Baybers
Established
Yesterday I unscrewed the optical block from my 1959 J-8. I sprayed a little 91% alcohol into the rear of the helical block to loosen up the focus. This worked. I did not touch any screws or attempt to take apart.
After that I screwed the optical block back in with the two shims in place and made sure it was seated properly.
I went to shoot and found that now the aperture ring closed down turns past the f22 mark and will only turn the other way to approx. f2.8 - photos attached.
The aperture itself is working correctly, opening and closing without any problem.
The focus ring stops at infinity but turns to below the 1 Meter mark on the scale. Not sure if it did this previously.
What have I done?
After that I screwed the optical block back in with the two shims in place and made sure it was seated properly.
I went to shoot and found that now the aperture ring closed down turns past the f22 mark and will only turn the other way to approx. f2.8 - photos attached.
The aperture itself is working correctly, opening and closing without any problem.
The focus ring stops at infinity but turns to below the 1 Meter mark on the scale. Not sure if it did this previously.
What have I done?
Attachments
nhchen
Nathan
Hi Baybers,
I've taken apart a few of these lenses and I think the only thing you have to do is screw the optical block back in even tighter to align the aperture mark of f2 to the correct position. This is probably important since if it is not screwed correctly the lens-film distance is slightly off too. Just get pieces of rubber to help you grip. Hopefully that works. I wouldn't worry about the focusing, it sounds like what they usually do.
regards,
nathan
I've taken apart a few of these lenses and I think the only thing you have to do is screw the optical block back in even tighter to align the aperture mark of f2 to the correct position. This is probably important since if it is not screwed correctly the lens-film distance is slightly off too. Just get pieces of rubber to help you grip. Hopefully that works. I wouldn't worry about the focusing, it sounds like what they usually do.
regards,
nathan
Baybers
Established
Still Fummoxed
Still Fummoxed
Thanks for the reply Nathan.
I have tried what you suggest and I still cannot get them to align. The optical block was very tight when I unscrewed it and I'm wondering if in doing that something moved inside. Is it possible for the internal mount to move inside the shell of the lens? Not having taken one apart I have no idea.
Still Fummoxed
Thanks for the reply Nathan.
I have tried what you suggest and I still cannot get them to align. The optical block was very tight when I unscrewed it and I'm wondering if in doing that something moved inside. Is it possible for the internal mount to move inside the shell of the lens? Not having taken one apart I have no idea.
WJJ3
Well-known
I would reference this if you haven't already.
I have an early '60s copy that looks like the same as yours that I overhauled using that guide. It all went smooth, but I found that I had to adjust the position of the F-stop ring to match the aperture range when I was done cleaning and lubing everything. It's not hard to do, and I suggest you do the same.
I would definitely avoid trying to tighten the optical block down enough to get it to mach the position of the ring. It was probably over-tightened before you unscrewed it. Mine was.
Once I got everything put back together and adjusted I tested focus on my M3 and it was fine.
Best.