I bought this lens off a friend a few weeks ago. Today I went to ship it to a buyer and was cleaning it up as I do with all lenses before I ship them. There was a tiny tiny mark on the side of the glass so I took a microfiber glass cleaning cloth like I always do on lenses and started cleaning it. It started to spread and smudge presumably the coating on the glass. I have never seen this before. I had to refund the buyer and admit that I messed up the lens. Is this repairable? Will it affect image quality? I did nothing but use a microfiber cloth and it really did a number on this coating quickly. Never seen anything like that. Any ideas?
This lens has a fluorine coating on the front element which can be susceptible to this type of damage. There was a post a year or two ago here where someone messed up their 600/4 in a similar manner. You'd have to test it to determine if it results in any visible image quality degradation. Probably not in 'normal' conditions, but uncertain if, for example, strong backlighting could cause additional flare.
I believe the only fix is to replace the front element, especially if the intent is to resell it (unless you want to take the hit on the resale).
Roger Cicala at Lens Rentals is not a fan of fluorine coatings:
"As an aside, we despise the new fluorine front and rear coatings and consider them a significant step backward in durability; but that’s just our opinion."
I own a copy of the 28-70/2 and use it without a protective filter. At some point I used it in a light rain situation where some water still managed to stick to the front element and left a couple faint, small watermark rings. Based on your experience, it's likely best I try not to remove these!
rscheffler wrote:
This lens has a fluorine coating on the front element which can be susceptible to this type of damage. There was a post a year or two ago here where someone messed up their 600/4 in a similar manner. You'd have to test it to determine if it results in any visible image quality degradation. Probably not in 'normal' conditions, but uncertain if, for example, strong backlighting could cause additional flare.
I believe the only fix is to replace the front element, especially if the intent is to resell it (unless you want to take the hit on the resale).
Really? The coating on this lens could smudge that easy? Is that a defect?
rscheffler wrote:
Roger Cicala at Lens Rentals is not a fan of fluorine coatings:
"As an aside, we despise the new fluorine front and rear coatings and consider them a significant step backward in durability; but that’s just our opinion."
might be worth trying some 90% isoproply aclochol. If that is a water smudge like you get on some wood finishes, its just moisture trapped below/within the coating. IPA can potentially dry it out. Just a bit on a q-tip. If you keep it to that area only, can't make things worse.
rscheffler wrote:
This lens has a fluorine coating on the front element which can be susceptible to this type of damage. There was a post a year or two ago here where someone messed up their 600/4 in a similar manner. You'd have to test it to determine if it results in any visible image quality degradation. Probably not in 'normal' conditions, but uncertain if, for example, strong backlighting could cause additional flare.
I believe the only fix is to replace the front element, especially if the intent is to resell it (unless you want to take the hit on the resale).
RustyRus wrote:
Really? The coating on this lens could smudge that easy? Is that a defect?
I would have to revisit the thread about the 600mm lens damage (I think it was a 600mm lens) and how that happened. Not sure if certain cleaning fluids are more likely to weaken the coating and result in this type of damage, but as noted above, OP didn't use anything other than moisture from his breath.
I have this lens and have not found it to be more sensitive than others with "normal" cleaning to remove light dust and perhaps a smudge or two. But admittedly I have not cleaned the front element that often with direct physical contact because it really hasn't needed it. And when I have, it has usually just been with a dry microfiber cloth. I didn't realize until now that it has a fluorine coating, which probably explains why it tends to stay cleaner than I would expect for such a large surface area on a lens I use very frequently (and never with a protective filter). My cleaning of it is mostly with a blower bulb to remove dust and occasionally with a dry cloth.
Fluorine lens coatings appear to be a tradeoff. From my experience with it on the 200-400 and 85/1.4L IS, it definitely keeps water, oil and debris from sticking excessively. But apparently it's more fragile, as suggested by Roger Cicala in the link in my previous (edited) post. I'm guessing as a rental house, they see a lot more of this because of the overall higher use their equipment receives. In this blog post he says fluorine coated lenses are more susceptible to coating scratches.
I use ROR from the spay bottle and haven't had problems in general. But as mentioned, I rarely wet clean the fluorine coated lenses because they're usually not smudged and only dusty, where a blast of air is usually enough.
rscheffler wrote:
Not all RF lenses have fluorine lens coatings.
I use ROR from the spay bottle and haven't had problems in general. But as mentioned, I rarely wet clean the fluorine coated lenses because they're usually not smudged and only dusty, where a blast of air is usually enough.
The RF 100-500 has it. Even the EF 500/4 IS II does also. Both need cleaning often enough in Sernegetti.
Now I'm nervous.
That looks similar to smudging I've seen when cleaning the front element of any lens with a modern coating. It usually comes right off by wet-cleaning the front element with a disposable Zeiss lens wipe. The wipes are usually a little too wet when first unsealing the package so I apply a few blows from a rocket blower on the wipe before applying it to the lens.
You can help avoid the smudges by using the rocket blower on the front element prior to cleaning it - that will clear out the dust that would usually cause this smudge when dragged with the cleaning cloth.
I would avoid using microfiber cloths on front elements, at least as the first tool applied to the job. It's too easy for particulates from previous use to get stuck on the cloth and be dragged over the front element. My strategy is to use the rocket blower first, then a disposable Zeiss wipe, then if there are any streaks (usually not) a microfiber cloth. Also, by limiting the microfiber cloth to cleaned elements you prevent it from getting dust on it that would be a problem in a future use.
nimrazer wrote:
Before I came across this thread, I actually used ROR to clean the exact same lenses mentioned here—my RF28-70 and RF600mm/F4.
Good news: nothing went wrong, and the lenses are spotless.
Bad news: Should I be worried about it now?
Probably not. In the 600mm lens thread the OP apparently cleaned the front element with some sort of alcohol. ROR may contain alcohol (I'm not sure), but if it does, it is not purely alcohol. It's also unclear how much pressure was used to clean these two lenses. I know I've been guilty of using more force when a spot or smudge won't apparently budge. And that's probably the wrong approach with fluorine coatings. Because that spot is probably a chip in the coating and more pressure will just weaken it even more. I suspect if these coatings were truly very delicate that there'd be many more posts like this one and Canon and other brands probably wouldn't put them on consumer lenses in the first place.
Section 2-Hazardous Ingredients/Identity Information
Hazardous Components (Specific Chemical Identity: Common Names)
Ammonia 26° 0.775% % Non Hazardous
Sodium Chloride 0.830% % Non Hazardous
Isopropyl Alcohol 4.266% % Non Hazardous
Liquid Soap 9.011% % Non Hazardous
Distilled Water 85.118% % Non Hazardous
