Voigtlander Color Skopar 35/2.5 LTM focus range

[mtnbkr]

I recently acquired this lens to go with my Canon VT and think there might be a problem. I took it for a walk today and noticed when I focused closer than 2.75' the rangefinder patch stopped moving even though the lens still had more focusing movement down to its minimum of 2.2' or so. Doing some testing at home with a measuring tape, it seems to be pretty spot on until the rangefinder patch stopped moving. I can feel the lens lose contact with the camera's RF cam at the point the patch stops moving. With the lens out of the camera, it's clear the lens is still moving, so it's not jammed or anything. It's as if the cam on the lens is too short or something.

At infinity, while focusing on a distant object about 100' away, it seems to focus just a hair past infinity (ie I have to back off the tiniest bit to line up the patch).

The lens doesn't appear to be modified, it's perfect with no marks or mangled screws or anything that would point to damage or modification. The camera is perfectly matched with my Canon 50/1.8 lens (proven on film and via manual measurement).

It's as if the lens has more movement than the camera's rangefinder. Is this normal for old cameras and newer lenses or is there another issue at play? Losing the closest focus range isn't a huge issue as I wouldn't be taking pictures that close with this camera (paralax becomes an issue and I'm not into extreme close ups), but I'd like to understand what is going on.

Chris

 

[BradS]

I do not know what the specific situation is with your camera lens but in general, yes, it is quite common that a newer RF coupled lens is able to focus closer than an older RF camera. See for example the current gnashing of teeth over the newest Leica and CV lenses that focus to 0.5 meters when the closest any Leica M film camera will focus is 0.7meters. It goes the other way too...old 50mm Summicrons, for example, only focus to 1m but the Leica M film cameras can close focus to 0.7m

 

[brbo]

I don't think any Canon LTM lenses focused down to 0.7m as your Skopar 25/2.5 LTM can. So, your VT rangefinder might be coupled even past 1m, but not quite down to 0.7m.

I'd say there is nothing wrong with the camera or the lens. Just the way it is. Leica M3, for example, would lose coupling much sooner (just below 1m).

 

[mtnbkr]

Thanks BradS and brbo! Now that you mention it, I do recall reading about these limitations in other cameras. I'm fine with that.

Chris

 

[reddesert]

The way that an interchangeable lens rangefinder works, the camera RF is calibrated for the lens extension required by some fiducial focal length (about 50-52mm, slightly different between systems). The lens cam essentially pretends to the camera that the lens is a lens of this fiducial focal length ~50-52mm. That is, the lens extends by some number of mm to focus, and the cam moves by a different number of mm.

50mm RF lenses typically have a closest focusing of about say 0.7-1 meters. So that's all the motion that the camera body can follow. The 35mm lens can physically focus closer, because wide angle lenses don't require a large physical extension, but the cam moves too much for the camera to follow.

 

[mtnbkr]

The way that an interchangeable lens rangefinder works, the camera RF is calibrated for the lens extension required by some fiducial focal length (about 50-52mm, slightly different between systems). The lens cam essentially pretends to the camera that the lens is a lens of this fiducial focal length ~50-52mm. That is, the lens extends by some number of mm to focus, and the cam moves by a different number of mm.

50mm RF lenses typically have a closest focusing of about say 0.7-1 meters. So that's all the motion that the camera body can follow. The 35mm lens can physically focus closer, because wide angle lenses don't require a large physical extension, but the cam moves too much for the camera to follow.

Thanks! I'm fairly new to interchangeable lens rangefinders (this is my first) and didn't know that. It's not a problem now that I know and can work with/around it.

Chris