Setting up RF Cam / Infinity on Master technika

[charles_mackay]

I acquired a Schneider Tele-Arton 5.6/270mm lens (SN 10831578,

engraved "Technika") on a flat Linhof board, with matching numbered

cam (it is the appropriate Tech V / Master style cam). After setting

the lens at infinity at any of the three bed positions

(wide/normal/long focus) I find that the RF does not correctly focus

at distances closer than infinity. (The instructions for the camera

provide no information as to which of the three bed positions would be

appropriate to this particular lens, so I have tried them all.)

 

What am I doing wrong? It seems as if it should work, with the 150mm

lens that came with the camera (Sironar-N 5.6/150 on recessed board)

the RF works fine. (Infinity is being set correctly; I am doing it

using another camera to focus on the groundglass using a technique

described elsewhere in this forum and have verified my technique

against the infinity setting of the 150mm lens that works.)

[john_stafford2]

Forget about the current infinity stops. You can't be sure for what lens they are set. Choose the set farthest from the film plane, then loosen the tiny screws that hold it to the rail (just loosen, don't remove). Put the 270mm lens to an infinity subject (way, way far away) and focus using the ground-glass. Then slide the stop up against the rail and tighten the screws. There. Done. You never have to set the stops again.

[brian_ellis16]

I don't understand what you're doing. It sounds like you may be assuming that one of three existing infinity stops set by someone else using lenses unknown to you will be correct for your lens. Unless you know that one of those postiions was set using a 270mm telephoto lens that's not correct (and even if one of them was set using that type lens, it still might not be correct for your lens). The reason the instruction book doesn't provide information as to which of the three bed positions would be appropriate to this particular lens is that the infinity position varies depending on which lens is being used so there's no way the instruction book can specify a position for your lens. Also, you're using a telephoto lens so your infinity position isn't going to be the same as an infinity position set with a normal lens (and for the same reason comparisons with the infinity position for your 150mm lens won't be particularly relevant to anything since it's a normal lens, not a telephoto).

 

I also don't understand why you're concerned with the infinity position when you're focusing on something closer. Just pick the spot on which you want to focus and move the lens until the split images in the rangefinder come together. There's no need to start at infinity though starting somewhere around there will speed things up. Also, why are you setting infinity by using another camera to focus on the ground glass? I'm not familiar with this technique, maybe there's something that I don't know about that causes you to do it but the more common way would be to put the 270mm lens on your camera and focus on something a mile or so away (it's pretty easy to find a billboard on a highway to use as your focus point).

 

Possibly I'm misunderstanding just what it is you're doing and if so I apologize but some of the things in your question aren't entirely clear to me.

[mark_rossano]

Also, make sure that the cam is not for a Tech IV. If it's for a V/Master, it will have the lens serial number and focal length engraved. If it's for a IV, it will also have a second serial number (the body number) on the reverse side of the cam, but will otherwise be identical in appearance to a cam for the later bodies. If you have a Tech IV cam, it probably won't focus accurately on a V or Master (or, for that matter, on any Tech IV body other than the one the cam was made for).