Can I unscratch a lens??

[Ash]

My beautiful 'user' Contax has turned up, and the CZJ Sonnar f/2 collapsible has abuse on the front element as described in the bay auction. The scratches are just surface marks, but at the same time I'm expecting it to cause at least a little trouble.

I was wondering, since the glass had to become smooth somehow to begin with, is there any way to re-polish the surface? effectively un-scratch it by having the whole surface return to a consistent plane? Kinda like smoothing a surface down with finer and finer material.

I guess if there *was* a way it'd be meticulous or expensive (both) and probably not worth it compared to buying a better condition lens, but at the same time it got me thinking.

Unless this is the actual solution, I thought about those people who re-coat lenses. Would getting the lens coated have any impact at all????

Thanks!

 

[Chaser]

these are the guys that can reacoat it...
http://www.araxfoto.com/repairing/

 

[Ash]

Chaser, thats what I thought until I read this:

"[SIZE=-1]We NOT work with 35mm cameras and lenses, sorry."[/SIZE]

 

[schmoozit]

Arax will be able to fix the scratch as well. I've heard good things, but have no experience personally.

 

[Pherdinand]

There are two options, basically:
1: Using a time machine
2: Unscratch Mask filter in Photoshop.

 

[Ash]

I like option one... 😀

I found a few links to people in america. Maybe it'll cost more than it's worth. Maybe I could find a Sonnar with damaged iris/back element, but a nice front element and play swapsies?

 

[Jocko]

Buy a nice Helios 103 🙂

Cheers, Ian

 

[Ash]

Buy a nice Helios 103 🙂

Cheers, Ian

Can I swap the front element from it?? 😀 😀


Seriously though I have the J-8m that's immaculate, so I'll use that if I can't get on with the Sonnar. It's a shame to waste the lens though.

 

[Pherdinand]

Probably not, but a Jupi-8 front lens might fit just well😀
Is that what you mean with your 8m?

 

[Kim Coxon]

Ash,
The last time I emailed them, they were happy to deal with individual elements. What thet won't do is take a 35mm lens and repair it. As long as you remove the lens yourself and re-assemble when it comes back, they are happy to do it. 😉

Kim

Chaser, thats what I thought until I read this:

"[SIZE=-1]We NOT work with 35mm cameras and lenses, sorry."[/SIZE]

 

[Ash]

Yea J-8m = Jupiter-8m, its my laziness. I'd prefer not to butcher the lens, but if it DOES fit then that would mean I can buy a cheap'un off the bay and swap it maybe.


Course, then I gotta worry about the seller on the bay givin me a scratched lens


EDIT:

Kim, I guess I'll have to disassemble it for butchering a jupiter-8 either way, so maybe I could send the element to them as well - that way if the Jupiter-8 thing fails, I can get the lens sorted out. So is it $30 or $15?? Their site is a little confusing on that

 

[clintock]

You can un-scratch a lens yourself, simply read about telescope mirror grinding and learn how to make a pitch lap.
You melt the pitch onto a round block-something like a wooden thread spool glued to a small board for example, then press the lens element into the pitch while there is something like plastic wrap between the lens glass and pitch, so it takes the shape but won't stick. Then cut groves in the pitch once it fully cools so the grit slurry can get out as the lens glass is manually moved against the lap.
Tiny quantities of pitch and the right polishing powder can be bought from got grit..http://www.gotgrit.com/
Using the pitch lap, grind the surface smooth, then have the element recoated at a place that does optical coatings, such as http://www.thinfilmcoating.com/

I have a summicron that I have been plannng to do the above to for four years now, but have not gotten to it-it's on my list of things that never get done because I am on the damn computer too much!
I'd call the thinfilmcoating place to make sure they are still there and not just an empty website.

I think the whole operation can take place in a kitchen sink, and should only take less than an hour to polish, once the lap is made.. The curve of the lap is made by the glass itself, thus the grinding should not effect the lens curve..

 

[jlw]

IF the scratch is deep enough to feel when you run your fingernail across it, you basically can't fix it. That means it has gone into the glass itself, and the only way to "remove" it would be to remove enough glass to get down level with the bottom of the scratch. Since it's the thickness of the glass that controls how much it bends the light, removing thickness would change the optical design of the lens. You'd probably wind up with a scratch-free but unsharp lens.

Telescope mirrors are different -- their optical properties are determined by their shape, not by their thickness.

 

[ben lloyd]

Ash,

Email Arax, unless its a recent policy change they do repolish/ recoat lenses, as it says further down the page, you have to send in the glass only, nothing else. There are a few threads floating around about them polishing and recoating early summicrons and elmars.

EDIT:
Beaten to it again!

 

[Ash]

jlw, I can feel a slight change in texture when I run my nail VERY gently over it, but my baby-soft skin can hardly feel a thing 😉

 

[Kim Coxon]

The answer is on their website.

Leica, Carl Zeiss Jena, all other lenses could be polished and multi-coated for $15 for surface or $30 for one glass independent from the lens size. You should send the glass only without any metallic parts. For bulk order you'll have discounts. E-mail us for details.

It's basically $15 per surface ie $30 per element.

Kim

Kim, I guess I'll have to disassemble it for butchering a jupiter-8 either way, so maybe I could send the element to them as well - that way if the Jupiter-8 thing fails, I can get the lens sorted out. So is it $30 or $15?? Their site is a little confusing on that

 

[Ash]

That's what I was wondering. I guess I'd have to get the whole element done, rather than waste time with only one side.

Kim, fancy a bit of moola in return for dismantling and reassembling a CZJ Sonnar? 😀 😀

 

[Ash]

And moola means MONEY before anyone gets any ideas! 😀

 

[Xmas]

Ash

If the Sonnar is like a J8(m) it only needs a screwdriver, and care. note I've not had mine apart. It is a single glass element so does not need separation e.g. like an Elmar.

If you are just being fussy it may be better keeping the Sonnar intact and using the J8m you have, you might prefer the click stops? The value to a collector will drop if you coat, like if you synchronise, and a Contax is not a high volume camera like a Kiev.

To coat they have to repolish the lens to key the coating unto the glass properly and most marks will dissappear... i.e. they remove a micro layer with really fine abrasive polish, like Brasso but on a machine that maintains the radius of curvature. The thickness of a triplet is critical to performance but not so critical that they cannot repolish it.

Noel

 

[Ash]

Noel, my interest doesn't really lie with the collector. I want the lens/camera to perform the best it can under my current budget, and if I ever got rid of it I'd be selling to someone on RFF. I'm sure you guys would prefer the lens with a reconditioned front element???