Jupiter 8 Collimation

[Dracotype]

Yes, I have a Jupiter 8, and it does take nice pictures, but the focus is way off. I need some instruction on collimation. If anybody has instructions, or pictures (even better), I would be most grateful.

Drew

 

[JonP]

Drew
Try this
http://www.pentax-manuals.com/repairs/j8service.pdf
It's a starting point, but as it says e-mail Kim!

 

[physiognomy]

Yes, I have a Jupiter 8, and it does take nice pictures, but the focus is way off. I need some instruction on collimation. If anybody has instructions, or pictures (even better), I would be most grateful.
Drew

I would join the Camera Collector board and ask Brian Sweeney... Here's the link:

The Camera Collector (click this)

Cheers!

Peter

 

[lkgroup]

I second the idea to contact Brian Sweeney... He did several Jupiter J-8's for me and a Jupiter 3. They we right on after he worked with them and are outstanding lenses to use.

Leo

 

[Nickfed]

You talk of - "Zorki 4 & Industrar 26m, Zorki 4 & Jupiter 8 "

Have you swapped Zorki 4s to ensure that the J8 is bad on both cameras?

 

[Dracotype]

You talk of - "Zorki 4 & Industrar 26m, Zorki 4 & Jupiter 8 "

Have you swapped Zorki 4s to ensure that the J8 is bad on both cameras?

Yes. I compared my J8 to my I26m(which I know is correct). I thought I had fixed it, but now it won't focus to infinity. I'll see what I can glean from Kim's paper. Keep the advice coming.

Drew

 

[Kim Coxon]

Hi,
I am on limited access at the moment through work as my internet at home is down. The most likely reason is either the helix is on the wrong thread (mt assembly instructions should help) or the shimming is wrong. Make sure the helix is right and if that doesn't cure it, get back to me.

Kim

 

[Spyderman]

First let's split the problem into 2 smaller problems: the focussing block, and the optical block. So start by unscrewing the optical block from the focussing block.

Then make sure, the focussing block focusses right - with a known good calibrated rangefinder, the focussed distance on scale equals the distance at which the rangefinder images coincide. To do this follow the pdf manual. You might need to find the right thread start.

Only then start with collimation. Using the 2 cameras collimation method add or remove shims between the focussing and optical block. This way you have the lens collimated at infinity. This should be enough. If the focus is still off at close distances - ask Kim what to do 😀 But you would perhaps need to add shims under the rear lens group of the optical block (the rear group unscrews easily).

And let us know about the results...