**Read all about it Cloth dipped in warm water has removed the marks** Phew!
Hi guys
I was just cleaning the front element of my 70-200 ii in preparation for going to shoot tomorrow when I noticed a couple of distinct oval marks (rings). There are couple of very faint ones too. So I gave a rub with the lens cleaning cloth, thinking it might just be water splash residue from somewhere. It made no difference, so I got some lens cleaning fluid onto the cloth and tried again. Still there. It seems the marks might be on the inside, but its difficult to tell. If they are on the outside, no amount of cleaning will remove them, so is it a problem with the coating maybe?
Has anyone seen this before or have an idea what might have caused this? It makes no difference to the files, but if it gets worse, it probably will. I'm sure the marks weren't there a couple of weeks ago. The marks can be seen in the highlighted rectangle. Sorry for the link, but please click HERE to view. I did post this on another forum, but maybe someone here will have a few different thoughts
**edit**
I just did another shot HERE Its looking like a coating problem to me.
jcolwell wrote:
There's something going on there. Maybe you could take it to a camera repair shop or Canon service centre and ask them what they think about it.
Yeah, I could just leave it, but if it spreads (somehow) to other internal elements its going to get pretty funky and more expensive to fix. I've contacted my CPS rep in the mean time and I expect he'll tell me to send it in to a Repair Centre.
I was just cleaning the front element of my 70-200 ii in preparation for going to shoot tomorrow when I noticed a couple of distinct oval marks (rings). There are couple of very faint ones too. So I gave a rub with the lens cleaning cloth, thinking it might just be water splash residue from somewhere. It made no difference, so I got some lens cleaning fluid onto the cloth and tried again. Still there. It seems the marks might be on the inside, but its difficult to tell. If they are on the outside, no amount of cleaning will remove them, so is it a problem with the coating maybe?
Has anyone seen this before or have an idea what might have caused this? It makes no difference to the files, but if it gets worse, it probably will. I'm sure the marks weren't there a couple of weeks ago. The marks can be seen in the highlighted rectangle. Sorry for the link, but please click HERE to view. I did post this on another forum, but maybe someone here will have a few different thoughts
OK well definitely not a Newton's rings sort of thing. Very odd. I fear fungus is among us. Hard to be sure the from the photo. Don't know what else could do that to the inside element though. If it is on the outside it could be something gone wrong with coating.
skibum5 wrote:
OK well definitely not a Newton's rings sort of thing. Very odd. I fear fungus is among us. Hard to be sure the from the photo. Don't know what else could do that to the inside element though. If it is on the outside it could be something gone wrong with coating.
It doesn't look like any fungus growth examples I've seen from images I've seen online. I've just done a shot with an extension tube and bounce flash and then cropped it. This is looking like a coating issue to me. Thoughts? Link HERE
Once I had some heavily chlorinated water splash onto a front element; when it dried, it left similar circular/oval marks. It was VERY difficult to get it off (liquid cleaners and microfiber cloths didn't work), but eventually a lens pen managed it. I can't say the coating is damaged now but I wouldn't be surprised, because I used way more force than normal...
Good luck,
Jerry
RCicala wrote:
I agree it looks like a coating issue. If it's fungus it should fluoresce in UV light if you can get one.
Thanks The second image definitely looks like the coating is damaged. If its on the inside I'd love to know how that happened. It almost looks as if something acidic has eaten it away. I know you have literally hundreds of lenses there; have you seen this before at all?
It almost looks like something "splashed" onto the front element and it effected the lens coating. Try taking a photo of something dark and contrasty and see if anything shows as slightly different colour.
p.1 #10 · Strange marks on 70-200 II front element
Ed Brooks wrote:
It almost looks like something "splashed" onto the front element and it effected the lens coating. Try taking a photo of something dark and contrasty and see if anything shows as slightly different colour.
I'm at a loss as to what sort of damaging liquid might have splashed on the lens.. unless maybe it's swan spit! I'll try a few dark and contrasty shots tomorrow when I'm out and see what turns up. It still looks to me like its on the inside, which deepens the mystery. If it doesn't get any worse, or affect the image I'll live with it for a while until I can spare the cash for a repair. cheers
p.1 #11 · Strange marks on 70-200 II front element
Bones74 wrote:
Thanks The second image definitely looks like the coating is damaged. If its on the inside I'd love to know how that happened. It almost looks as if something acidic has eaten it away. I know you have literally hundreds of lenses there; have you seen this before at all?
I have seen something similar a few times - although I've never seen it show up the way the picture you posted did. Now that I'm thinking about, though, is it behind the front element? Because if it is I think the front two elements are a cemented group. It could be an area where the cement isn't applied evenly. That might be a better explanation because the picture you posted almost looks like an interference ring - which might happen if there was an area where the cement was irregular.
p.1 #12 · Strange marks on 70-200 II front element
This is too valuable a lens to have a condition like this. I would hate to see you harm the lens rubbing on it when it should be a Canon repair item.
I would suggest sending it back and seeing if Canon will cover all shipping and make good a repair.
p.1 #13 · Strange marks on 70-200 II front element
Bones74 wrote:
It doesn't look like any fungus growth examples I've seen from images I've seen online. I've just done a shot with an extension tube and bounce flash and then cropped it. This is looking like a coating issue to me. Thoughts? Link HERE
fungus can sometimes cause ring growth like in the first pics but in this better photo yeah it doesn't look like fungus at all, in fact it does look exactly like a coating going bad yikes
p.1 #14 · Strange marks on 70-200 II front element
Bones74 wrote:
I'm at a loss as to what sort of damaging liquid might have splashed on the lens.. unless maybe it's swan spit! I'll try a few dark and contrasty shots tomorrow when I'm out and see what turns up. It still looks to me like its on the inside, which deepens the mystery. If it doesn't get any worse, or affect the image I'll live with it for a while until I can spare the cash for a repair. cheers
Did you shoot around any giant bonfires? I once had a filter (and this why those who say filters never protect anything under conditions expected to be normal are wrong) get some tiny bits of embers apparently land on it and the filter got some odd permanent rings on it, damaged coating, but I think they were a trace different and probably had a center mark too so it's more likely coating going bad or element glue going bad.
p.1 #15 · Strange marks on 70-200 II front element
Try different cleaning solutions. If the one you used is methanol based try one that is water based or vice versa. I tried methanol cleaner on a spot thinking that no matter what it was methanol would be the most effective but it wasn't until I used a water based cleaner that the spot was lifted. So if it is foreign material dried on there it needs to be soluble in the cleaning liquid you apply.
p.1 #18 · Strange marks on 70-200 II front element
RCicala wrote:
I have seen something similar a few times - although I've never seen it show up the way the picture you posted did. Now that I'm thinking about, though, is it behind the front element? Because if it is I think the front two elements are a cemented group. It could be an area where the cement isn't applied evenly. That might be a better explanation because the picture you posted almost looks like an interference ring - which might happen if there was an area where the cement was irregular.
Thanks Roger. I'm fairly certain its behind the front element. I'll contact my local repair centre and ask them how much to replace that front unit.
p.1 #20 · Strange marks on 70-200 II front element
Stu, I am sorry to hear about this problem you are having.
Never seen anything like it. However, two theories already advanced seem plausible to me:
(1) Some sort of corrosive liquid ended up on your lens.
(2) The G1/G2 element doublet optical cement has developed a defect. (in such case you might be able to get a free repair/doublet replacement.)
In either case, you should be able to see if the defect is on the front element (G1) external surface or not, by varying the angle of incident light as well as the visual inspection of the spots.
Cloth dipped in warm water has removed the marks** Phew!