I have a Rokkor that I purchased used on this site a couple of years ago. I was told the rear element had some scratches in it. What I found was marks on both sides of the element...some of them quite deep. I tossed it in the closet and recently uncovered it when looking for some other items.
Do you think the lens has any value at all? Anyone know of a graveyard lens shop that might have an extra rear element? I know these go for ~500 in very good condition...do you think it would be worth ~$100 for parts?
Advice would be great...or I'll toss it back into the closet or trash...
Have you tried using it? You'd be surprised how badly glass needs to be damaged before it shows up in anything but the oddball situation. But, yes, I'd think you should have no trouble selling it for a hundred bucks.
When I purchased it I think the mirror would catch on the lens mount (1d2). Also it did not focus to infinity on my 30d... I'm not sure if these things are easily correctable...but if they are I'd like to keep it for my 5d. To answer your question it does work fine minus the above problems.
Use some East Indian ink to cover the marks and damaged spots with black. That's an old trick to "repair" lenses with dents and scratches. Your lens loses a negligible amount of it's light capturing capabilities, but the scratches can't cause diffusion and some of the aberrations related to uneven glass surface anymore. Just put some black in the scratch with something like a inkwriting pen and keep some absorbing paper at hand. After the ink dries in the scratches remove the rest of the ink that covers undamaged glass parts with the absorbing paper. Polish the glass carefully with microfiber cloth. You'll probably be able to see the black ink filling the scratches. If not completely covered do this again until your satisfied covering the scratches with black. This repair costs you practically nothing and your lens works "like new" although it doesn't show like.
godfather wrote:
When I purchased it I think the mirror would catch on the lens mount (1d2). Also it did not focus to infinity on my 30d... I'm not sure if these things are easily correctable...but if they are I'd like to keep it for my 5d. To answer your question it does work fine minus the above problems.
Dont know about the 5D but on the 5D2 infinity and mirror-hits can be a problem. One easy fix that potentially can solve both is filing down a portion of the upper part of the rear retainer ring. There's a recent thread here on that very subject.
I second EosFun's recommendation, black paint in the scratch will keep flares and stuff from showing easily. Set up a search on eBay for a "rear element Rokkor 58/1.2" and set it up to email you when one comes up.
I received a question via PM on the type of black ink. I mentioned Indian black ink since this is water resistant and it's made from pure carbon molecules suspended in distilled water. Real Indian ink does not contain gum arabic or shellack. Indian ink is water resistant and doesn't fade over time, it lasts for ages.
Here in the Netherlands it's in general being sold in shops that sell art-paint and drawing and sketching materials. I found this on-line fine art material shop by Google. I have no experience with them though. Most probably there is also some fine art material shop nearby in the city you live.
wfrank wrote:
Dont know about the 5D but on the 5D2 infinity and mirror-hits can be a problem. One easy fix that potentially can solve both is filing down a portion of the upper part of the rear retainer ring. There's a recent thread here on that very subject.
The 58/1.2 I recently bought off a forumer here had that exact modification, but under certain circumstances my 5Dc's mirror would still slightly catch the rear element when focusing to infinity. It's worth mentioning though that the EF mount has a bit of play. If I tighten that maybe the rear element would move away from the mirror just enough.
The vast majority of 5d (c & II) + Rokkor 58/1.2 will require both rear element retaining shave and mirror shave to avoid mirror collisions at infinity. This has been well known for several years now.
Some people have gotten very lucky with generous tolerances in the 5D (c & II) flange-to-focal-plane distance and only the reduction the the rear element retaining ring was needed. This has unfortunately given people the impression that their odds are good. This is not the case. In most situations, both rear element retaining shave and mirror shave are required.
The mirror shave is "big and scary" to many. Just think, I did this to a $4000 camera when it was 4 months old. It was a "no-brainer", and I was significantly intoxicated at the time. Surely anyone can do this on an "old POS" like the 5D now - - maybe even sober! (and yes, the same 5D that I mirror-modded is still going strong today)
If you want to see how I reduced the rear element retaining ring when I was doing conversions, check here: http://www.cogitech.ca/Rokkor/index.html Look at "Step 5".
P.S. Take some macro shots of the scratches and post them here for us to see. They have to be "really bad" to have any major impact on IQ.
And don't hold your breath on finding a rear element by itself. You'd need another lens to harvest parts from. NOS parts on an ancient minolta lens are not going to show up on ebay.
I want to thank everyone again for the responses. I took the above information and did some searches...
I set the infinity focus, cleaned everything, checked function on my new 5d, etc. Everything was good to go......
I had the rear element off to take pictures to show everyone and also to reduce the retaining.....F! F! F!
Long story short the rear element took a tumble and now has a massive chip on the perimeter . Lens is now officially F'ed. On a good note the scratches don't show up any more when staring at the chip....
Lens is now back in the closet and I'll casually watch ebay for a different lens. Is there a difference between the PC and the X version?
What really boils my blood is I'm not a hack when I go about fixing...always take my time and very methodical about it...not like me which really makes me mad.
godfather wrote:
I want to thank everyone again for the responses. I took the above information and did some searches...
I set the infinity focus, cleaned everything, checked function on my new 5d, etc. Everything was good to go......
I had the rear element off to take pictures to show everyone and also to reduce the retaining.....F! F! F!
Long story short the rear element took a tumble and now has a massive chip on the perimeter . Lens is now officially F'ed. On a good note the scratches don't show up any more when staring at the chip....
Lens is now back in the closet and I'll casually watch ebay for a different lens. Is there a difference between the PC and the X version?...Show more →
that sucks!
make sure you clean up the dust and glass chips properly if it was one of the radioactive ones (the rear element is the thoriated element in radioactive versions i believe).
Ouch! Sorry about your bad luck on this one and best of luck finding another (for a reasonable price).
sebboh wrote:
make sure you clean up the dust and glass chips properly if it was one of the radioactive ones (the rear element is the thoriated element in radioactive versions i believe).
I know for sure the thoriated element is in the rear group, but I am not quite certain if it is the actual rear-most element...
. Lens is now officially F'ed. On a good note the scratches don't show up any more when staring at the chip....