24-70 f/2.8 L II front coating peeling off?

[traveller]

I have a friend whose 24-70 f/2.8 L II is currently with Canon, as the front coating appears to be separating from the glass of the front element. Has anyone else experienced anything like this with any of their lenses and if so, how did Canon respond?

 

[Marsu42]

I have a friend whose 24-70 f/2.8 L II is currently with Canon, as the front coating appears to be separating from the glass of the front element. Has anyone else experienced anything like this with any of their lenses and if so, how did Canon respond?

Not if *that* would happen with Tamron, what would the community say (remembering the s***storm over the Internet after a front element in one 24-70vc dropped off...). With Canon, I guess it's an hearsay isolated example of product failure, probably due to doubful user handling, that is to be expected with mass production and just has to be replaced under warranty :->

 

[Loswr]

It's certaily possible for the coatings to become damaged or to delaminate. If the outer protective layer(s) are damaged (by physical impact like an object hitting the front element or a scratch caused by larger particulates on the lens when it's rubbed with a cleaming cloth), moisture can penetrate the layers of coatings, and some of the antireflective layers are quite susceptible to moisture damage (not even water on the lens - humidity is enough). Use of inappropraite cleaning solution can damage coatings, even Scotch tape can cause microscopic lesions of the surface.

remembering the s***storm over the Internet after a front element in one 24-70vc dropped off...

It wasn't just one (and it was the second element), and Roger provided a good reason for its occurrence.

http://www.lensrentals.com/blog/2012/09/tamron-24-70-f2-8-vc-issue

Incidentally, he praised Tamron's handling of the issue.

 

[Don Haines]

I have a friend whose 24-70 f/2.8 L II is currently with Canon, as the front coating appears to be separating from the glass of the front element. Has anyone else experienced anything like this with any of their lenses and if so, how did Canon respond?

Many years ago I had that problem with a lens and the coatings disintegrated.. It was a 50F1.8 so it was not even worth the cost of shiping it to be looked at... The camera had been outside all day at -65C and when it warmed up the coatings fell apart. I think it was due to the severe cold.... Did your lens get excessively cold?

 

[traveller]

It's certaily possible for the coatings to become damaged or to delaminate. If the outer protective layer(s) are damaged (by physical impact like an object hitting the front element or a scratch caused by larger particulates on the lens when it's rubbed with a cleaming cloth), moisture can penetrate the layers of coatings, and some of the antireflective layers are quite susceptible to moisture damage (not even water on the lens - humidity is enough). Use of inappropraite cleaning solution can damage coatings, even Scotch tape can cause microscopic lesions of the surface.

Possible explanation, but it was quite widespread over the front element (sorry, I didn't think to take a photo at the time). At first, I thought it was just moisture, but it wouldn't rub off; it also didn't look like your usual scratches: they weren't thin lines, but fat and speckled. It's strange because it's his newest lens (less than a year old) and none of the others are in this sort of state, despite similar usage.

UPDATE: I've just had a 'phone call from him (whilst typing this); Canon are blaming this on "excessive cleaning". The lens is just over 12 months old and apparently been cleaned with only a microfibre lens cloth... Time to buy UV filters for my lenses? Oh rats, the good ones are multi-coated too!!!

 

[privatebydesign]

I have a 100L Macro which I believe has the same nano coating, not long after I got it I noticed a "blemish" in the coating, it wasn't there when I got the lens. I tried to rub it off but it wouldn't budge, indeed it looked like a pocket of air, or bubble in the coating, certainly it looked to have the third dimension or depth to the blemish. I was disappointed but was determined to either clean it off or get a new front element. With that attitude I set about really laying into "cleaning" it, basically I rubbed the sh-t out of it and did nothing but make many rub marks around the blemish. I was resigned to a new element. However before I sent it off I had my cleaning fluid out and tried one last time, voila, not only did the blemish disappear completely but also the "cleaning" marks all went as well.

Now I recount this not to make myself look like the dufus I was, but to point out that even when we are "certain" the coating is damaged, it might well not be, and further, I find it practically impossible to believe you could rub those nano coatings hard enough by hand to damage them, I know how stupidly hard I "cleaned" mine with zero ill effects.

 

[tron]

I have a 100L Macro which I believe has the same nano coating, not long after I got it I noticed a "blemish" in the coating, it wasn't there when I got the lens. I tried to rub it off but it wouldn't budge, indeed it looked like a pocket of air, or bubble in the coating, certainly it looked to have the third dimension or depth to the blemish. I was disappointed but was determined to either clean it off or get a new front element. With that attitude I set about really laying into "cleaning" it, basically I rubbed the sh-t out of it and did nothing but make many rub marks around the blemish. I was resigned to a new element. However before I sent it off I had my cleaning fluid out and tried one last time, voila, not only did the blemish disappear completely but also the "cleaning" marks all went as well.

Now I recount this not to make myself look like the dufus I was, but to point out that even when we are "certain" the coating is damaged, it might well not be, and further, I find it practically impossible to believe you could rub those nano coatings hard enough by hand to damage them, I know how stupidly hard I "cleaned" mine with zero ill effects.

Thanks for the info. This is reassuring. I remember my EF 14mm f/2.8L II which had (or has I am not 100% sure right now) a softness that could not be removed. Anyway it turned out that although it could not be removed it could be ... moved! So it looks like a similar case

 

[TexPhoto]

Some photos of what is happening would certainly help.

 

[Mt Spokane Photography]

I have a friend whose 24-70 f/2.8 L II is currently with Canon, as the front coating appears to be separating from the glass of the front element. Has anyone else experienced anything like this with any of their lenses and if so, how did Canon respond?

Are you saying that the nano coating on the glass is pealing? The process of applying the nano coating is pretty high tech, Is it possible that he used some sort of solvent to clean it?

http://www.canon.com/technology/s_labo/light/003/03.html

 

[JustMeOregon]

Of course I have no idea if it's related, but I recently accidentally destroyed a pair of eyeglasses by washing them with 99% isopropyl alcohol. They peeled like 30-year paint on the sunny-side of a barn...

 

[Mt Spokane Photography]

Of course I have no idea if it's related, but I recently accidentally destroyed a pair of eyeglasses by washing them with 99% isopropyl alcohol. They peeled like 30-year paint on the sunny-side of a barn...

Yes, its common on eyeglasses, they are usually plastic, so the coating is not flame sprayed (Vapor Deposited) at extreme high temperatures like glass camera lenses. That process costs more than a high end pair of glasses, and has been extremely reliable, so its unusual to have this happen. There can be manufacturing defects, or issues using the wrong cleaner.

 

[traveller]

UPDATE: I've just heard back from my friend, the technician at the service centre told him that it is very unusual for the lens coating to peel in this way after such a sort period of time. Usually they would expect to see signs of very heavy usage on the body of the lens in these cases. The service centre have been instructed to replace the front element under warranty and send the damaged front element back to Canon for further investigation. Meanwhile it looks like my friend will have his repaired lens back tomorrow.
I'd say this might be a case of an isolated manufacturing defect. I don't think it's anything to worry about if you own this lens, but worth knowing in case it does happen to you.

 

[tron]

Thanks for the warning. I always use filters so normally I do not watch what happens between the filter and the lens but I will give a look every few months.

 

[Mt Spokane Photography]

UPDATE: I've just heard back from my friend, the technician at the service centre told him that it is very unusual for the lens coating to peel in this way after such a sort period of time. Usually they would expect to see signs of very heavy usage on the body of the lens in these cases. The service centre have been instructed to replace the front element under warranty and send the damaged front element back to Canon for further investigation. Meanwhile it looks like my friend will have his repaired lens back tomorrow.
I'd say this might be a case of an isolated manufacturing defect. I don't think it's anything to worry about if you own this lens, but worth knowing in case it does happen to you.

They do a large batch of them at once. It is a very critical process, but its hard to understand why it would not affect a whole production run, or at least a whole tray of them, unless someone happened to somehow get just one lens dirty, or the cleaning process missed one lens.

You can get some info about the process here;

http://youtu.be/qzpt49qq6v4

 

[Don Haines]

UPDATE: I've just heard back from my friend, the technician at the service centre told him that it is very unusual for the lens coating to peel in this way after such a sort period of time. Usually they would expect to see signs of very heavy usage on the body of the lens in these cases. The service centre have been instructed to replace the front element under warranty and send the damaged front element back to Canon for further investigation. Meanwhile it looks like my friend will have his repaired lens back tomorrow.
I'd say this might be a case of an isolated manufacturing defect. I don't think it's anything to worry about if you own this lens, but worth knowing in case it does happen to you.

That is a good, responsible reaction from the manufacturer.... Shit happens, they can either learn from it or deny it... looks like they chose to learn.

 

[traveller]

UPDATE: I've just heard back from my friend, the technician at the service centre told him that it is very unusual for the lens coating to peel in this way after such a sort period of time. Usually they would expect to see signs of very heavy usage on the body of the lens in these cases. The service centre have been instructed to replace the front element under warranty and send the damaged front element back to Canon for further investigation. Meanwhile it looks like my friend will have his repaired lens back tomorrow.
I'd say this might be a case of an isolated manufacturing defect. I don't think it's anything to worry about if you own this lens, but worth knowing in case it does happen to you.

They do a large batch of them at once. It is a very critical process, but its hard to understand why it would not affect a whole production run, or at least a whole tray of them, unless someone happened to somehow get just one lens dirty, or the cleaning process missed one lens.

You can get some info about the process here;

http://youtu.be/qzpt49qq6v4

Even with the most thorough quality control, there is always variability which can mean that a defective unit slips through inspection. This is especially so when you are using statistical process control to ensure that correct standards are being achieved. This might be the case when there are a large number of units and it is uneconomic to inspect them all (although, as the video link clearly shows - Canon are claiming 100% sampling for lens element QC checks at the grinding stage), or when a particular check requires a unit to be destroyed (e.g. you wouldn't want to crash test every car you made!). This could possibly be the case (I'm speculating here) with lens coating resilience: you could test a statistically significant percentage, but if the testing process is damaging to the lens element or takes a long time (e.g. an accelerated ageing simulation), you couldn't test them all. Japanese companies tend to lead the way in process control and I'm sure that Canon has well developed procedures and tight tolerance limits for its processes, but even these cannot guarantee that no faulty unit will reach the customer. I'm guessing that given the opinion of the repair centre technician that it is not caused by misuse, is why Canon have expressed an interest in investigating the problem further: this is the sort of problem that technocratic Japanese managers like to deal with.

 

[traveller]

UPDATE: I've just heard back from my friend, the technician at the service centre told him that it is very unusual for the lens coating to peel in this way after such a sort period of time. Usually they would expect to see signs of very heavy usage on the body of the lens in these cases. The service centre have been instructed to replace the front element under warranty and send the damaged front element back to Canon for further investigation. Meanwhile it looks like my friend will have his repaired lens back tomorrow.
I'd say this might be a case of an isolated manufacturing defect. I don't think it's anything to worry about if you own this lens, but worth knowing in case it does happen to you.

That is a good, responsible reaction from the manufacturer.... S___ happens, they can either learn from it or deny it... looks like they chose to learn.

+1 -which is why I wanted to update the thread when I heard of the outcome: credit where credit is due.

 

[shhooter]

Seems i've run into the same issue with my 24-70L II (owned since October 2012). Noticed what looked like light scratches developing on the front element a few months ago but it was only visible in extreme off-angle lighting. Recently it's become much worse and clearly visible in normal light.

I've contacted CPS and will hopefully be sending the lens off this week. Glad to hear Canon replaced your friends under warranty, hopefully i'll have a similar result.

This is what my lens looks like:

 

[JustMeOregon]

Seems i've run into the same issue with my 24-70L II (owned since October 2012). Noticed what looked like light scratches developing on the front element a few months ago but it was only visible in extreme off-angle lighting. Recently it's become much worse and clearly visible in normal light.

I've contacted CPS and will hopefully be sending the lens off this week. Glad to hear Canon replaced your friends under warranty, hopefully i'll have a similar result.

This is what my lens looks like:

Of course after reading this I immediately dropped everything & painstakingly examined my 24-70 from every conceivable angle... Happily it checks-out just fine.

Its impossible to tell just from the picture, but the front element on your 24-70 kind'a looks like the coating may be wearing-away due to overly aggressive cleaning. Any chance that's the cause?

 

[shhooter]

Glad yours checks out okay.

Its impossible to tell just from the picture, but the front element on your 24-70 kind'a looks like the coating may be wearing-away due to overly aggressive cleaning. Any chance that's the cause?

That's what it looks like to me too. Funny thing is, this lens has never been dirty enough to get an extensive cleaning. I've never rubbed it with anything or used cleaning liquids. I usually use a rocket blower to blow away dust and occasionally hit it with a lens pen. Never had a problem with other lenses and similar treatment.

Hopefully Canon can tell me more this week.