TiMo
I have a lens that’s gone mouldy on the inside, and I don’t really need it anyway – or rather, I could get one in better condition for a bargain price. So I decided to take it apart and have a bit of a experiment.
I’ve taken the thing apart as far as I can. I just can’t reach the spot where the mould is. I’ve already looked for exploded diagrams of the lens, but haven’t found anything. Similar lenses differ precisely at the point where I’m stuck.
I suspect I can unscrew the front section. However, I haven’t made any progress with the rubber cone; no matter where I tried to start. It’s also quite possible, of course, that the screw connection is very tight.
If anyone has experience with this, I’d appreciate some tips.
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AchimBauer
Konban wa, Timo,
I don’t know much about this lens either, but I’m one of those people who likes to take old bits of kit apart just for fun and to see how they work.
That’s why I reckon that what you’re calling the rubber cone in the first picture would have two fine slits if it were designed to be screwed on. I suspect that it wasn’t designed to be opened at all, and that the cone is pressed in, and can only be removed with a special trick, if at all. If it weren’t precision engineering and there weren’t the risk of the resin holding the lenses in place melting, I’d do what you do with engine parts and put it in the oven so that the metal expands and the cone falls out. Here, the best you could do is try to get a fine tool between the cone and the metal and then run a second tool all the way round, much like when changing a tyre.
But remote diagnosis is always difficult.
Go-kigen`yo Achim
TiMo
Hi Achim,
By ‘rubber cone’, I meant a tool. You can use it to loosen screw connections by pressing the cone onto the ring – the one you often find at the front of lenses – and turning it.
I find it hard to believe that the lens is stuck fast. They didn’t make such rubbish back in the day.
Best regards,
Tim
AchimBauer
Hi Tim,
Lenses have been glued together for a long time. In the past, this was done using resin – a substance similar to what’s used in microscopy to embed specimens. That’s usually where the fungus lives, too, as it can’t survive on air and love alone.
The bonding is a design requirement when two glass lenses need to be mounted together. That doesn’t mean, however, that all lenses are bonded.
Regards, Achim
TiMo
Hi Achim,
I misunderstood you there. I wasn’t referring to the lenses themselves, but to the housing. I’m quite sure it can be opened further. I just don’t know exactly where. On the front, in the ribbed section, you can see three places where there’s a step. You can definitely open it at one of those points.
Cheers, Tim
AchimBauer
Hi Tim,
So, when I look at the photo of the front, I can see a dot at the top and I’m not sure what it is. It could be an empty thread, but there might still be something inside. If there’s something in there, unscrew it – it could be an anti-rotation device that stops the shiny grey ring from being unscrewed. I had something like that on the lens of a broken CCTV camera I’d picked up from the scrap heap, which I wanted to use for a DIY project.
If that’s not it, I’d try the first matt black ring.
If the lens is no longer needed, I’d eventually reach the point where I’d resort to harder measures, like spray? (with a lens, you’re more likely to do more harm than good) or heavy-duty tools, sawing slots for screws, etc., to gain experience for other situations.
But if the parts are really screwed on and not pressed in – you never know what they came up with to save money – it should work.
Perhaps try giving the rubber cone a few sharp jerks if the thread has seized up. After the first few jerks, it often turns more easily.
Regards, Achim
Wolfgg
Most fixed-focal-length lenses consist of two lens mounts: one in front of the aperture (and the shutter in the case of a central-shutter lens) and one behind it. Designers do not want any visible screws at the front; this is usually achieved by means of a rotating cover ring (the black pseudo-lens hood). In this case, cut out a suitable rubber ring, ideally from shoe sole rubber (which is very grippy), place it on the plastic ring, find something round with roughly the same diameter to use for turning (a suitable bottle cap, piece of tube, etc.) and turn it in the opposite direction to the clockwise direction. Be aware of any locking screw on the focus ring; it may also be hidden under the rubber grip on the focus ring.
Regards, Wolfgang
Commander8x
Hi,
I had mine cleaned at a garage.
I found these whilst browsing (though they’re mostly for the f/2.8 version):
http://akikorhonen.org/projects.php?action=view&id=774
http://www.jedi.com/obiwan/photo/nikon55-28.html
http://rick_oleson.tripod.com/index-102.html
http://conradhoffman.com/MicroNikkor55.html
The last image here looks as though the ring on the front has been screwed on from the front?
And here ( http://photo.net/nikon-camera-forum/00Fg74 ) it says:
"unscrewing the lens mounting ring was the way to go"
Good luck, Matthias
TiMo
Thanks for the links, Matthias. Unfortunately, the 2.8 model is built differently to mine. It’s not worth repairing, as I could buy the lens twice over for the same price.
However, I’ve managed to sort it out now. It was relatively easy once I stopped placing the rubber plug on the flat front surface and instead positioned it slightly further inwards, where the material is matt. The friction is higher there.
In the second photo, you can see the element turned upside down and unscrewed further apart.
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PS:
@ Wolfgang: I have rubber cones in various diameters. They can be seen in the first photo. They usually work quite well.
@ Achim: The hole is from a screw; however, it serves as a stop for an outer ring, which has already been removed here.
