Lens Repair

MartinCrabtree · Apr 8, 2017

I recently purchased a Nikon 25-50 f4 Ais. It won't focus to ∞,the distance in the scale is wrong,focus changes when zoomed(normal?) and there's a rattle/clunk when tilted up or down. I had a guy who took care of my lenses but he quoted a very high price and I'd like to try someone else. Posted here 'cause I don't know where else to do so. Otherwise it's in great shape and I want to get it repaired.

Nodda Duma · Apr 9, 2017

Return it and get another that's not been taken apart and had who-knows-what done to it?

MartinCrabtree · Apr 9, 2017

That's not an answer to my question. Care to help?

Nodda Duma · Apr 9, 2017

That is an answer, I'm sorry you don't consider it as such. It would be less expensive than getting it repaired. It's what I would do.

Otherwise, can't help you.

Theo Sulphate · Apr 9, 2017

It's a somewhat rare lens and desirable for its range (I have its somewhat less desirable little sister, the 28-45/4.5 AI).

If you like that particular lens, I'd say maybe it's worth having your repair guy work on it, even though the quote is high.

Having it change focus when zoomed may not be an issue (varifocal lens?). But clearly someone has had it apart for some reason and misaligned the focus ring.

shutterfinger · Apr 9, 2017

There is a service manual for the Auto Focus f3.5-4.5 version at http://arcticwolfs.net/
No clue if the designs are similar or not.

Leigh B · Apr 9, 2017

MartinCrabtree said:
... and there's a rattle/clunk when tilted up or down.
I had a guy who took care of my lenses but he quoted a very high price and I'd like to try someone else.

You probably got an accurate estimate. I suspect it would be cheaper to buy a replacement.
KEH has one in EXC condition for $257. That's about half of what I would charge.

I repair lenses, but I would not touch one with a loose internal part for any amount of money.

Most likely a lens element came unglued from another element due to a shock or similar event.
There's no way in hades I'd attempt to correct that.

- Leigh

MartinCrabtree · Apr 11, 2017

I somehow expected more from this forum. Thanks anyways.

Leigh B · Apr 11, 2017

MartinCrabtree said:
I somehow expected more from this forum. Thanks anyways.

It's a bummer when reality doesn't meet your expectations.

- Leigh

MartinCrabtree · Apr 11, 2017

Sarcasm is the hallmark of a man with nothing worthwhile to say.

Dan Fromm · Apr 11, 2017

MartinCrabtree said:
Sarcasm is the hallmark of a man with nothing worthwhile to say.

Et tu, Brute.

John Koehrer · Apr 12, 2017

Zooms have a couple of commonish problems. The loose element that's been mentioned and/or a broken
roller or shaft.

Just for giggles, if you put a finger on an element; front & rear separately & shake it does it still rattle?

Noemi · Apr 12, 2017

No idea if he can help your specific issue with lens, but I just had a Yashica 124 G CLA'ed and brought back to life by Dave, at a very reasonable price. He repairs all kinds of cameras.
Worth asking him: dave@davescamera.net

MartinCrabtree · Apr 24, 2017

John Koehrer said:
Just for giggles, if you put a finger on an element; front & rear separately & shake it does it still rattle?

If I press lightly on the front element it stops. Does that tell you something?

~andi · Apr 24, 2017

Martin, did you try Nikon customer service directly? It may be worth a try. Going to the manufacturer is not necessarily the most expensive route.

flavio81 · Apr 24, 2017

MartinCrabtree said:
I recently purchased a Nikon 25-50 f4 Ais. It won't focus to ∞,the distance in the scale is wrong,focus changes when zoomed(normal?) and there's a rattle/clunk when tilted up or down. I had a guy who took care of my lenses but he quoted a very high price and I'd like to try someone else. Posted here 'cause I don't know where else to do so. Otherwise it's in great shape and I want to get it repaired.

Martin,

This is a common problem with old zooms. The moving groups inside the lens ride on a 'zoom cam'. The mechanics which 'ride' there can wear and/or develop slack, which makes those inner groups "rattle". This also means that the precise position of each group isn't mantained anymore.

The consequence is that the zoom is no longer able to keep the focus point while zooming.

Yet another side effect is that the infinity stop will be wrong and, of course, that focus scale won't tell the real distance.

You need a technician to open up the lens and inspect if the little pins that ride on the zoom cam can be renewed/repaired/etc so slack is gone. This should automatically fix all the other problems.

@Nodda Duma i'm surprised you did not comment furhter on this topic.

Dan Fromm · Apr 24, 2017

MartinCrabtree said:
If I press lightly on the front element it stops. Does that tell you something?

Yes. It tells me that the lens has been taken apart and reassembled badly, as was mentioned in post #2 above.

Give up on it. Try to get your money back from the seller. And then buy another one. Or pay Nikon to fix it, if they'll take it on.

Nodda Duma · Apr 25, 2017

flavio81 said:
@Nodda Duma i'm surprised you did not comment furhter on this topic.

I provided my advice. Signs of being previously disassembled and then dumped on the market usually end up as a lesson in cost of time exceeding cost of material. I've fixed plenty of optical assemblies in the past (both on the production line and at home), but never enjoyed buying someone else's problems. I would have returned it and bought another.

dmr · Apr 25, 2017

MartinCrabtree said:
I somehow expected more from this forum. Thanks anyways.

I would be interested in this too. Are there any reasonably-priced lens repair services out there at all? (LOL, well-kept secret?)

I have two K mount lenses that need some minor adjustment, one of them just is off focus at infinity. The local camera shop can send them somewhere and they will work them over for about $250.00 each, which is roughly 2-3 times the street price of replacements.

Dan Fromm · Apr 25, 2017

dmr said:
I have two K mount lenses that need some minor adjustment, one of them just is off focus at infinity. The local camera shop can send them somewhere and they will work them over for about $250.00 each, which is roughly 2-3 times the street price of replacements.

There's a hint. Take it.

flavio81 · Apr 25, 2017

dmr said:
I would be interested in this too. Are there any reasonably-priced lens repair services out there at all? (LOL, well-kept secret?)

I have two K mount lenses that need some minor adjustment, one of them just is off focus at infinity. The local camera shop can send them somewhere and they will work them over for about $250.00 each, which is roughly 2-3 times the street price of replacements.

Adjusting infinity stop is trivial. $250USD for each is theft.

flavio81 · Apr 25, 2017

Nodda Duma said:
I provided my advice. Signs of being previously disassembled and then dumped on the market usually end up as a lesson in cost of time exceeding cost of material. I've fixed plenty of optical assemblies in the past (both on the production line and at home), but never enjoyed buying someone else's problems. I would have returned it and bought another.

What i mean is that it might not be caused by tampering with the lens internals, but simple aging.

Many early 80s canon FD zooms can suffer this problem. The moving groups ride the zoom cam using a nylon bearing that rots/destroys with the passage of time. Such a lens will rattle, lose parfocality, and have wrong infinity stop. All this without anyone dissasembling the lens.

Such a lens ought to be repaired, not discarded.

Here i speak from direct experience with two canon Fd 35-105/3.5, and a canon fd 35-70/4 with exactly the same symptoms and causes of said symptoms.

Leigh B · Apr 25, 2017

dmr said:
...they will work them over for about $250.00 each...

That's certainly less than I would charge.

But is the problem really the lenses? Awfully odd to have two with the same issue.

Could it be that the camera is damaged, with the lens mount being bent or displaced?

- Leigh

Leigh B · Apr 25, 2017

flavio81 said:
Adjusting infinity stop is trivial. $250USD for each is theft.

Without actually knowing what the problem is, your statement is nonsense.

- Leigh

John Koehrer · Apr 25, 2017

No. $250.00 is nonsense. If you're getting more, there should be picture of you on the post office wall.

Lens Repair

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