Jupiter 8 question

pesphoto

pesphoto

Veteran
Local time
10:06 AM
Joined
Oct 28, 2005
Messages
3,894
I recently acquired a J8 and think it may have a problem, but being that its my first Russian lens Im not sure. When I turn the aperture ring, the focus ring turns and vice versa. Can anyone shed some light for me?
 
Sounds rather badly seized. Time to disassemble and clean out the old grease. Is it a chrome J8 by any chance?

Peter
 
That's the way it is designed to work. It's a little inconvenient, but that's the way it is. There may be different versions of this lens that doesn't, but mine does.
 
Its a black J8. Frank, its normal? Seems like it could be inconvenient to use. I guess I'll give it a try.
 
As long as they turn independently if you hold the other. Kind of strange, but Frank is right. I find it better to use the J8 with an unmetered camera where I set the exposure prior to bringing the camera to my eye.
 
rover said:
As long as they turn independently if you hold the other. Kind of strange, but Frank is right. I find it better to use the J8 with an unmetered camera where I set the exposure prior to bringing the camera to my eye.
Click to expand...

Thanks Rover for confirming it for me. I'll have to check when I get home if they turn independantly while holding the other.
 
pesphoto said:
Ok ,now Im kinda confused.
Click to expand...
Possibly I was being confusing.
On the black J8, the front of the lens rotates when you focus. The actual aperture you have set should not change.
The aperture ring is quite stiff on the black J8 ... it will change the focus if you don't hold the lens when changing the aperture.

Hope this clears up any confusion I've caused.

Peter
 
Your's may just be very well lubricated. My current J8, also black, actually stays pretty sure when turning the rings, but they do turn together if I want them to. The rings of the first one I had turned very freely and did tend to move together if I didn't hold the other one in place.

If they don't turn independently, then they are seized.
 
Thanks Peter and everyone. I think i need to go home and take a much closer look at it and see what is turning when.
 
The way it works is if you turn the focus ring, the aperture numbers also rotate with the ring (but the aperture does not change as the index mark is on the focus ring.) If you want to change the aperture, you have to hold the focus ring from turning in order to do so. Because of the way this works, there are 2 aperture scales, so you can always see one of them when the focus ring is turned either towards infinity, or towards close focus. This is way harder to explain in words than to see while holding the lens!
 
That also happens with my 90 Elmars ltm. Turning the aperture ring before focusing resolves the problem. I guess some lenses were designed to work like that.
 
I have a black Jupiter 8 also. I agree with what FrankS said. The only thing different is my aperture ring is loose enough to change without holding the focus ring.
 
Hi,
Now I have a better idea of the problem, I can give you a fuller answer than in the PM I sent. All of the black J8's I have seen are of this pattern but there are some silver ones as well. There are 2 other types of silver ones as well. Although the focus units are different, the lens units are all the same except that this type has 2 aperture scales to take account of the rotating front element.

The problem is generally the grease. In the focus helix it acts like wax and gets sticky causing the focus action to get stiff and jerky. The aperture mech is two V shaped plastic cups with a ledge. The grease here gets polished and the apeture becomes much easier to turn and thus unbalances the action. The cure is a re-lube. I use a light to medium weight grease on the helix which gives a smooth fairly light focus action. I then build up a much heavier grease on the lip of the aperture cup so this becomes firmer. This puts the lens back into balance and it it not so easy to knock the aperture out whilst focussing.

Kim
 
Yes, a rotating aperture ring (with the focus ring) is inconvenient enough when it is working properly. If the aperture ring action is too loose to stay put as ou focus, or sensitive to an unitended touch, that would be a real pain!
 
Kim and Frank, thanks for the helpful info. I got home from work and took a closer look at the J8 on my Bessa R. Ok, so first I set the aperture ring to a desired setting and then I turned the focus ring. The aperture ring, sure enough, did not move. I think it's ok and Im getting the hang of how it works. Kim, the focus seems very smooth not stiff at all. Thanks for answering my PM. Im going out to shoot with it tomorrow and will process the film then let you know how it performs.
 
Sorry to resurect this thread, but I've just received my chrome J8 (SN: 6390483, does that mean it was made in 1983?)

The problem I'm having is the aperature ring is too loose, with some forward backward play as well.

Does anyone know how to tighten it up / point me in the right direction?
 
You must log in or register to reply here.
Back
Top Bottom