a stuck filter for me - never had one and am guessing I never will.  

Also, if the shooter allows an object to break a filter while mounted that sends shards of glass headed to the front element of the lens.  Not great.  Of course the front element of the lens can have a considerable amount of small scratches without significant optical effect but if you tear the coating, then not so much.  As it turns out the front element of most lenses is practically indestructible.  But certainly best to not test that theory.

The reason any filter doesn't stick on is because of the coatings (usually anodized paint).  As long as the threads are coating to coating it shouldn't stick.  Metal to metal is where things go bad.  Aluminum to aluminum is bad, brass to aluminum is even worse.  If you're gonna leave them on forever you will need to either take them off and check that the moisture and accumulated gunk in the threads hasn't cause a breach in the coatings any time you encounter moisture and gunk, clean them and dry them and make sure they stay clean.  If you don't it's best to have nice tools and multiple techniques to get them unstuck in case that happens.

I have safety systems (sling plus wrist strap) to prevent droppage and can't recall ever sticking my lenses into places where they are likely to be truly damaged.   Perhaps others do, though.  Carrying cleaning kit and blower for dust, sand and water is a must for either lens or filter.

Shoot the way you want to shoot, though, and I will do the same.    I got my "terrible idea" from some really good shooters based upon their inputs on optical risk vs. physical risk and I consider my risk of physical damage negligible compared to the risk or the filter causing unwanted optical aberrations.  I still buy the best clear filters from B&W and others in that league that money can buy, as I am not perfect and forget and shoot with the filter on sometimes and I would prefer that it have the best optical characteristics when that happens.

I don't say our (mine and the other better shooters than me that let me this direction) way is the "right way" to do things, but it's not a "terrible idea" nor "wrong" either.  You're aware more than I am that this topic has been discussed previously without everyone in agreement with either approach.  This  is where I and a number of others feel most comfortable shooting.

I will attempt to be more even-handed in my recommendations in the future regarding taking the filter off for shooting and explaining the pros and cons of both "camps", as just because I'm in this "camp" now, doesn't mean I didn't come from the previous one (I did).  It's not an emotional issue for me though and I don't think either approach is a "terrible idea".  Each shooter should do what they feel best fits their priorities.

[Ramsden]

Hi 

Thanks for your message. I've found this thread quite fascinating, and my natural instinct with most things is to keep it simple. I certainly lean into the straight out of the camera school and your point about the optical engineers strikes home. Plus, a B&W 82mm clear is over a £100 in the UK. That's serious money for clear glass. 

I guess with a good hood and cap, plus being very careful,  my lens will last a long time.

I've probably waisted some money on my photographic journey, but I've got a great camera, a few nice lenses and a hobby that I really enjoy and provides challenges in all shapes and sizes.

Best

Ramsden 

[SignifDigits]

Don't get me wrong, as I said I DO put a top-dollar filter on my lenses, as I'm forgetful, get in a hurry and shoot with the filter (almost said "cover" by mistake.  Sadly that's true too - or at least it comes up to my eye before I remember!) on sometimes.  I just prefer shooting with the filter off.   And if you're just looking for protection when not shooting, and not as impatient nor forgetful as me, a less expensive filter or lens cover serves that purpose.