Jupiter 12 focusing on a Canon P

[Jiayiwong]

Hi I'm new to the forum and the world of rf cameras. I recently bought a Canon p and a Jupiter 12 lens. It fits. However the two aren't coupled correctly ie when I point at an object in infinity if I focus based on my rangefinder, the distance indicator on my lens is only 8-15 m. I would like to know if that's the case for other people with that combo and how do they focus. Do you take pictures based on estimates of distance and set the lens as such or do you still focus through the rangefinder?

Thank you

 

[xayraa33]

Hi I'm new to the forum and the world of rf cameras. I recently bought a Canon p and a Jupiter 12 lens. It fits. However the two aren't coupled correctly ie when I point at an object in infinity if I focus based on my rangefinder, the distance indicator on my lens is only 8-15 m. I would like to know if that's the case for other people with that combo and how do they focus. Do you take pictures based on estimates of distance and set the lens as such or do you still focus through the rangefinder?

Thank you

Welcome to the Forum

Test camera with an other known good lens to see if it will focus to infinity, as the RF on the camera could need adjustment.

If that is all ok then:

If you can test the lens on another camera body and see if you get the same results. It could be that the lens was dissembled and put back together incorrectly, easy to do with multi-start helical threads.

Also put camera shutter dial on B and with no film and back door open hold shutter open to see if lens cam is riding on camera RF cam properly, this might be impossible with a J-12 due to the huge protruding rear glass covering everything.

Note: with some J-12 lenses the protruding rear elements could hit or rub on the sides of the light baffles on some Canon RF cameras like the P or Canon 7

 

[Jiayiwong]

Don't have any other lenses or bodies to try. Not sure if this is the way the two pair because they were made for different systems or isit because one of my items is faulty

 

[xayraa33]

Don't have any other lenses or bodies to try. Not sure if this is the way the two pair because they were made for different systems or isit because one of my items is faulty

I have several J-12 lenses in LTM and several Canon LTM RF cameras including three Canon P bodies and two Canon 7 and several Canon VTs and except for one a very early silver finish J-12 lens all the later made black finish J-12 lenses fit these later Canon LTM RF cameras with no problem. The early made silver KMZ J-12 will only fit my Canon III camera, but this is a lens mount issue, as the lens will not fully screw in on the later Canon RF cameras.

Your problem is different, your lens fully mounts on your P but it gives you 8-15 metres at infinity so I suspect that your lens was taken apart and assembled back incorrectly if your Canon P has no problem focusing other lenses, OR the infinity setting on your Canon P's RF needs to be calibrated, easy to do and that might be worth checking out if you can't get hold of any other LTM lens to do a comparison test.

 

[Scrambler]

Firstly, there are a multitude of things that COULD be wrong, but the first thing to check is the focus. So depending on your confidence and/or willingness to get film developed either

1) Mount the camera on a tripod, focus on a clear contrasting, distant image (the moon at night, a telephone pole a mile away...), then open the back and apply translucent (cloudy) adhesive tape across the film gate. Then look at the image on the tape with a magnifier (I use a 10x loupe but other options like magnifying glass are ok). Does the image you intended to focu on come into focus? Try different distances, write down your results. try focusing by the image on the tape and write down the distance on the lens and then try using the distance on the lens and note what the viewfinder focuses on.

2) Do as many of these tests as you can with an actual film in place, taking clear notes for each frame, and take photographs at maximum aperture that you can develop and enlarge (or get scanned by the lab and enlarge).

You want to know which is wrong (and right) of the three possible issues
1) the focus of the lens
2) the image in the rangefinder/viewfinder and
3) the distance marking on the lens.

Ideally you want to be able to work out how the RF/VF distance and the lens markings match up with the actual focus. What you know now is that the RF and the lens markings do not match. But is either of them right? Maybe neither is? Maybe it's the camera, maybe the markings on the lens, maybe the whole lens setup.

 

[Jiayiwong]

Firstly, there are a multitude of things that COULD be wrong, but the first thing to check is the focus. So depending on your confidence and/or willingness to get film developed either

1) Mount the camera on a tripod, focus on a clear contrasting, distant image (the moon at night, a telephone pole a mile away...), then open the back and apply translucent (cloudy) adhesive tape across the film gate. Then look at the image on the tape with a magnifier (I use a 10x loupe but other options like magnifying glass are ok). Does the image you intended to focu on come into focus? Try different distances, write down your results. try focusing by the image on the tape and write down the distance on the lens and then try using the distance on the lens and note what the viewfinder focuses on.

2) Do as many of these tests as you can with an actual film in place, taking clear notes for each frame, and take photographs at maximum aperture that you can develop and enlarge (or get scanned by the lab and enlarge).

You want to know which is wrong (and right) of the three possible issues
1) the focus of the lens
2) the image in the rangefinder/viewfinder and
3) the distance marking on the lens.

Ideally you want to be able to work out how the RF/VF distance and the lens markings match up with the actual focus. What you know now is that the RF and the lens markings do not match. But is either of them right? Maybe neither is? Maybe it's the camera, maybe the markings on the lens, maybe the whole lens setup.

thats a good idea, will try that out! thank you guys

 

[Jiayiwong]

Just an update thank you all so much. Problem is with my camera's rf. will try to do some diy adjustments

 

[retinax]

I'm wondering if OP, lacking a known in spec body or lens, could calibrate the RF and/or lens with some measuring device like calipers? What's the axial (with regard to the lens) distance between lens flange and RF cam at infinity?
Of course one can also adjust body or lens to each other without external reference, but then both will not focus properly with another lens/body.

 

[ForestCap]

Better borrow or buy a lens that has no focusing problem before you calibrate your Canon's RF. I wouldn't trust an untested J-12 to use to calibrate a body.

 

[Scrambler]

This is sound advice in that all the previous test confirms is that the rf mechanism is out of kilter but that includes the rf cam of the lens. If someone nearby can lend you a 50mm lens (no cam) you can confirm that the camera not the lens cam is the issue.

 

[davhill]

Now I know this is contrary to the do-it-yourself attitude you've expressed, but comparing unknowns (misadjusted RF) against unknowns (potentially misadjusted lens) is a recipe for long term frustration. Get a professional CLA (clean/lube/adjust) on both camera and lens from someone familiar with Canon RFs. (You just *bought* this P, right? Its from when, 1959? It NEEDS the CLA anyways, no matter how clean it looks. Shutter speeds, if nothing else, are probably a bit wonky, and you already know the RF is off.) Yes, it'll cost you $150+, but that's part of the price of buying a camera this old.

The Canon P is a wonderful camera, and the J-12 a gem, and the combination is an inexpensive route into classic film. But /inexpensive/ doesn't mean you need to be /cheap/. Spend a bit more to get it settled right.

I am (regrettably) speaking from experience on this. Get it done right. You'll save a world of headache.

This is sound advice in that all the previous test confirms is that the rf mechanism is out of kilter but that includes the rf cam of the lens. If someone nearby can lend you a 50mm lens (no cam) you can confirm that the camera not the lens cam is the issue.

 

[IlyaB]

Assuming you have another SLR camera you may also want to check your Jupiter-12 actual focusing at infinity (collimation) using the following method: http://elekm.net/zeiss-ikon/repair/collimate/

 

[ForestCap]

Now I know this is contrary to the do-it-yourself attitude you've expressed, but comparing unknowns (misadjusted RF) against unknowns (potentially misadjusted lens) is a recipe for long term frustration. Get a professional CLA (clean/lube/adjust) on both camera and lens from someone familiar with Canon RFs. (You just *bought* this P, right? Its from when, 1959? It NEEDS the CLA anyways, no matter how clean it looks. Shutter speeds, if nothing else, are probably a bit wonky, and you already know the RF is off.) Yes, it'll cost you $150+, but that's part of the price of buying a camera this old.

The Canon P is a wonderful camera, and the J-12 a gem, and the combination is an inexpensive route into classic film. But /inexpensive/ doesn't mean you need to be /cheap/. Spend a bit more to get it settled right.

I am (regrettably) speaking from experience on this. Get it done right. You'll save a world of headache.

Both my Canon 7 and Canon L2 came with correctly functioning shutter. They hadn't been CLAed in decades but I assume they had been stored properly. The only problem I had with them was the fungus inside finder, which were easily cleaned off at home.

Unless I use a camera to make a living, I don't mind doing limited DIY works on it. If the Olympus microscope I work with goes wrong, I would call Olympus immediately and they would come fix it for free. Canon P is a very popular model, there are a lot of posts with images showing how to fix things and how to do them right.

Isn't saving the the $150+ and buy film with the money very tempting? Plus we can't ignore that many people actually enjoy the "headache" (see FSU sub-forum🙂). And I guess at the same time, they enjoy the moment when they fix the problems.