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10-06-2013, 08:24 PM   #1
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Did you ever disassemble a lens to clean it?

How did that work out for you? Did the lens get clean, and were you able to reassemble it so that it functioned again? Did the cleaning help? Thanks. Glenn

10-06-2013, 08:35 PM   #2
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It is fairly easy with old manual primes, very simple designs and less moving parts than a zoom.
10-06-2013, 08:42 PM   #3
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QuoteOriginally posted by elliott Quote
It is fairly easy with old manual primes, very simple designs and less moving parts than a zoom.
Thanks, elliott. I see an F 70-210 on ebay with bidding starting at $50. I have seen excellent photos taken by this model of lens and it has a good rating here on PF. The price seemed reasonable, but the poster clearly notes that there is a hair internally and some particles. I'm not bad (but not great either) at handy work. I bet I could get it apart and cleaned, but how in the world could I put it back together and have the parts all line up correctly? Just throwing away $50? The poster says that the hair does not hurt photos currently.
10-06-2013, 09:05 PM   #4
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I have taken apart and cleaned a number of older primes mostly Takumars which are fairly easy. I would not attempt an auto-focus zoom lens. I would sent it in to Eric or CRIS for cleaning rather than attempt it myself. But that's just me. And my eyes are no longer up to close work.

The F 70-210 is a very good lens, I have taken a number of very good images with it. It is very heavy and since I got the DA*60-250 I don't think I've used it much. Note there is also a Takumar F 70-210 which is not supposed to be as good. Make sure the one you are looking at has red lettering.

Also note that there are F 70-210's on ebay almost all the time so don't get into a bidding war, another one will be available. You can get a used DAL 55-300 for $180 - 200 so you have to be careful what you pay for the 70-210.

10-06-2013, 09:34 PM   #5
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The F 70-210 is a little bit trickier to take apart than other similar F series lens.

Also, as with all A series lens and forward, if you take the mounting flange off, there are many small parts that are spring loaded, easily lost and very fiddly to put back together again.

I would suggest that you gain some experience first on more simple lens design, such as the M50/1.7.
10-07-2013, 05:02 AM   #6
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It's not that difficult with the older lenses. M42 series lenses, especially presets, seem to be the easiest if you want to get some experience first. They usually come apart very easily and are easy to clean. As you progress up through the different lens series the insides tend to get more complicated, and as Tom pointed out there are lots of very small parts that can be very difficult to put back together, and once you get into auto focus lenses you end up with electrical contacts that can be very fragile. Zoom lenses present a whole host of other issues, and while getting them apart might not be an issue, getting them back together so that they work properly can be. Also one other word of caution, I assumed you were referencing Pentax, but if not I have found out that some older third party lens makers, such as Sigma, had a tendency to permanently glue some some of the insides of the lens together, making it extremely hard to even disassemble them.
10-07-2013, 05:58 AM   #7
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I've disassembled a few M42 lenses, those are usually quite save to take apart because there are now spring loaded parts flying at you...

QuoteOriginally posted by tom1803 Quote
The F 70-210 is a little bit trickier to take apart than other similar F series lens.
Can the seller tell you where inside the lens the hair is? The front lens group of the F70-210 can be unscrewed from the front quite easily.

Anything else would probably not be worth the risk, this might give you an idea of what to expect:
Pentax 70-210 Repair

regards
Jan
10-07-2013, 09:37 AM   #8
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QuoteOriginally posted by tom1803 Quote
The F 70-210 is a little bit trickier to take apart than other similar F series lens.

Also, as with all A series lens and forward, if you take the mounting flange off, there are many small parts that are spring loaded, easily lost and very fiddly to put back together again.
Here's a photo of the F70-210, ready to put the mount back on. The mount has individual plastic insulators for each contact. Other lenses are made so it's much easier to align all these contacts, springs and insulators as a group, but this lens takes a lot of patience to get all the loose parts in place.




The front lens group does come off easily. You could possibly avoid taking off the mount by removing only the light shield, a plastic part inside the mount that closes the gap between mount and the rear lens element. The rear lens group can probably be unscrewed with the light shield out of the way. The hair is probably between the inner element of one of these groups and the aperture blades.

I think $50 is kind of high. I just sold one of these for $50 with some light scratches on the outer edge of the front element. I'll sell you one with element separation for $40.




10-07-2013, 11:00 AM   #9
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Thanks for the repliesd - all good. I believe the hair is just inside the front element, if I recall correctly. I have my 55-300 and it has been good, just thought I might try something else that is good and cheap. I believe I'll forego the ebay item, based on the replies.

Regards,

Glenn
10-07-2013, 02:53 PM   #10
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I've disassembled a couple Nikon 18-200 VR lenses all the way down to clean and replace an AF motor. Takes a lot of patience but was worth it in the end. If you can get it for a really good deal and feel like a challenge, i say give it a go. Just don't remove the front lens. I've heard it has to get sent to a shop for re-alignment if you do that.
10-08-2013, 09:45 AM   #11
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QuoteOriginally posted by GlennG Quote
How did that work out for you? Did the lens get clean, and were you able to reassemble it so that it functioned again? Did the cleaning help? Thanks. Glenn
I just disassembled a older Sigma 50mm f2.8 manual focus macro lens and cleaned it. It was not the first lens I have taken apart but by far the most challenging. It has a floating rear lens that moves with the front element and you have to get it just right when putting it back together. I had to take it back apart a couple of time to get it right but it works great now. Just take your time and remember how you took it apart.
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