jdedmonds

I have had an 85mm f/1.4 Nikon lens for many years. On the rear element is a tiny deposit (not a divot), maybe 1mm across, that I am unable to remove with any safe solvent. I can see the defect through the wide open lens through the front element but am not sure it affects images. I want to send it to Nikon or somebody else to have the rear element coating redone. Is this possible? Anyone know how much it costs and who can do it? Thanks for any help.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

You would get definitive and accurate answers to those questions if you asked NikonUSA.

LFingar Loc: Claverack, NY

First, take a bunch of test shots of different scenes under different conditions and see if it is actually detectable in your photos. If not, I wouldn't worry about it. If it is detectable in your shots, or if it just bothers you enough knowing it is there, I would contact Nikon. If it can be repaired you know they will do it right, although, you may find it isn't worth the price.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

Recoating a lens element is possible but not practical. The coating is not removed by a solvent, it must be polished off and this process may change the characteristics of the lens element. Coatings are applied at an elevated temperature in a vacuum so it's not something that a repair facility would do. The lens would probably have to go back to a Nikon manufacturing facility and the cost probably wouldn't be worth it in the long run.

Notorious T.O.D. Loc: Harrisburg, North Carolina

dcampbell52 Loc: Clearwater Fl

The lens is a decent lens and possibly worth refurb depending on cost. I agree with Mac and contact NikonUSA for pricing of the refurb. Then, I would compare that price with the cost of a new lens and any upgrades it might have. Even if (down the road) you decided to upgrade to the newer lens, you would have the refurbished as a backup or to use on a second camera body (either FX or DX).

cthahn

Consider another lens.

olsonsview

If the spot does not affect images, then forget about it. If it does affect the final image then what solvents have you tried? I have used Xylene to remove gunk with no damage to coatings, but go slowly and gently, and under good ventilation, preferably outdoors. Hospital cotton swabs, and one pass then replace with another swab. No scrubbing action at all, no real pressure. Just dampen with solvent on the offending area and gently pass the swab over it again only hard enough to loosen the crud, also rotate the swab so a clean part of the swab makes contact every cleaning pass, replace them often. After that harsh cleaning do a normal lens cleaning solution then a bit of distilled water to finish up. I would only do that if the lens were indeed needing it, and there was no alternative. In that case the lens is junk, and in the worst case: if you destroy it then just buy a new one. Before an outcry is heard I have done this on maybe ten lenses, never lost one! I have collected/repaired used microscopes for years, and the objectives can often be found compromised by gunk.

jerryc41 Loc: Catskill Mts of NY

Repair might not be necessary.

http://photographylife.com/what-to-do-with-dust-inside-lens
http://kurtmunger.com/dirty_lens_articleid35.html
http://www.lensrentals.com/blog/2008/10/front-element-scratches

amfoto1 Loc: San Jose, Calif. USA

Is it possible to have recoated... yes.

Is it practical... no. It would cost far more to have the old coatings removed without changing the very precise shape of the element or destroying it entirely, then many additional dollars would be needed to have custom-made coatings properly reapplied. All told, it would end up costing far, far more than the lens is worth.... probably thousands or tens of thousands of dollars. (When lenses are made, manufacturers apply coatings to large number of elements in batches, before assembly, to keep the cost per unit reasonable.)

It is much more practical to simply replace the rear element (or rear group of elements, if they're assembled in a way that's impractical to disassemble).

If the lens is still in production, Nikon or one of their 20 or so authorized repairers (if you are in the U.S.) can probably replace the parts for you. You'll have to ask them what's possible and what it might cost.

If the lens is an older model that's no longer in production and necessary replacement parts are no longer available, an independent repairer might be able to fix it... if they can find a good, used part from a donor lens.

Either way, the repairer will re-calibrate the lens after the repair. They likely would do a cleaning and lubrication as part of the process, too. And they may replace other parts that show excessive wear.

Have you shot with the lens? That spot may not have little or no effect on images. Now, damage or spots on a rear element are often more problematic than on front elements or on surfaces inside a lens. But

Reinaldokool Loc: San Rafael, CA

I have used Criscam in Arizona to repair cameras and lenses on several occasions. They will give you instructions to send it to them, then give you a cost estimate to fix the problem. They are authorized repair for a lot of camera companies like Nikon and Canon. Good people to work with.

DJO

You didn't specify the lens as AF or Ai. Regardless, the 85/1.4 always has been and always will be an expensive lens. This is a suggestion: shop used for the ugliest one you can find, or better yet one that is being sold for parts. Buy it and swap the rear elements. You can then sell it again for parts, or as a complete lens in less than perfect condition.

Yes this will require some time and effort, but may possibly be your lowest priced solution.

I have done this, although with a less expensive lens, and my net cost was was next to nothing.

Good luck to you.

rmalarz Loc: Tempe, Arizona

Spots and scratches on the front element seem to have little affect on images. The rear element is a different story. I'd contact Nikon and see what they say. That's a great lens and worth having, especially in pristine condition. I'd definitely check with Nikon prior to making any decisions. They may be able to simply replace the rear element and be done with it.
--Bob

Dabe Loc: Southern Missouri, Ozarks

jdedmonds, I'm curious as to what types of "safe solvents" you have tried, and specifically what solvents you consider safe? I would almost bet there is a solvent which would take this deposit right off, and at the same time be harmless to both the optical coating and the glass. Obviously you would want to be careful with certain solvents, and keep them isolated to the glass itself, but there is almost assuredly a "safe solvent" that would remove your problem deposit while causing no harm to your optics. The concern I would have is that the deposit itself may be detrimental to your lens coating, and possibly to the glass itself depending upon its chemistry and how long it is allowed to remain on the lens. Glass lenses and most optical coatings are tougher than most people realize, but strong acids and alkalies should definitely be avoided. If you had any idea what type of contaminant you're dealing with, it would be instrumental in knowing exactly what to clean it with. As an example, a sugary deposit may be immune to both alcohols and petroleum solvents, while a little distilled water on a lens cloth will take it right off. You could most likely save yourself a good deal of unnecessary expense by taking care of this yourself.

dsmeltz Loc: Philadelphia

Or take test shots of a blue sky or indoors of a piece of paper so you have a single color filling the frame. Turn off AF and take a few shots at different focus settings. If the lens is having a negative effect, you should be able to see it. Ignore specks that are probably dust on the sensor. Something on the rear element will probably show up as a blob. My guess though, is that it is not having much of an effect on images.