[flyingfishfinger]

Hi,
I recently (about 2 weeks ago) took my brand new 16-85mm out to Mono Lake and got it pretty well sprayed with lake water (kayak excursion).
I didn't think much of it since the mineral / salt deposits & white stains washed off the body and everything else fine, but as I was clearing up some equipment I noticed that I hadn't cleaned a few of the stains off the front of the lens.
When I did, I found that they appear to have left a stain on the glass I cannot remove.

Is it possible that the mineral / salt content of the splash has damaged the front coating? If so, how to fix it? If not, what else can I try to clean it?

Thanks,
R

[aaacb]

Hi and welcome to the forums!

Could you add more details how you tried to clean the front element and show the stains in a photo? In my experience, the SP coatings on the external elements are very tough and not easily scratched or damaged by salt water (but I've never left it dried there for extended periods of time).

You can find countless tutorials on lens cleaning on the web. I for one clean my lenses the following ways:
a) With an air blower, for light dust
b) Air blower + brush (lens pen has a brush on one end) + lens pen + air blower again for any dust that was left by the lens pen. This works fine for fingerprints or light dust that's more stubborn.
c) If there's "stuff" on the front element and it could scratch the coatings, including dried salt water, I use a wet wipe after the brush but before the lens pen

[Pentax Syntax]

I second the methods described above. The SP coating on the 16-85 is pretty tough. If you get all particulates off of the lens you can get most things off with a lens pen. You may have to use a hot breath to slightly fog the lens then remove with lens pen. I will also add that a multicoated protection or UV filter is prudent when shooting around water....particularly salt water. I learned that on a whale watching trip where camera (K-3) and lens (16-85) were soaked. The protective filter had salt stains that were hard to remove but the lens was completely protected.

[flyingfishfinger]

Hi,
They're hard to photograph, I just tried and failed. At certain angles they catch the light, but from other angles they can't be seen at all. And when they do catch the light, it seems they don't have enough contrast to focus on.

For the cleaning, I started with just a microfiber cloth and escalated to a light spray of 99.9% isopropyl alcohol....made no difference either way.

I can't "feel" any residue left on the stained areas, the actual dried salt came off pretty easily with a wet wipe and now they look pretty smooth. Hence my suspicion / question about the coating...

R

---------- Post added 09-16-18 at 12:44 PM ----------

I will also add that a multicoated protection or UV filter is prudent when shooting around water....particularly salt water.

Yeah... I haven't gotten around to picking one up in the right size for this lens yet.

R

---------- Post added 09-16-18 at 12:46 PM ----------

I should add that the water in Mono Lake is actually both extremely salty and extremely alkaline to the point where the entire lake feels soapy (ph 10, I believe).

I wonder if that makes a difference...

[Pentax Syntax]

Hi,
They're hard to photograph, I just tried and failed. At certain angles they catch the light, but from other angles they can't be seen at all. And when they do catch the light, it seems they don't have enough contrast to focus on.

For the cleaning, I started with just a microfiber cloth and escalated to a light spray of 99.9% isopropyl alcohol....made no difference either way.

I can't "feel" any residue left on the stained areas, the actual dried salt came off pretty easily with a wet wipe and now they look pretty smooth. Hence my suspicion / question about the coating...

R

---------- Post added 09-16-18 at 12:44 PM ----------



Yeah... I haven't gotten around to picking one up in the right size for this lens yet.

R

---------- Post added 09-16-18 at 12:46 PM ----------

I should add that the water in Mono Lake is actually both extremely salty and extremely alkaline to the point where the entire lake feels soapy (ph 10, I believe).

I wonder if that makes a difference...

The lens pen will do wonders on both filters and lenses. They make a version for both. I believe it will take care of the problem. The SP coatings might be able to resist alkali but pH 10 is pretty alkaline. Worth a try with the lens pen. But don’t sweat it if something remains. It will likely have NO effect on image quality

[flyingfishfinger]

You're talking about this version?

I'll give it a try and see.

In other news, the lake water also seems to have damaged the rear dial (I'm still getting white deposits materializing at all the body seams after several fresh water spraydowns) so I might have to dismantle the camera as well to clean it out properly

R

[Pentax Syntax]

You're talking about this version?

I'll give it a try and see.

In other news, the lake water also seems to have damaged the rear dial (I'm still getting white deposits materializing at all the body seams after several fresh water spraydowns) so I might have to dismantle the camera as well to clean it out properly

R

Yes that one is great. They also sell a kit with all of the sizes for cleaning viewfinder etc:

Lenspen Pro Pack with DSLR Lens, MicroPRO & FilterKlear Cleaning Pens with Cloth Pouch https://www.amazon.com/dp/B01E7EV210/ref=cm_sw_r_cp_api_n0RNBbSMW5BZP?tag=pentaxforums-20&

The other problem sounds more difficult. My K-3 had a lot of salt after some fresh water cleanings and the salt caused the latch holding the built in flash to fail. I now hold it down with rubber bands 😒

[flyingfishfinger]

Yeah.... my flash hasn't worked in years either, I think the release mechanism is totally broken (so the opposite problem from yours, mine can't open without being pried!)

This K-5 is getting on in years, I've had it since 2011 and it's been VERY well used (you should see the scuff marks on the body), so I'm almost comfortable trying to open and clean it myself... the worst that can happen is I'm forced into a body upgrade

R

[Pentax Syntax]

Yeah.... my flash hasn't worked in years either, I think the release mechanism is totally broken (so the opposite problem from yours, mine can't open without being pried!)

This K-5 is getting on in years, I've had it since 2011 and it's been VERY well used (you should see the scuff marks on the body), so I'm almost comfortable trying to open and clean it myself... the worst that can happen is I'm forced into a body upgrade

R

Good luck with the cleaning. Curious if you can get all of the corrosive material out. I am holding out for the K-3ii replacement myself. I use the K-3 in some crazy environments (hiking, Kayaking, rock climbing) so its had its share of abuse also.....

[pcrichmond]

I should add that the water in Mono Lake is actually both extremely salty and extremely alkaline to the point where the entire lake feels soapy (ph 10, I believe).

If I remember right Mono is high in the Calcium side (carbonates, chlorides, sulfates, etc) along with borates and other alkaloids. I'd be curious to hear from others on the forum before you try this but I wonder if using a dilution of vinegar/water on a micro fiber might remove the residual. I live down the road from Mono and have never thought about the spray when photographing there. I usually wipe immediately when done and never had residue issues yet but there will come the day (I'm sure) and knowing how another photographer has successfully dealt with this will be a big help.

[flyingfishfinger]

Ordered the pen, I'll report back once I get it...

Mono Lake water is nasty stuff. Tastes bad too!

R

[Kozlok]

If it is a salt or mineral, I would not use a lens pen to clean it. You will drag the mineral deposits around and scratch the front element.

I would use a small soft brush and distilled water, be careful to not let it get to the mount end. I’d have someone hold it mount end up. It may take some time, but I’d resist using much mechanical force.

[Not a Number]

If the deposits are alkaline in nature (salts, calcium carbonate) then you want to try a weak acid to clean with. Try a diluted white vinegar solution say four parts water to one part vinegar. Dab the solution on with a moistened microfiber cloth or lens cleaning tissue. Do not rub at any time. Wait a few seconds. Dab it off with a cloth moistened with distilled water. Repeat a few times. If no effect, give up - the coating may have been etched.

[Wheatfield]

If the deposits are alkaline in nature (salts, calcium carbonate) then you want to try a weak acid to clean with. Try a diluted white vinegar solution say four parts water to one part vinegar. Dab the solution on with a moistened microfiber cloth or lens cleaning tissue. Do not rub at any time. Wait a few seconds. Dab it off with a cloth moistened with distilled water. Repeat a few times. If no effect, give up - the coating may have been etched.

The best answer so far.
I had no idea mono lake was so alkaline. That is right up there with floor cleaners for potency. That's going to be pretty salty salt. I wouldn't be rubbing that stuff around on a front element after it had dried. There are times when a protective filter is the right thing to do, I'm thinking photographing at that lake would be one of those times.

[flyingfishfinger]

Yeah it looks like it's coating damage as far as I can tell. My breath condenses differently on the areas, it catches light at a different angle and the light acid method had no effect whatsoever.

I just hope it doesn't impact image quality...thoughts around this?

R