# Visible Dust inside Canon EF135mm f/2L - please is there any Help? Disassemble?



## ZoeEnPhos (Oct 30, 2012)

Dear Co-Canon-Lens-Users!

Anyone here having the experience of *Dust particles or a some kind of visible "mark" inside the lenses* and between the most rear lens element pointing into the camera (not in the front elements) of *Canon EF 135 f/2L*

I would very much appreciate your advice, if someone have cared to maybe try to "open up" or disassemble yourself a lens in order to remove internal dust particles from a EF135mm f/2L without IS?

1. Is this "over-kill" to do?
2. Will Canon accept to remove this from a "L"-lens that should be dust-resistant?
3. Could this operation to take apart an new Canon factory "put-together" lens even have the risk of making the whole lens out of center or even worse the dust-problem?
4. Is Canon granting a free dust-removal to a brand-new lens that is less than a year old since purchased?
5. the dust or some kind of visible "mark" is between the most rear glass and the next one as far as I can see when I look through the open lens against light from window - could I somehow "open" this lens myself or is it maybe jeopardize the integrity of this lens altogether?

To me it is a bit a disappointment to find this dust/mark quite late after purchase in April 2012 this year and I am in doubt of getting any real help!

What is your most wise advice - if you yourself were into this dust/visible mark inside a fast glass like this and the dust/visible mark is in REAR of the lens barrel=?

Thank you for your valued thoughts/advice!

Wishing you all the Best and of course may you have NO dust in your primes!

/Charl


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## 2n10 (Oct 30, 2012)

Is the dust in any way affecting your photos?

Most lenses have dust internally from the manufacturing process.

1 IMO yes
2 Canon will be happy to clean it for you for a price.
3 yes
4 I doubt it
5 yes


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## symmar22 (Oct 30, 2012)

You should define more precisely what's inside your lens. 
In case it's dust, just leave it, a I am not sure how much the 135mm f2 is weather sealed, but at some point every lens gets some dust inside, it's just life. The good side of it is that it has NO effect whatsoever on the IQ.

1-IMO it's just plain overkill to have it cleaned, or even checked in this case.
2- Yes they will be glad to take a lot of money from you.
3- If you open a perfectly good lens, you take the risk of a not so perfect reassembly.
4- I would be very surprised that dust is covered in the warranty of a lens
5-Never disassemble it on your own, you will just kill it (unless you have a real experience in lens repair)

The only thing that worries me is that you do not seem very sure about what is actually inside your lens. If it's dust, then just leave it. If it's something else, then it may be a good idea to have it at least identified.


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## jdramirez (Oct 30, 2012)

I haven't heard of dust being a factor in primes. I have heard about it in zooms where air comes in and out. For the most part, I'm a little OCD about my lenses so I wouldn't want dust in their either, but it really shouldn't affect picture quality.


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## RLPhoto (Oct 30, 2012)

If the Dust is visible in your photos, Send it to be repaired.

If not, Then don't worry about it. 

If you worry about it, Send it in.


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## Octavian (Oct 30, 2012)

Lenses Breath... On a prime when you change focus the inside elements move there needs to be breathability same on the zooms lenses are never completely sealed... are they? correct me if im wrong?
lol i.e. look at a 50mm 1.4 or a 100-400! gaping channels around the rear element and the whole barrel of the 100-400 moves like a pump action shot gun!


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## emag (Oct 30, 2012)

In a previous I made a living working on optics. A little internal dust is not worth worrying about. A small chip or scratch is not worth worrying about (a dab of flat black paint on a chip is an acceptable treatment). A lot of internal dust is not really worth worrying about, you'd be surprised how much dust it takes to have any effect on images. A fingerprint IS worth worrying about, never allow a fingerprint to remain on a lens. I keep a bottle of ROR and some cotton swabs on hand at all times for just that reason. Dust on the sensor IS worth worrying about - have it cleaned, better yet, get comfortable doing it yourself. Internal fungus is worth worrying about - have it cleaned. Go out and use your lens.


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## Mt Spokane Photography (Oct 30, 2012)

Unless you know what you are doing and have the right tools (JIS Screwdrivers for one), you will likely cause more issues than you cure by disassembling a lens.
Dust is almost never a issue, but Canon will clean it for you.


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## Halfrack (Oct 30, 2012)

http://www.lensrentals.com/blog/2011/08/the-apocalypse-of-lens-dust

Kinda crazy how 'big' a speck of dust has to be...


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## ZoeEnPhos (Oct 30, 2012)

emag said:


> In a previous I made a living working on optics. A little internal dust is not worth worrying about. A small chip or scratch is not worth worrying about (a dab of flat black paint on a chip is an acceptable treatment). A lot of internal dust is not really worth worrying about, you'd be surprised how much dust it takes to have any effect on images. A fingerprint IS worth worrying about, never allow a fingerprint to remain on a lens. I keep a bottle of ROR and some cotton swabs on hand at all times for just that reason. Dust on the sensor IS worth worrying about - have it cleaned, better yet, get comfortable doing it yourself. Internal fungus is worth worrying about - have it cleaned. Go out and use your lens.



Dear sir (emag)
Thank you so very much for your given facts to me!
I would be quite sure that it is NOT fungus - and there are kind of dust yes but this is like a scratch on the surface more or less what I first tried to gently swab away with a new and clean LensPen and also tried a brand new and clear lenspaper from Kodak but it clearly was INSIDE the and between the two most rear lens-elements. 
The good news is that it does not affect the picture as far as I have seen - and also - the fact that I seldom or never use this Canon EF 135mm f/2L stopped down more than about f/5.6 - because one reason to purchase in this type of fast prime is to use it wide open or maybe at f/2.8 - if I need more DOF I usually change to EF 100mm f/2.8L IS USM.
I also checked my EF300mm f/2.8L IS USM that I purchased as brand new and I have been extremely cautious in the process of change of lenses/extenders with this lens and I could not see one single dust particle inside internally in this lens and when I checked my EF 135 f/2L I was quite surprised to find dust in a quality built "L"-lens , that to my understanding maybe should have some kind of dust prevention in the construction/sealings=?

Anyhow *I do appreciate your answer as well as all your others answers* to my kind of novice level question - but I am quite relieved by all your answers and no I think I wish not to give my money to Canon for some small fraction of "scratch" on the surface of the coating and some additional dust particles inside this fast lens!
Thank you so very much for your contributions to my first question here on this knowledge-treasure-forum - because of ALL of YOU!

Wishing you all excellent shoots with your also excellent lenses and DSLRs and much fun and joy when enjoying the IQ and results of your photographing!

//All the Best! 
///Charl


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