jupiter 9 stiff focus

[rs1]

Hello all,<br>

<p>Got me a Jupiter 9, serial 61xxxx. Works good but focus is a

stiff son'btch. Will it get easier after use or will I have to open

it up and regrease? I wanted to avoid getting into the lens as I

have heard it's a complicated one to put back together. Kiev

survival site has it all explained, yet I hesitate.</p>

It's a good lens, pictures are coming out well.<br>

Advice will be appreciated.<br>

Here are some photos from a few of days back.<br>

<img src="http://members.shaw.ca/rajivsankranti/img920.jpg"><div></div>

[rainer_t]

Hi Rajiv,

 

it was the same with my Jupiter 9. I sat down for about 30 minutes

and turned the fokusring from one end to the other continously.

Since then I never had this problem again.

 

Rainer

[luis triguez]

Rajiv,

 

Have you tried to put, carefully, some white lithium grease with a little cotton stick �those for baby ears- around the focusing ring?. I did with an old Canon Serenar and worked perfectly.

[rs1]

Rainer, Luis,<br>

<p>Thanks for the suggestions. I have been working it and it is a little better but still stiff at close focus end. Thanks for the Lithium grease suggestion, I am going to buy some today. Don't have any at home right now or I would have tried it right away. I guess I could apply a little on the exposed part of the barrel and then let it slide over and pick up the grease.</p>

[nickc1]

I have one in LTM and one in Kiev, and so far both are OK, but this may help if you decide to take it apart. Experience with other lenses suggests that the problem is unlikely to be too little grease, but rather old grease that has gone stiff - the only long term answer is probably to take the thing apart, clean all the old grease off and regrease. FSU lenses did't get the most modern of lubricants, even when new, and the difference that a proper clean and lithium grease makes is fantastic - the quality of the underlying engineering shows through the appalling quality control - they become a treat to use.

 

http://www.pentax-manuals.com/repairs/j9service.pdf

 

Nick

[kelly_flanigan1]

A stiff J-9 is a good thing. It means it has not been messed with. It means you have a better chance 1 in 3 that it will actually focus ok.!

[rs1]

Nick,<br>

Thanks for that link. I think I am going to get a hard copy of that document... :-)<br>

Kelly, I guess I was lucky at russian roulette this time round. It seems to focus well at the wider apertures too. I haven't taken anything at f2 as yet but f2.8 seems to work alright.

[Dustin McAmera]

I bought one which stiffened rapidly in the first few months I had it. I read a few things that said 'warm gently and exercise the focus'. This worked as long as the thing stayed warm, but overall the stiffness got worse until the lens became unusable. I sent it away to be relubricated, but got the same experience as when I'd just bought it. It was ok in the shop, but got worse very soon. In the end, I bought another that wasn't so old, or so bad. The new one is stiff too, but consistently so - it hasn't changed since I got it.

[winfried_buechsenschuetz1]

If it is a LTM (M39) J9 disassembly will be quite different from that method shown on the Kiev page. You should mark the initial and the come-off position of all threads and helicoids. The problem with the LTM version is that it has two helicoids coupled by a pin and a slot. Both helicoids are rather tight, and you should use very light grease to lubricate them. I tried with my usual silicone grease and the focus action was much too stiff, I had to remove it completely again and replaced it by graphite powder (very little) and silicone oil.

 

Another problem is that there is only one coupling pin/slot between the two helicoids. There is a lot of pressure and hence friction between the pin and the slot, and the pressure on the second helicoid is applied off-center, so there will always be a lot of friction. But this is a design issue and cannot be cured. You can try to put some molycote paste on the pin/slot coupling.

[rs1]

Winfried,<br>

My J-9 is the Kiev mount one so hopefully without those problems that you described for the LTM.