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Thread: I need major help on a lens

  1. #1
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    Default I need major help on a lens

    I have been unable to clean the haze and crap off the outside of this lens, it is from a turret style cctv camera and i cant seem to get this crap off the outside lens, it has sadly been exposed to being in a shed for a while and i am out of any ideas if this optic can be saved, the rest of the system in the optic is fine, zoom iris and focus are all crisp and bright and the back side of this lens is fine as well, i dont know what the white crap in the one side is either, the aluminum housing for the lens is not corroded

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    Polk SDA SRS, Parasound HCA 3500, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

  2. #2
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  3. #3
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    Default

    I thought you were joking, but the links you provided documents a real condition.

  4. #4
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    Default

    Wd40 and wire wool
    Eat Sleep Lase Repeat

  5. #5
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    Default

    The lens may be etched from the fungus.

    Perhaps you can find a replacement lens here:

    http://www.surplusshed.com/

    Use the "lens finder."

  6. #6
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    Thank you for the help, i got it into a usable state now and some spots did etch, and the outer coating is now gone and one spot on the back of the lens but for cctv i think that would be find, but differently a learning experience

    i have seen this on dicro's , it made a spider like markings all over the thing, i had always wondered what caused it
    Last edited by Draco; 11-01-2015 at 12:49.
    Polk SDA SRS, Parasound HCA 3500, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

  7. #7
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    Whereas I've never heard of this before, I can think of a few possible solutions to assist with cleaning of my own given you have little to lose by trying them and can in any event check their safety with regards to the lens and coating on other websites. For a start, why not try soaking the lens in a warm strong solution of disinfectant as this is safe on most surfaces (check regarding lens coatings) and an efficient biocide. On vehicles which had green mould growing on them, I've seen traffic film remover be effective as a detergent although it can be harsh on some plastics as it can dry them out by stripping out some of the surface oils that maintain the plastics appearance and long term surface resistance to uv light, therefore use with caution in relation to plastic lenses. There are 2 simple methods I can think of that are preventative - the 1st is you could try a cctv lens heater as these are designed to prevent fogging through moisture and thus may assist here . Alternatively, you could put a dessicated sachet inside the lens housing periodically to keep the lens itself moisture free . These can be bought at camera shops. For the outside, I'd try a weekly clean with a disinfectant soaked cloth unless you can find something to indicate to the contrary that this may attack the lens coating, and then follow this after it has dried with a simple non abrasisive spectacle cleaner. As I said above the onus is on you to research the lens safety of these before trying as no responsibility is accepted for any damage. However they may give you some possibly viable ideas, subject to material suitability checks.

  8. #8
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    What is the diameter of the lens and do you know the power and refractive index??

    I can possibly make you a new lens but would really need to see the old one first before committing myself. We generally only manufacture plastic lens materials from 1.498 to 1.740 refractive index in our Lab. No problem coating it either, i'm assuming it would be a broadband reflection free coating?

    The reason i'd need to actually see the lens is to measure the Sag' of both surfaces so we produced something that was as close as possible to the original. If it had to be made of glass I could probably sort that for you although it may take a little longer.

    Cheers

    Jem

    P.S. Removal of coatings is usually done with a solution of either Hydrofluoric or Phosphoric Acid. Both of which are *really* nasty. Commercial products are available that are pretty weak, around 5%. Maybe ask at your local Optometrist/Optician/Eye Doctor, or whatever you call them on that side of the pond
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  9. #9
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    the lens is 62mm across and i dont have any other info except the lens is f 1-1.8 with a zoom of 11-110mm and is made from glass, i found out that sulfuric acid will damage the coating as well, the spot that had the worst fungi i lightly made a batch of acid, i dont remember the ratio, i too had thought it would take something much more powerful. i have about 2 hours time on a small buffer but the etching made the surface have a texture

    let me know the costs as this is a glass lens and the only element effected and i love this lens, it was originally a turret camera from a casino, the zoom is just amazing and all the controls are manual, the used external motors with feed back.

    please let me know the details
    Polk SDA SRS, Parasound HCA 3500, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

  10. #10
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    I did a test with the original CCTV camera, it is differently not as crisp as it used to be, I forgot to mention the main objective lens is rather thick and is slightly convex at the back,
    wif tearing my hair out would fix this i would, i have done amateur wildlife photography for a while and i had never have this happen, i had a very few lenses that needed the iris cleaned because of oil, it would make stopping down while taking a picture impossible i fixed it with toluene and to drive out and vapor or water as i discovered it fogged up but the solution was to put the lens in the oven as it was an all metal lens and could tolerate 120-150f, then just shut the oven off with the door closed to drive off the vapor inside and i did that in 1995 and it still works great, it was the original lens to my Minolta SRT 101 , if i ever get a really good camera i am torn between Sony(the evil empire that was once a slave too) and cannon, i like that when sony bought out Minolta they kept the same mount so in theory a used Minolta lens will fit there cameras
    Last edited by Draco; 11-02-2015 at 22:16.
    Polk SDA SRS, Parasound HCA 3500, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

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