Tutorial: how to open and clean a Nikkor 105/2.5 AiS...

[tomasg]

...and to put it back again of course

Some time ago i got this lens from Attila, it just had a few hair like fungi, (i guess?), on the rear element, no influence on image quality, but the lens was quite dirty inside also so...here it goes:

1 Set the aperture to f22, turn the lens to the closest focus position, this will give you acess to the 3 screws you need to remove, side note: i had to drill out one of the screws it was too stuck to get out






2 Unscrew (Counter Clock Wise) the complete front part, where the hood is, it will maybe need some force the first time



3 Simply gently pull up the complete lens assembly


4 Unscrew the front group CCW, in my case it was enough to clean the last element in the group, so i didn t need to open it up further, it looks well sealed, but i think it can be opened if needed




5 The rear group can be opened for easyer acess, it s where my lens had fungi, simply unscrew the last part of it


6 Just in case, if the ring that commands the aperture falls out, that s the correct position, if it falls out be careful, there a less then 1 mm »stair« around the aperture hole, the ring must fit perfectly in it, otherwise you won t be able to screw back the rear group



7 As the front group, the rear one can probbably be opened (look at the screw), again in my case it was not needed, i managed to clean the »fungi« that was inside...


8 Ok, back it goes...first screw back on the rear group, make sure the ring for the aperture is in it s correct place, screw all the way down, ckeck if the mechanism for the aperture works fine.
Screw back the front group, nothing too difficlt here...




9 Now the tricky part...putting back the lens group back into his helicoid. Make sure the aperture is still set on f22, both on the helicoid (lens aperture ring) and on the aperture mechanism...

10 This one...wich i will call the MALE


11 Wants to meet this one, the FEMALE, they really love each other



12 Now with the MALE, close down again the aperture mechanism (not the aperture ring on the helicoid), BUT then reopen it JUST a bit, with my lens i had to allign the Male to the »red« screw, look at the two pics, first closed all the way down than alligned , simply you have to open up the aperture mechanism, this may vary (or not be necessary at all!), in my case i moved it 2 mm or so.




13 Now that you ve done that and the aperture on the helicoid is set to f22 look at this slot in the picture


14 ...you have to allign this screw into the slot


15 Put the lens group into the helicoid, alligning the screw to the slot BEFORE putting it in, don t turn it once inside, slowly lover the lens group, if you find the right position of the MALE everything will go in place all the way down. When this happens, turn SLOWLY, gently, the aperture ring on the helicoid, if you got it right it will open it up. This may recquire some trials before finding out the position for the MALE to match the FEMALE


16 Screw back the front part that holds the hood, if you look close at the end you ll be able to see the marks that where left by the 3 tiny screws, this way you can reposition the whole lens group exactly where it was...i tighten it a bit more, i think it doesn t make any difference, as the whole group moves together. Put back the 3 tiny screws and you re done!

ok...i hope it s not been already done by someone else

i opened and cleaned my Vivitar 85/1.8, my Tair 11a and my Nikkor Micro 55/3.5!
if there is some interest in those lenses i can reopen them and make a similar tutorial

best regards

tomas

[Attila]

Thank you for your excellent tutorial , a bit sad to see this lens in parts

[indianadinos]

Hi,

Thanks for sharing your great tutorial ...

Cheers

[Himself]

Excellent, neat job!
Well documented!

[martyn_bannister]

I know how long it takes to describe (and take such quality shots) of this sort of process. Many thanks for posting a valuable resource. Perhaps we should set up a database of this and similar?

The screw you had to drill out. Where did you get a replacement? Do you or anyone else know what sizes are the norm in lenses and where they can be bought from? It is common to have to do this, as well as losing screws in the carpet

[tomasg]

Well, i had to drill just one of the 3 screws (the last one), wich function is to prevent the unscrewing of the front part of the lens, i put back the other two, but even without them the front part is securly enough screwed on.

As for the spare screws...i have no idea where to order them, i guess if one does a search on the net they can be bought. There s still a watch repairman in the city i live in, i guess he can be a good supplay...

tomas

[martyn_bannister]

[ks73]

This guide is excellent! I managed to clean fungus spots from my copy.

[tomasg]

[56 DIN]

thanks a lot for the time you spend to show us how to do
at the moment my 2.5 105´s are clean, but who knows

small screws you get from opticiens or wrecking old cams/lenses

[kds315*]

[nikonpinoy]

Thank you for making this guide. I was able to clean my lens.

[tomasg]

Nice to see that it s still useful for someonne after so much time.

[Eddie46]

Those mini-grub screws are a pain on many lenses.They appear to have been 'set in' with paint or lacquer.I had some success on a Chinon lens using a tiny drop of nail varnish remover dropped of the end of a (Wooden) cocktail stick so as to minimise damage to surrounding paintwork.Leave it for a minute or two to do its work.

[tomasg]

On the Nikkors i had CLA-ed and had glue in various parts of the construction i was able to remove it with dimetil alcohol.