Replace, Keep, or Sayonara? 80mm Planar Rear Element

yessammassey · Jul 31, 2020

Junk shop find attached to a KE-46A. All glass surfaces are pristine on both cells, except exterior surface of rear element has some very aggressive cleaning marks as shown. This is after a wipe down with Eclipse fluid.

Looks like the element is held in place by a single retaining ring. Would sourcing a replacement rear element be advisable? Where would I even start to look for one? (Besides the ubiquitous auction site, please)

These shallow but pervasive scratches are not repairable, right? And will lower contrast, etc.?

Donald Qualls · Jul 31, 2020

Are the specks fungus?

For scratches, I recall the standard advice for a single scratch or two (or even a pretty bad gouge) was to fill the defect with India ink. That turns scatter into absorption, and will reduce the flare induced by scratches to a huge extent. Worth trying before you spend money on a "solution" that may not be an improvement (replacing elements with others of the same lens type is iffy -- sometimes it works, sometimes it doesn't).

RalphLambrecht · Jul 31, 2020

Donald Qualls said:
Are the specks fungus?

For scratches, I recall the standard advice for a single scratch or two (or even a pretty bad gouge) was to fill the defect with India ink. That turns scatter into absorption, and will reduce the flare induced by scratches to a huge extent. Worth trying before you spend money on a "solution" that may not be an improvement (replacing elements with others of the same lens type is iffy -- sometimes it works, sometimes it doesn't).

I'd get another used lens.

yessammassey · Jul 31, 2020

It goes in the drawer, then. To wait. Would it even be worth testing to see if I could get a decent image out of this?

JPD · Jul 31, 2020

yessammassey said:
It goes in the drawer, then. To wait. Would it even be worth testing to see if I could get a decent image out of this?

You probably would, but those scratches will affect the contrast, and since it's the rear element maybe also sharpness, throwing off some of the image forming rays. It could be nice for portraits, though, so it could be worth to test the lens.

chris77 · Aug 1, 2020

JPD said:
You probably would, but those scratches will affect the contrast, and since it's the rear element maybe also sharpness, throwing off some of the image forming rays. It could be nice for portraits, though, so it could be worth to test the lens.

Of course, test it by all means!

guangong · Aug 1, 2020

Would it be possible to polish surface to remove cleaning marks? If so, would cost of polishing cost more than buying a replacement lens?

Donald Qualls · Aug 1, 2020

Polishing enough to remove the scratches would also remove the coating on that rearmost surface, so might or might not be an improvement. Plus the possibility of aggressive polishing changing the surface shape enough to affect the image.

If it were mine, I'd try to fill the scratches with India ink and then test the lens. I've got a Jupiter 12 that's in much worse shape than that (probably damaged by contacting the metal shutter curtain in a post-War Contax body, if I had to guess), and the images turned out to have some central softness -- so I replaced the lens. I also bought another (same optics, L39 mount) with trashed mechanicals and I'll get around to trying a rear group transplant at some point...

yessammassey · Aug 14, 2020

Thanks for the answers. Will probably test once I finish getting my baby crown graphic (with 6x7 rollfilm back) set up.

I’ve had my eye out for the non-SLR Planars and Xenotars since reading Chris Perez’s stories about the detail rendition of mid-century Rollei 6x6’s. I very much doubt the one I got will live up to the legends.

The lens came with a box of other things that I’m selling to make up the price I paid for it, but I chose this instead of a 100/4 Xenotar. My spin of the used gear roulette wheel was unlucky, and now I’ll always wonder if the Xenotar would’ve been a gem.

AnselMortensen · Aug 15, 2020

I suggest trying it out in varying light conditions, particularly back-lit subjects.
I have a lens that had micro-pitting to the front element and had very low contrast and high flare...I tried a last-ditch, make-it-or-break-it "fix" recommended by a forum member that helped a lot, but don't want to share it unless your lens is completely unusable.

beemermark · Aug 15, 2020

I'm not bothered by a few scratches on the front lens but I won't buy one with scratches on the rear elements. Not only contrast is affected in this case but also resolution.

NB23 · Aug 15, 2020

AnselMortensen said:
I suggest trying it out in varying light conditions, particularly back-lit subjects.
I have a lens that had micro-pitting to the front element and had very low contrast and high flare...I tried a last-ditch, make-it-or-break-it "fix" recommended by a forum member that helped a lot, but don't want to share it unless your lens is completely unusable.

Why keep such a secret? Aren’t we supposed to share and care? I’d like to know what you did for sure

AnselMortensen · Aug 15, 2020

NB23 said:
Why keep such a secret? Aren’t we supposed to share and care? I’d like to know what you did for sure

OP should test first. Results might be acceptable. Drastic measure might not work on rear element, and could easily make things worse. If OP reports back with unacceptable test results, I'll be glad to share.

Dan Fromm · Aug 15, 2020

Testing was suggested on 8/1. No test results yet. I wonder why the OP hasn't tried the lens out. Its the only way to find out how well it shoots.

Donald Qualls · Aug 16, 2020

Dan Fromm said:
Testing was suggested on 8/1. No test results yet. I wonder why the OP hasn't tried the lens out. Its the only way to find out how well it shoots.

Not all of us can shoot film, get it processed, and scan/print in under two weeks. If you mail your film away, it might take longer than that just to get it processed, even if you shot the test the same day it was suggested.

Dan Fromm · Aug 16, 2020

Sort of true. But to see what I've got I just look at the neg/tranny. Scanning/printing is another opportunity to lose image quality.

Donald Qualls · Aug 16, 2020

Not everyone can see a negative well enough to compare lenses in that form. At the least, it requires more than even a 10x loupe and a reasonably even light source. Sure, you can tell if it's got huge field curvature or something gross, but not the kind of relatively subtle errors you'd get from a scratched or lightly pitted rear element.

AnselMortensen · Aug 16, 2020

And if you can't see it, then it's not a problem.

Donald Qualls · Aug 17, 2020

AnselMortensen said:
And if you can't see it, then it's not a problem.

Well, that depends if you only make contact prints, vs. enlarging or scanning your negatives.

Dan Fromm · Aug 17, 2020

Donald, when I look at negs and trannies I use a magnifier.

Replace, Keep, or Sayonara? 80mm Planar Rear Element

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