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Haze
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PostPosted: Tue Jul 02, 2013 10:21 am    Post subject: Reply with quote
Olivier wrote:
"cigarette ash on micro-fibre pec pad"
I think you can try it, but won't remove scratches completely, I'm afraid.


Else, what method did you use when your tried to remove haze from your lens ?


First was rubbing alcohol. That didn't work so I moved onto toothpaste, which didn't work, then petrol, then some heavy duty windscreen bug remover for cars.

The bug remover was what scratched the glass.

I will try cigarette ash.

Do I rub it on dry? Or with water?

Other internal elements have haze as well. This lens was caked in concrete and sand when I got it. It was sitting in the previous owner's garage cooking in Sydney's hot summers. That's why the coatings have been damaged.


PostPosted: Tue Jul 02, 2013 10:44 am    Post subject: Reply with quote
I would say dry.


PostPosted: Tue Jul 02, 2013 2:55 pm    Post subject: Reply with quote
Olivier wrote:
I would say dry.


Thanks Oliver


PostPosted: Wed Jul 10, 2013 7:21 pm    Post subject: Reply with quote
parabellumfoto wrote:
Olivier wrote:
"cigarette ash on micro-fibre pec pad"
I think you can try it, but won't remove scratches completely, I'm afraid.


Else, what method did you use when your tried to remove haze from your lens ?


First was rubbing alcohol. That didn't work so I moved onto toothpaste, which didn't work, then petrol, then some heavy duty windscreen bug remover for cars.

The bug remover was what scratched the glass.

I will try cigarette ash.

Do I rub it on dry? Or with water?

Other internal elements have haze as well. This lens was caked in concrete and sand when I got it. It was sitting in the previous owner's garage cooking in Sydney's hot summers. That's why the coatings have been damaged.


OK, I used dry ash from burnt incense sticks. In removing the scratches that I created it worked very well. As for the original haze, no effect.


PostPosted: Wed Jul 10, 2013 10:03 pm    Post subject: Reply with quote
guardian wrote:

Hydrofluoric acid will remove coatings without harming glass.


Actually, hydrofluoric acid does dissolve glass. It is also very, very nasty stuff. Personally, I wouldn't want to go anywhere near it. (Though I've known geologists who use it regularly and are considerably more blasé about it).

It is my understanding that early (single layer) AR coatings were made from magnesium fluoride. It occurs to me that such a coating is probably not going to be removed by HF anyway.

Mark


PostPosted: Fri Jul 26, 2013 3:22 pm    Post subject: Reply with quote
I use AUTOSOL a chrome polish. Apply with cotton bud when cream state - leave to dry and work the fine particulate with a clean bud. It takes ages - be prepared

It requires many treatments to get down to the base layer of the coating where all the Haze seems to live


PostPosted: Mon Jul 29, 2013 9:33 am    Post subject: Reply with quote
I have tested polishing with a drill, a sisal polishing weel and a paste for car glass polishing.
With this setup I could polish lens scratches away.
But there is the big danger to alter the lens surface. I think this could be used to to remove firm haze or permanent fungus defects, which can not be cleaned away with other methodes.


PostPosted: Mon Jul 29, 2013 9:47 am    Post subject: Reply with quote
ZoneV wrote:
I have tested polishing with a drill, a sisal polishing weel and a paste for car glass polishing.
With this setup I could polish lens scratches away.
But there is the big danger to alter the lens surface. I think this could be used to to remove firm haze or permanent fungus defects, which can not be cleaned away with other methodes.


What speed/rpm do you use?


PostPosted: Mon Jul 29, 2013 1:32 pm    Post subject: Reply with quote
About 2000-3000 rpm.
Dependent on coating hardness it takes only few minutes to take the hole coating away.
With that modern hard coating on the Sigma lens it takes me probably (estimated) 15 minutes to get most of the scratches away. I was not able to photograph the small rest of the scratch, but with close inspection it is still visible. But much much less than before the polishing.


PostPosted: Sat Aug 17, 2013 3:24 pm    Post subject: Haze Reply with quote
Why not try in a spectacle store ? advised by Olivier.

I located a technician here who said "can replace the back element of Nikon 20/3.5 of same number of third party. Another technician said can polish the lens but cannot gurantee of its performance. I am seeking advise from my colleagues "After polish the performance of lens will equal to own Nikon or likely to decrease or total collapse. Secondly is it possible the third party back element of same number will perform equal or less to Nikon?. Any help in this respect will be appreciated.


PostPosted: Sat Aug 17, 2013 8:49 pm    Post subject: Re: Haze Reply with quote
gill wrote:
Why not try in a spectacle store ? advised by Olivier.

I located a technician here who said "can replace the back element of Nikon 20/3.5 of same number of third party. Another technician said can polish the lens but cannot gurantee of its performance. I am seeking advise from my colleagues "After polish the performance of lens will equal to own Nikon or likely to decrease or total collapse. Secondly is it possible the third party back element of same number will perform equal or less to Nikon?. Any help in this respect will be appreciated.


Opticians are used to off-the-shelf parts. Laughing Trouble is to find a replacement element having identical curvatures. These are (typically) NOT off-the-shelf parts sold by optical companies for custom optical solutions -- camera lenses have special dimensions.


PostPosted: Sat Aug 17, 2013 9:34 pm    Post subject: Reply with quote
+1

I think they would very unlikely find a replacement with same front and back curvature and same material! Other material gives other (color) dispersion. So optical correction is away.
Polishing ruins surface accuracy - but from my experience this is at least sometimes less a problem.


PostPosted: Sun Aug 18, 2013 4:00 am    Post subject: Haze Reply with quote
Zonev wrote
Quote:
but from my experience this is at least sometimes less a problem.


Thanks for the quick response Visualopsins and Zonev. Will you elabroate i.e the lenes performance will be better. On the haze side photos are white/foggy. Will the polish remove the haze/fog and picture will be sharp.


PostPosted: Sat Aug 24, 2013 9:29 pm    Post subject: Re: Haze Reply with quote
gill wrote:
Zonev wrote
Quote:
but from my experience this is at least sometimes less a problem.


Thanks for the quick response Visualopsins and Zonev. Will you elabroate i.e the lenes performance will be better. On the haze side photos are white/foggy. Will the polish remove the haze/fog and picture will be sharp.


Polish will most likely destroy lens surface form quality, and probably even lens surface smoothness. This could result in problems.
And in case the surface very bad now, it will need a very "deep" polishing process, with high risk of loosing image quality.


PostPosted: Fri Aug 30, 2013 6:09 am    Post subject: Reply with quote
visualopsins wrote:
Recently I had 6.3/400 wundertube with leftover haze in threads pattern, from fungus infection. No solvents could remove it, so I polished the haze away using cigarette ash on micro-fibre pec pad. Either the element was not coated or there was no damage to the coating from the polishing, because the element looks brand new now. I was surprised! Lens IQ improved dramatically, gaining contrast & clarity & brightness.

I also just cleaned some haze from rear elements of mirror lens, with same dramatic improvements in IQ. I think I'm going to keep it now!


What is the active ingredient in ash? Is it not something similar to soap? (Very vague and possibly incorrect primary school memory. Smile


PostPosted: Fri Aug 30, 2013 11:47 am    Post subject: Reply with quote
GP wrote:
visualopsins wrote:
Recently I had 6.3/400 wundertube with leftover haze in threads pattern, from fungus infection. No solvents could remove it, so I polished the haze away using cigarette ash on micro-fibre pec pad. Either the element was not coated or there was no damage to the coating from the polishing, because the element looks brand new now. I was surprised! Lens IQ improved dramatically, gaining contrast & clarity & brightness.

I also just cleaned some haze from rear elements of mirror lens, with same dramatic improvements in IQ. I think I'm going to keep it now!


What is the active ingredient in ash? Is it not something similar to soap? (Very vague and possibly incorrect primary school memory. Smile


Carbon! The fine particles are a minor abrasive.


PostPosted: Sat Aug 31, 2013 7:48 am    Post subject: Re: Haze Reply with quote
ZoneV wrote:
Polish will most likely destroy lens surface form quality, and probably even lens surface smoothness. This could result in problems. And in case the surface very bad now, it will need a very "deep" polishing process, with high risk of loosing image quality.

Same here. The optical co. returned the lens with the remarks" Its back elements are pasted in a frame and if removed chances of breakage. Perhaps they do not have proper machine/tools so locate other ways or will rest on shelf as in the past.


PostPosted: Sun Sep 01, 2013 9:52 pm    Post subject: Reply with quote
Quote:
What is the active ingredient in ash? Is it not something similar to soap? (Very vague and possibly incorrect primary school memory. Smile

Carbon! The fine particles are a minor abrasive.


I will try it, thanks. (Have to find a heavy smoker.. Smile )
I was hoping for a chemical solution, but looks like there is no escape from actually grinding the surface one way or another.
(Similar to other people's experiences, none of the solvents I've tried worked either.)
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