Lens Nightmare, Please Help

[Julian Mole]

Hi,

I am feeling a bit sick at present; as I got caught in a torrential rainstorm this afternoon and my 1 month old Canon 400mm f/5.6 lens' objective got splattered with muddy water and grit, despite my covering both camera and lens with a Optech Rain Sleeve.

(This was my inadvertently own fault; as I neglected to take the lens cap with me when I left and I also didn't close the front opening of the cover until it was too late! )

However I know enough about optics to have left the dirt alone, but I am now wondering what the best course of action is?
I am usually nervous enough about cleaning optics which have got grubby from careful use (dust, dew etc.) so you can probably imagine how little I fancy tackling grit and mud!!

Would sending it to an optics cleaning specialist, perhaps Canon UK, be advisable?

Please let know your thoughts, and possibly share any similar experiences.

Thanks,

Julian.

[Alfred Forns]

Should be easy to clean Julian !! No need to worry.

Need a fluid to remove the mud, don't scrape once it dries. I use a solution called Lens Clens for normal cleaning. Would buy any lens cleaning solution and sterile cotton. Wipe cotton and slowly clean mud and keep replacing the cotton.

I don't like the microfiver cloths for this type cleaning since its easy to scratch the lens surface.

btw once your lens is clean all it takes to clean again is the cotton ball with a drop of liquid then start rubbing at the center in little circles moving out. btw do blow the dust before starting the cleaning.

[Axel Hildebrandt]

This lens is quite sturdy, don't worry too much. Al gave you good advice, just make sure to remove all sand/mud very carefully before cleaning it more thoroughly.

[James Shadle]

You might want to blow as much of the sand/dirt off as possible before you begin the wet cleaning.

[Julian Mole]

Hello Alfred, Axel and James,

Thank you for the helpful advice. And thank you for giving me the confidence to try cleaning the lens myself (things didn't seem quite so bad after a decent night's sleep!).

I already had some cleaning solution and sterile cotton wipes, which I'd bought for cleaning my astronomical telescope and eyepieces, so with great patience I gently dabbed all the grit particles off, the only tricky bit was a large gritty blob positioned at the join between lens and lens cell.

I must have used 60 or more wipes to clean the whole lens, and sweequed the rocket air blower hundreds of times!!

Anyway it went well, and now all the lens needs is a bit more buffing to get rid of the drying marks left by the cleaning fluid. I have try removing these by breathing on the lens and gently wiping, but the results with the cotton wipes were patchy so I gave up. Would a microfibre or silk cleaning cloth be better for this task?


Yours, feeling happier with life,

Julian.

[Axel Hildebrandt]

I'm glad you were able to clean it yourself. As for the remaining drying marks, I sometimes use mild dish soap if necessary. If it is just a little, I would breathe on the lens and use soft cotton to wipe it.

[Roger Clark]

Would buy any lens cleaning solution and sterile cotton. Wipe cotton and slowly clean mud and keep replacing the cotton.

I don't like the microfiver cloths for this type cleaning since its easy to scratch the lens surface.

I already had some cleaning solution and sterile cotton wipes, which I'd bought for cleaning my astronomical telescope and eyepieces, so with great patience I gently dabbed all the grit particles off, the only tricky bit was a large gritty blob positioned at the join between lens and lens cell.

I must have used 60 or more wipes to clean the whole lens, and sweequed the rocket air blower hundreds of times!!

Anyway it went well, and now all the lens needs is a bit more buffing to get rid of the drying marks left by the cleaning fluid. I have try removing these by breathing on the lens and gently wiping, but the results with the cotton wipes were patchy so I gave up. Would a microfibre or silk cleaning cloth be better for this task?

All,
A STRONG WARNING: Cotton scratches optical surfaces. Cotton should never be wiped across any optical surface. And when there is dust, you should never do any wiping action of any sort with any applicator as you
could loosen the dust and drag it across the optical surface, scratching it. Use dabbing motions or rolling motions with cotton swabs, so the cotton is never wiped across the surface. There is a collodion that can be used to clean optics (google "collodion optical cleaner" and you'll get many hits.

Microfiber optical cloths are much safer for cleaning optics than any cotton. But wiping by any material can drag dust and scratch optics. One thing that does work well for stubborn grease is a little mild soap, water and your fingers. Your fingers are very sensitive to the feel of a dust spec and you can instantly stop any motion if you feel dust/dirt specs. This works best if you can remove the optical element from the cell and then you can also put it under a stream of water. I've used this method on front surface astronomical mirrors for decades with great success.

Roger

[Julian Mole]

Hi Roger,

Thank you for the warning, however I've realised that I gave duff information - as they were actually synthetic cotton wipes!

I followed the cleaning method detailed here: http://www.arksky.org/asoclean.htm


PS. When I have time and energy enough, I'll have to have a go at my 80mm refractor's objective lens, as I've been putting it off for ages! :-)

[Alfred Forns]

Roger I guess I use what works for me. Have been using that method for more years that I can remember on all my lenses ... both 500 and 600. To date no one single problem. Roger if cotton scratches the lens surface how come I don't have a single scratch in fifteen to twenty years of using the method?

Perhaps the best way would be to clean the lens according to the manufacturers recommendation ... and I'm not sure what that is.

Roger will try one of those microfiver cloths on an old lens an see results. btw would you use the cloth along with LensClens or just the cloth alone. Always open to suggestions and they are much appreciated !! Thanks !!!

[John Chardine]

I still have a small, red microfibre cloth given to me by a passenger on a ship in Antarctica in 1995. It's as good as the day he gave it to me, and I just wash it in mild soap every now and then and hang up to dry. For stubborn marks I will use the cloth with a little bit of Kodak lens cleaning fluid. I feel your pain Julian having mud on a lens! Well done for persevering.

[Roger Clark]

For anyone wanting to experiment with methods for cleaning, I suggest the following experiment.

Purchase a small piece of clear plexiglass from a hardware store. Get some cotton swabs, your favorite cleaning solution and a microfiber cloth and/or other things you use. Clean the plexiglass with your favorite method, then look at the plexiglass held up to a bright light. Can you see any haze? If so that is due to fine scratches. If not, you did a good job. Try with different methods.

In my experience, cotton if drug across the optical surface will produce fine scratches. If you use the cotton swabs only in a dabbing or rolling action and never drag the cotton across the surface you shouldn't produce any scratches. But sometimes some dirt or grease will not come off easily and more action than dabbing is necessary. Try the same thing with microfiber cloths. It is harder to scratch the surface with microfiber cloths, but of course if you press hard enough you can scratch an optical surface with anything. Plexiglass is a good test material because it is soft and you aren't actually damaging an optical surface.

Roger

[John Chardine]

Good info from all. As an amateur motor mechanic I often use the principle that softer materials can't deform or mark harder ones. I can hit a piece of steel with a piece of brass all day and the brass (softer) will show the marks, not the steel. Same principle applies to lens cleaning with the reminder that your cleaning implement is touching relatively soft (I assume) lens coatings, not the harder glass lens itself.

[William Malacarne]

It has been my understanding that GOOD coatings are very hard....such as used on the top of the line Hoya, B+W etc.

Bill

[Juha Hytönen]

Purchase a small piece of clear plexiglass from a hardware store. Get some cotton swabs, your favorite cleaning solution and a microfiber cloth and/or other things you use. Clean the plexiglass with your favorite method, then look at the plexiglass held up to a bright light. Can you see any haze? If so that is due to fine scratches. If not, you did a good job. Try with different methods.

Roger

Instead of the plexiglass you can just use the cd rom disc (unused). Do the above mentioned test on cd's surface and try to look fine scratch marks using bright light.

[John Chardine]

It has been my understanding that GOOD coatings are very hard....such as used on the top of the line Hoya, B+W etc.

Bill

That would be nice to confirm Bill.

[William Malacarne]

I have found that yes they are hard....In the mid 60's Leica had some problems with the bonding of the coatings to the glass but it was not in itself the coating. There are test kits you can buy to check the hardness of the coatings on optical; glass, but they seemed to start at $300 for a decent one.

I fond the following stated on 2Filter.com.
The new Digital High Grade, SMC and MrC coatings have anti-scratch top coats to extend the life of the coatings, but still be careful, Any filter Multicoating are worth the extra effort in cleaning and care, the results can be seen on your images.


Bill
I will continue to look more as time permits.....would also like others opinions on this.

[Roger Clark]

Instead of the plexiglass you can just use the cd rom disc (unused). Do the above mentioned test on cd's surface and try to look fine scratch marks using bright light.

Yes, I suppose so, but it would be less sensitive that a transmission test through clear plastic. The scattering fro the CD would add confusion in the CD test.

Roger

[Mack Hicks]

Besides my camera gear, I use a lot of expensive optics at work, operating telescopes and an operating microscope. I share a treatment room with an opthalmologist who is also a photographer. His life is optics. He always has a microfiber cloth in his pocket. I do not use cotton except to blot and roll with a wet swab, usually use a lens cleaning solution that is also an antifog but it is mostly alcohol. Blow off the loose stuff, then use wet, wet swabs and microfiber to dry things and buff. My $0.02 but wet is best.

[Julian Mole]

Thanks for the input, Mack.

Julian.

[Julian Mole]

I followed the cleaning method detailed here: http://www.arksky.org/asoclean.htm

As I posted the link above, I feel responsible to warn anyone from using Kleenex tissues as part of the method described. DO NOT use Kleenex tissues to clean your lens, I sadly speak from personal experience!!

Originally when I linked this, I had followed the instructions provided by Oceanside Photo and Telescope ( http://www.optcorp.com/ ), from whom I purchased the Arkansas Sky Observatory (ASO) cleaning kit, these instructions are very similar but describe using the lint free wipes throughout the cleaning process.
However this weekend when I needed to clean my lens again to remove some dried water marks, I decided to follow the ASO instructions (the page linked in the quote) and I ended up with small scratches to the lens coatings after I'd gently drawn the Kleenex over it.

Sadly looking back I should have thought about what the tissue is made of: wood pulp!! But, I had hoped the absorbency of the tissue would work better for wiping up the cleaning solution and so, unfortunately, I put my faith in what I thought was a tried and tested method - using sound materials! :-(

Hopefully these very small marks on the coatings will not show up in any of my photos, but this was a painful lesson to learn, and I would hate for anyone else to cause similar damage to their lens by thinking Kleenex were safe to use.


Always learning the hard way!

Julian.

[Roger Clark]

Yes, tissues will likely scratch more than cotton. The best thing I know of these days is micro-fiber cloths made for optical surfaces. But with enough pressure anything will scratch.

I use two things on my optics: micro fiber cloths and my fingers. The problem with use of any cloth is that if you hit a dust spec, you don't feel it and you drag it across the surface scratching it. With your finger, you can feel the irregularity and stop before much damage is done. I do have 30+ years of experience doing this and have also used my fingers for spot polishing optics (I have ground and figured my own optical surfaces when I was younger and had more time). To use you finger, one must wash it well first and use a wetting agent. Whatever you use, a light touch is critical.

Roger