Help me identify what is wrong with a lens I purchased.

Radost · May 12, 2022

Steve906 said:
Hi, I worked there for the past 8 years, Also Cooke and Taylor Hobson previously, would love to have go at this just for the challenge.!!!

Sounds cool. Might be too expansive to ship to UK and back.

Radost · May 12, 2022

My philosophy is: Those lenses are finite. If I can breath new life and save a lens soul I will. I have done the same for a few folder cameras. Cost me more to buy and repair than buying one in good condition. But I saved them. Feels good.

Radost · May 12, 2022

Apart from the front element the lens is in good shape.

Radost · May 12, 2022

Should I try lighter fluid?

Steve906 · May 12, 2022

Are you sure the problem is on the front face? Your original picture looks as if the cement has been attacked by fungus, I've seen many like it (though not quite as bad). If it is in the cement it's not as difficult to re-cement as it sounds, using some UV cure such as Norland. even if etched into the glass the cement can fill and hide problems quite well.
We always used acetone to clean as long as there are no vulnerable plastic parts.

Radost · May 12, 2022

Yes it is the front I can feel it with my finger.

grat · May 12, 2022

Lighter fluid is going to evaporate too quickly. I'd soak it (just the front element) in some non-ammonia glass cleaner.

It looks pitted. That could be surface buildup, which might be cleanable. But if it's pitted, well-- it had a good life. We assume.

xkaes · May 12, 2022

I'd use lighter fluid -- and a match.

Sirius Glass · May 12, 2022

xkaes said:
I'd use lighter fluid -- and a match.

What about sand paper? No seriously, try what you can with water and lens cleaner, then get some estimate before you make any decisions.

Radost · May 27, 2022

Opened the front of the lens and removed the front element. The entire lens is in 100% preserved condition. Even the back side of the glass of the from element. Will try to soak it in lighter fluid. Or should I use another liquid?

250swb · May 28, 2022

From the first photo it looks like corrosion to the glass with indentations caused by an alkaline solution, in the later photos it look like bubbles on the surface, so the lighting in the photos is confusing me. However I've seen some wild ideas when it comes to repairs and we all remember the genuine trick where if you get a scratch in the front element fill it with black ink to stop reflections, well the same is true if you fill it with clear varnish. So has the front element been varnished in the past maybe, or has somebody painted something on to make it soft focus? So I wouldn't use anything alkaline to clean it like paint some strippers, but maybe try rubbing along an edge with nail varnish remover to see if that shifts anything?

guangong · May 28, 2022

Many moons ago I asked the repair manager at Leica what they used to clean lens glass. His answer: pure ammonia.

Radost · May 29, 2022

Tried fluid and Aceton.
No difference.

bernard_L · May 29, 2022

Radost said:
I can feel it with my finger.

This means the glass is pitted. Hopeless. Too bad.

pentaxuser · May 29, 2022

bernard_L said:
This means the glass is pitted. Hopeless. Too bad.

How can you be so sure? Surely any coating that may be removable but that is on the lens means that you'd feel it with your finger but that doesn't mean the glass is necessarily pitted?

pentaxuser

Don_ih · May 29, 2022

Radost said:
Tried fluid and Aceton.
No difference.

At this point, maybe you should soak the front element in acetone - for hours or a day. You can also try alcohol.

bernard_L · May 29, 2022

pentaxuser said:
How can you be so sure? Surely any coating that may be removable but that is on the lens means that you'd feel it with your finger but that doesn't mean the glass is necessarily pitted?

pentaxuser

Typically, an individual (if multi-layer) layer in AR coating is 1/4 of a wavelength; taking into account the index n>1, that amounts to 0.1 micrometer. Even multilayer, still well below 1 micrometer.

I know from experience that fingers can sense maybe 1/100mm=10µm. But <1µm, no way.

Craig · May 29, 2022

bernard_L said:
Typically, an individual (if multi-layer) layer in AR coating is 1/4 of a wavelength; taking into account the index n>1, that amounts to 0.1 micrometer. Even multilayer, still well below 1 micrometer.

I didn't read the comment as something in the anti-reflective coating, but rather something that is depositied on the lens surface. I know it isn't, but it looks like a layer of frost on the lens.

Radost · May 30, 2022

Don Heisz said:
At this point, maybe you should soak the front element in acetone - for hours or a day. You can also try alcohol.

I will try the aceton for a day.

grain elevator · May 30, 2022

If it doesn't come off, what do you have to lose with trying to polish it? Might at least become an interesting portrait lens. Or you can still look for a donor front element if it doesn't work out.

dxqcanada · May 30, 2022

Glass Polish 1.3 microns

markjwyatt · May 30, 2022

Maybe better:

dxqcanada · May 30, 2022

markjwyatt said:
Maybe better:

broken link

markjwyatt · May 30, 2022

dxqcanada said:
broken link

Works for me. Try this:

dxqcanada · May 30, 2022

Hmm, Firefox doesn't like it ... but Edge is Ok with the link ... hmm.

Help me identify what is wrong with a lens I purchased.

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