MPP rangefinder focusing - different lenses

[Jiri Vasina]

Hello, I have a question concerning rangefinder focusing with my MPP Micro Technical Mk.VII. I have a Xenar 135mm/4.7 lens, which works very well with the included RF and "rangefinder cam".

Now the question - I also have a Calumet Caltar-IIN 135mm lens - do you think it'll work with the same cam - as the stated focal lengths are the same? Or will the difference in exact focal lenses play such a role as to render it generally unusable? (The Calumet could be a little less flare-prone,...)

I know that the most definitive answer is to test it, but that would be burning a lot of sheets of film, trying all the distances,...

Thanks a lot

[Glenn Thoreson]

I believe this is one of the cameras where the lens and cam must match each other. I doubt there would be much difference but the only way to find out is shoot some film. At small apertures, you may not notice any difference. Just so you know, two otherwise identical lenses will likely be a tiny bit different in actual focal length, versus the marked focal length. Two completely different lenses of the same focal length will surely not be exactly the same.

[Paul H]

As Glenn says, the cam and lens should match (the lens serial number is usually scribed on the cam). However, on mine, the serial numbers do not match, but the focus is fine.

Give it a try - you may find it fine, or you might see that it is slightly off at one end of the focus.

The Xenar on mine is quite a respectable performer, and gives some scope for movements. I'm not sure how much difference you'll see between the two lenses.

[Pete Watkins]

There is an M.P.P. users club which costs very little to join and members are very helpful when dealing with enquiries like yours. Join through their website.
Best wishes,
Pete.

[Ash]

If you don't wish to waste a lot of film, you could try paper negatives (photo print paper, buy 4x5 or cut down larger sheets, can be loaded in the darkroom as b&w is redlight safe).

Paper negs are very cost effective for testing, however their EI is VERY low, and the resulting negative may be very constrasty (no red-light sensitivity). This shouldn't matter for tests though, after all you can tray develop and push process, focusing can be tested on a tree for example.

[Dean Jones]

Hi Jiri...another cost saver that I use for focus testing is to use a roll film back, or maybe a Polaroid back that accepts the Fuji 100 pack film, although that is quite expensive alternative at two bucks a time. An even cheaper method and what I'd try first, is to set the camera on a tripod and with the lens preview open at max aperture, get yourself a good 8x loupe and whack it (gently) on the ground glass screen.

Examine the image and check the corresponding finder split image. A good idea is to start at infinity and work in closer by a few meters at a time. Chances are that if infinity registers true, the closer distances will too, (if you're lucky).

If this looks good, then introduce some film to double check the calibration. That's the method I use when grinding a cam for the first time, or adjusting a range finder.

Cheers.

[Richard Kelham]

Do as Dean suggests and visually test the lenses first, then try film. If you find that the RF cam is not suitable then you could perhaps improve the performanc of the Xenar by fitting a lens hood.

[Jiri Vasina]

Thanks for your suggestions, I'll do as follows:

* find a lens hood to use with the Xenar
* visually test the Caltar against RF
* test with paper negative
* try it in real shooting situations with the Caltar
(* and come back to the Xenar in the end )

[scrichton]

I have just re-installed all the rangefinder stuff on mine, what you will find with 135mm lenses is that the DOF is enough that as long as infinty is ok you will be just fine.

Best to use it in a darkened room with bright lights with obviusly edged objects, then use rangefinder/GG on a tripod. I had it all setup in 1hour this way.