Rangefinder alignment

[rayfoxlee]

Hi all

There are always lots of posts about this problem, be it a Bessa or Leica, although Bessas seems to have more instances of mis-alignment than Leica, hence this posting under the CV threads.

I recently bought a Leica M2 and found a difference between vertical and horizontal alignment. The guy that did the CLA is a Leica specialist of some repute and he says that the difference is down to astigmatism. Has anyone else heard this? I just find it hard to believe that the guy who bought Voigtlander - and who is self-confessed RF addict - would get something like RF alignment wrong. Having just bought a 35mm Ultron, the fit and finish of the lens is outstanding, so I reckon the Bessa's are made to same high standard.

Any thoughts on this one, guys. Ooops, 'girls' as well! One does have to be PC on such issues, although I have never seen a girl/woman/lady toting a RF! Are there any out there?? 🙄

 

[jlw]

"Astigmatism" is a general term for any optical aberration in which rays on different axes (e.g. vertical and horizontal) focus on different planes. So when your technician said that, he may simply have meant that that's what you call it when the vertical and horizontal alignments differ.

In any case, vertical and horizontal alignments can be adjusted independently on both Leicas and Bessas, so I don't see why it should be an issue.

I think one reason Bessas get more complaints about RF misalignment than Leicas is that the Bessa's rangefinder optical system is more sensitive to alignment of the eye behind the eyepiece (possibly because the Bessa's RF optics were designed to be very compact.) You may have noticed that if you adjust your Bessa's RF alignment absolutely perfectly, then shift your eye slightly up and down or from side to side, the alignment suddenly will be slightly "off."

I can even see how, if your EYE is afflicted with astigmatism and you wear glasses or contacts to correct it, the additional "spherocylindric" curve of your corrective lenses might interact with the camera's RF optics in such a way as to make the alignment appear slightly off. So that's another possibility for what your technician meant...

 

[Fred]

I have to agree with jlw.

I have to use corrective vision either with glasses or contact lenses for both long sight and anastigmatism.

With glasses the M7 RF is pin sharp in alignment , with my new 'toric' (anastigmatism corrected) contact lenses the view is the same. However when I used my old 'normal' lenses that corrected for long sight only the RF looked like it was out of alignment on the vertical.

If that is all thats wrong then corrective vision should sort it. If it's the camera internals, well thats another story.

 

[former member]

Astigmatism generally refers to the property of a lens, not an RF.

I am used to performing vertical alignment first, then horizontal alignment. I have done this on the Retina IIIS, Canon 7, and Nikon RF's. The vertical alignment often affects horizontal alignment, and you "kind of get the two to converge". But, a properly aligned RF means horizontal and vertical alignment, not just one or the other.

 

[pvdhaar]

I think one reason Bessas get more complaints about RF misalignment than Leicas is that the Bessa's rangefinder optical system is more sensitive to alignment of the eye behind the eyepiece (possibly because the Bessa's RF optics were designed to be very compact.) You may have noticed that if you adjust your Bessa's RF alignment absolutely perfectly, then shift your eye slightly up and down or from side to side, the alignment suddenly will be slightly "off."

That's not exclusive to the Bessa-R, this also happens on the Konicar Hexar RF which has the same baselength as an M6. Move your eye out of center and you see a double image appear in the rangefinder spot.

But when judging alignment you also need to make sure that the subject you're focussing on is in a plane that's exactly parallel to the film plane. If not, you'll see a single line on a subject as crossing lines in the rangefinder spot. This also gives the impression of mis-alignment.