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Soligor 100mm f/2, worth to keep?
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PostPosted: Fri Jul 20, 2018 2:43 am    Post subject: Soligor 100mm f/2, worth to keep? Reply with quote

Got a Soligor 100mm f/2, pretty rare lens. Overall condition is good. One problem is an inner lens element has very thin irregular shaped haze covering the entire element and the inner element has many scratches. It looks like someone tried to cleaned the haze and couldn't do a decent job. I understand the haze sometimes is hard to clean due to coating damage. Another thing is it is in OM mount and I never have an OM mount lens before. The mount has two tabs. By pressing and holding the tabs, the lens is in manual mode, similar to the A/M switch in a M42 lens. However, somehow I have to hold the two tabs and can't really engage this manual mode without releasing my fingers. While in a M42 lens, placing the switch to the M position will engage the manual mode. So is there anything wrong with this OM mount or I didn't do it correctly, or after mounting on an Olympus body, the manual mode can be engaged with the camera body/mount.

Here is a photo showing the scratches and haze (more dominant in the center portion); I placed a flashlight from the lens rear. Under regular light, the glass doesn't seem to be this bad.

The lens was sold for around $100. Do you guys think it is worth to keep it? Thanks very much!

#1


PostPosted: Fri Jul 20, 2018 8:09 am    Post subject: Reply with quote

You might re-polish the affected suface with cerium oxide:
https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Glass-Polishing-Compound/?N=5002385+3293082872&rt=rud

Of course, that surface will loose its (single) coating. Probably this won't influence the original performance of the lens (it's just one uncoated surface, and up to six uncoated surfaces were considered acceptable in old days).

Stephan


PostPosted: Fri Jul 20, 2018 3:50 pm    Post subject: Reply with quote

stevemark wrote:
You might re-polish the affected suface with cerium oxide:
https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Glass-Polishing-Compound/?N=5002385+3293082872&rt=rud

Of course, that surface will loose its (single) coating. Probably this won't influence the original performance of the lens (it's just one uncoated surface, and up to six uncoated surfaces were considered acceptable in old days).

Stephan


Thanks. I think polishing and probably recoating is the ultimate cure; but this work is too delicate without the right machinery. Have you ever done this? How to control the thickness to be polished and also keep the curvature of the lens? I am thinking of making a reverse mold first.


PostPosted: Fri Jul 20, 2018 5:04 pm    Post subject: Reply with quote

I have seen some cases like this.
If its just coating damage and not actual scratches the coating can be polished off with a very light scrubbing with polishing compound, and the practical effect on the lens will be negligible.
But test the lens first, as coating damage may not really affect results in the first place.
It might be good enough as it is.

Actual scratches are quite difficult to remove with polishing compounds. Or not at all.
I have tried to repair badly scratched lenses before, one being a Nikkor 50/1.4 front element in an otherwise mint lens.
The front element was totalled, it had a mass of fine scratches all over the center-front, making for very poor, cloudy results.
To avoid looking for a replacement front element, I tried polishing. Polishing it led to a somewhat brighter but quite poor results with poor resolution. Too much polishing can lead to uneven distortion, etc.


PostPosted: Fri Jul 20, 2018 5:24 pm    Post subject: Reply with quote

vivaldibow wrote:
stevemark wrote:
You might re-polish the affected suface with cerium oxide:
https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Glass-Polishing-Compound/?N=5002385+3293082872&rt=rud

Of course, that surface will loose its (single) coating. Probably this won't influence the original performance of the lens (it's just one uncoated surface, and up to six uncoated surfaces were considered acceptable in old days).

Stephan


Thanks. I think polishing and probably recoating is the ultimate cure; but this work is too delicate without the right machinery. Have you ever done this? How to control the thickness to be polished and also keep the curvature of the lens? I am thinking of making a reverse mold first.


I have a lens with badly hazed coating on one side of an inner element, and this is exactly the process I am planning to take.

I've got the cerium oxide, and I'm going to try and make a a reverse mould from 'Sugru' - a mouldable silicone. This should be soft enough to not damage the glass and firm enough to maintin the shape. But as yet, I haven't had time to try it.

https://sugru.com/






..


PostPosted: Fri Jul 20, 2018 7:43 pm    Post subject: Reply with quote

Lloydy wrote:
vivaldibow wrote:
stevemark wrote:
You might re-polish the affected suface with cerium oxide:
https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Glass-Polishing-Compound/?N=5002385+3293082872&rt=rud

Of course, that surface will loose its (single) coating. Probably this won't influence the original performance of the lens (it's just one uncoated surface, and up to six uncoated surfaces were considered acceptable in old days).

Stephan


Thanks. I think polishing and probably recoating is the ultimate cure; but this work is too delicate without the right machinery. Have you ever done this? How to control the thickness to be polished and also keep the curvature of the lens? I am thinking of making a reverse mold first.


I have a lens with badly hazed coating on one side of an inner element, and this is exactly the process I am planning to take.

I've got the cerium oxide, and I'm going to try and make a a reverse mould from 'Sugru' - a mouldable silicone. This should be soft enough to not damage the glass and firm enough to maintin the shape. But as yet, I haven't had time to try it.

https://sugru.com/






..


Glad to hear you had the same idea! Thanks for the link. Very interesting and useful stuff. That's still a meticulous job and I am not sure if I am confident enough not to screw up the glass. Sad


PostPosted: Fri Jul 20, 2018 9:38 pm    Post subject: Reply with quote

After a quick Google of "lens polishing recoating"
https://www.ducloslenses.com/pages/glass-polishing-recoating
http://www.kantocamera.com/english/repair/repair.html
This one probably will be expensive http://www.ultraflat.com
It appears http://www.focalpointlens.com is now closed for good.


PostPosted: Sat Jul 21, 2018 2:43 am    Post subject: Reply with quote

Lightshow wrote:
After a quick Google of "lens polishing recoating"
https://www.ducloslenses.com/pages/glass-polishing-recoating
http://www.kantocamera.com/english/repair/repair.html
This one probably will be expensive http://www.ultraflat.com
It appears http://www.focalpointlens.com is now closed for good.


Thanks. These service is available. One of them is in Japan. Good the first one is in US. I am gonna give them a call. Will find out!


PostPosted: Sat Jul 21, 2018 4:01 am    Post subject: Reply with quote

As I am waiting for the OM-NEX adapter, I mounted an MD-NEX adapter to my Sony a3000, then manually placed the lens onto the MD-NEX adapter. Took a test shot of a paper bag by moving the camera to focus. It seem the lens is pretty sharp. The photo is a 100% crop and although it is slight OOF, the lens resolves the "Ruffles" on the paper bag. I've taken the shots of the same scene using different Soligor/Vivitar lenses. Besides Vivitar 90mm f/2.5, not too many of them show this much of details. Certainly I can tell the contrast is not great. Not sure if it is because of the f2 aperture or more due to the haze, or there is some light leakage between the lens and the adapter.

#1


PostPosted: Sun Jul 22, 2018 10:26 pm    Post subject: Reply with quote

The real effects of damage are often overblown. I've seen numerous lenses that by all accounts should have headed straight to the trash bin, but still produced great shots. Over the past year I had exactly one case where I was like "Wow, that's bad, did not see this coming".


PostPosted: Mon Jul 23, 2018 4:29 am    Post subject: Reply with quote

Gardener wrote:
The real effects of damage are often overblown. I've seen numerous lenses that by all accounts should have headed straight to the trash bin, but still produced great shots. Over the past year I had exactly one case where I was like "Wow, that's bad, did not see this coming".


You are absolutely right. I am waiting for the OM-Nex adapter to have some more test shots. Lost of contrast due to haze could be most significant.


PostPosted: Mon Jul 23, 2018 5:02 am    Post subject: Reply with quote

vivaldibow wrote:
Gardener wrote:
The real effects of damage are often overblown. I've seen numerous lenses that by all accounts should have headed straight to the trash bin, but still produced great shots. Over the past year I had exactly one case where I was like "Wow, that's bad, did not see this coming".


You are absolutely right. I am waiting for the OM-Nex adapter to have some more test shots. Lost of contrast due to haze could be most significant.


... and that's easy to correct in PP! Wink


PostPosted: Wed Jul 25, 2018 5:33 am    Post subject: Reply with quote

kds315* wrote:
vivaldibow wrote:
Gardener wrote:
The real effects of damage are often overblown. I've seen numerous lenses that by all accounts should have headed straight to the trash bin, but still produced great shots. Over the past year I had exactly one case where I was like "Wow, that's bad, did not see this coming".


You are absolutely right. I am waiting for the OM-Nex adapter to have some more test shots. Lost of contrast due to haze could be most significant.


... and that's easy to correct in PP! Wink


After I tried the lens with the OM-NEX adapter, I decided to return it. Wide open the contrast is fairly low and this results in details washed out and focusing slightly difficult.