Carburo
Rangefinding Architect
Is the FED's screw lens mount the same of Voigtlanders (Cosina)?
If the answer is yes, and the lenses are interchangeable, I'm thinking about a hybrid...
If the answer is yes, and the lenses are interchangeable, I'm thinking about a hybrid...
Pherdinand
the snow must go on
Well, aren't both of them LTM? (You mean the Bessa R i guess, the screwmount, not the bayonet nor your 1938 folding)
)
The lenses will fit, but do not be surprised if the focus is off when used close-up and wide-open. I have read on several sites that the Russian SCrew Mount was tied to the 52.3mm lens standard while the Leica is tied to 51.6mm. The Jupiter-8 and Helios-103 are 52.3mm lenses. It made sense to calibrate the RF in the Russian cameras to that focal length rather than have two formulations of the same lens, one at 51.6mm and the other at 52.3mm.
The difference is about 1" at a 36" range. The same "error" occurs when using Nikkor S-Mount lenses on a Contax Body. At F2 the DOF is enough to cover the error.
Thoughts anyone?
The difference is about 1" at a 36" range. The same "error" occurs when using Nikkor S-Mount lenses on a Contax Body. At F2 the DOF is enough to cover the error.
Thoughts anyone?
P
pshinkaw
Guest
My opinion is that there is enough imprecision in Soviet LTM construction to make that hypothesis very diifcult to prove. My experience with Fed and Zorki bodies is that +/- 1" at 36" object distance is better than what most of these old bodies can hold.
I don't have a Voigtlander, but I have subbed Leitz lenses onto Fed'sand Zorki's and compared them to Soviet lenses of similar focal length. While I haven't had any problems related to focusing accuracy, I also haven't tested them at ranges closer than about 4-5 feet and at apertures larger than about f4.
Perhaps someone with an R or R2 and a Soviet camera can make some tests?
There is also a collateral issue related to whether an LTM lens can physically mount on all LTM bodies. Most of the higher quality LTM bodies use a roller within the body to couple the lens to the rangefinder. A roller equipped body can couple to any of the LTM lenses. However, the Soviet cameras use a wedge or pie shaped eccentric cam. This will hang up on some lenses. Some of the Steinheil Culminar's have diificulty in coupling as well as some of the longer Canon lenses. The problem is with lenses that have a "tongue" coupler rather than the annular ring. These lenses are designed to couple to cameras with the roller.
An additional problem with Soviet cameras is also related to lack of quality control. Some of the rangefinder couplig arms on Soviet cameras hang lower than others. If they hang low enough, they will jam the fcousing coupler on the lens.
These are some of the reasons why I and some others prefer to buy one body for each lens and treat them as a permanent match rather than interchanging lenses and bodies freely. After all, you can buy a good useable Fed-2 for a few dollars more than a high quality machined aluminum rear lens cap!
-Paul
I don't have a Voigtlander, but I have subbed Leitz lenses onto Fed'sand Zorki's and compared them to Soviet lenses of similar focal length. While I haven't had any problems related to focusing accuracy, I also haven't tested them at ranges closer than about 4-5 feet and at apertures larger than about f4.
Perhaps someone with an R or R2 and a Soviet camera can make some tests?
There is also a collateral issue related to whether an LTM lens can physically mount on all LTM bodies. Most of the higher quality LTM bodies use a roller within the body to couple the lens to the rangefinder. A roller equipped body can couple to any of the LTM lenses. However, the Soviet cameras use a wedge or pie shaped eccentric cam. This will hang up on some lenses. Some of the Steinheil Culminar's have diificulty in coupling as well as some of the longer Canon lenses. The problem is with lenses that have a "tongue" coupler rather than the annular ring. These lenses are designed to couple to cameras with the roller.
An additional problem with Soviet cameras is also related to lack of quality control. Some of the rangefinder couplig arms on Soviet cameras hang lower than others. If they hang low enough, they will jam the fcousing coupler on the lens.
These are some of the reasons why I and some others prefer to buy one body for each lens and treat them as a permanent match rather than interchanging lenses and bodies freely. After all, you can buy a good useable Fed-2 for a few dollars more than a high quality machined aluminum rear lens cap!
-Paul
John Robertson
Well-known
I have a FED 2 and a FED 3L, and have used my CV lenses on both, they all focus OK but the 15mm Heliar does not "line -up" properly on the FED2 resulting in the fixed petal shaped hood being out of alignment. Its OK on the 3L. I have tried them on my friends Canon7s, and they were too tight to screw in comfortably without force!!! Strange!
fed_dude
Newbie
Are Russian "normal" lenses for RF cammed to correspond to an arbitrary focal , or does the RF movement exactly follow their focus extension?
P
pshinkaw
Guest
I don't think there is enough evidence to prove or disprove either proposition. Some lenses seem carefully calculated, others seem totally arbitrary. Since they are all very old and mostly well used, wear becomes a contributory factor as well.
Keep in mind that Soviet camera bodies have 2 rangefinder adjustments rather than just one. One adjustment is for the maximum focus distance at infinity and the other is for the minimum focusing distance. The objective is to get both settings correct.Supposedly all the settings in between will follow.
-Paul
Keep in mind that Soviet camera bodies have 2 rangefinder adjustments rather than just one. One adjustment is for the maximum focus distance at infinity and the other is for the minimum focusing distance. The objective is to get both settings correct.Supposedly all the settings in between will follow.
-Paul
L
laurentvenet
Guest
good conclusion Paul, I did not know that fact, I'm gonna look at this with my bessa R, fed 3 and my CV lens + jupiter 8
doubs43
Well-known
Paul, could you be more specific about the RF adjustments on FSU cameras? Most LTM models have the horizontal adjustment via a screw accessed through a hole beside of the window. If I read Maisenberg correctly, vertical adjustment requires un-glueing and re-glueing one of the prisms. I'm not familiar with the "near" and "distant" dual adjustments. Can you enlighten me, please?
I have a Zorki-4 that focuses to infinity perfectly with 35mm & 90mm Elmar lenses. That's by the RF and ground glass at the film plane. The 135mm Hektor, however, will not fit for exactly the reasons you have detailed. My FED-2 will not accept the 35mm or 135mm for the reason that the body RF coupling is much too sharp.
I'm also finding that there's considerable difference in Kiev (Contax copy) bodies and the rangefinders, especially close focusing. Lens that focus to infinity with the RF aren't always at infinity on ground glass and are off quite a bit at closer distances.
Walker Smith
I have a Zorki-4 that focuses to infinity perfectly with 35mm & 90mm Elmar lenses. That's by the RF and ground glass at the film plane. The 135mm Hektor, however, will not fit for exactly the reasons you have detailed. My FED-2 will not accept the 35mm or 135mm for the reason that the body RF coupling is much too sharp.
I'm also finding that there's considerable difference in Kiev (Contax copy) bodies and the rangefinders, especially close focusing. Lens that focus to infinity with the RF aren't always at infinity on ground glass and are off quite a bit at closer distances.
Walker Smith
P
pshinkaw
Guest
The traditional screw adjust is behind a cover screw on the front of most Soviet LTM cameras. It is essentially a stop screw that sets the infinity limit. It is used only to set infinity.
The rangefinder coupler cam is inside the throat of the lens mount. On Leica's and Canons it is a roller. On Soviet cameras it is an eccentric cam. Maizenberg describes how to make a wrench to adjust this cam. Basically you turn the cam so that a different radius is present to the lens coupling ring. When you find that "sweet spot" you have the near limit adjusted.
However, the cam sometimes gives you more than one "sweet spot" Sometimes you can get a perfect near adjustment at 12 feet and it will be off at 3 feet. It takes a little trial and error to get it right.
The purists set their rangefinders for infinity and 1 meter. I've never been able to get the 1 meter setting right and still have the lens scale read correctly at 5 meters (distance across the dining room and kitchen). So, I use infinity and 5 meters. It covers almost everything I would shoot with a rangefinder anyway. It actually works all the way in to 1 meter satisfactorily.
The rangefinder should be calibrated AFTER the flange-film distance has been verified to be 27.78 - 28.82 mm. Otherwise you will have a perfectly calibrated ranbefinder setting an out-of-focus lens.
-Paul
-Paul
The rangefinder coupler cam is inside the throat of the lens mount. On Leica's and Canons it is a roller. On Soviet cameras it is an eccentric cam. Maizenberg describes how to make a wrench to adjust this cam. Basically you turn the cam so that a different radius is present to the lens coupling ring. When you find that "sweet spot" you have the near limit adjusted.
However, the cam sometimes gives you more than one "sweet spot" Sometimes you can get a perfect near adjustment at 12 feet and it will be off at 3 feet. It takes a little trial and error to get it right.
The purists set their rangefinders for infinity and 1 meter. I've never been able to get the 1 meter setting right and still have the lens scale read correctly at 5 meters (distance across the dining room and kitchen). So, I use infinity and 5 meters. It covers almost everything I would shoot with a rangefinder anyway. It actually works all the way in to 1 meter satisfactorily.
The rangefinder should be calibrated AFTER the flange-film distance has been verified to be 27.78 - 28.82 mm. Otherwise you will have a perfectly calibrated ranbefinder setting an out-of-focus lens.
-Paul
-Paul
doubs43
Well-known
Paul, that's an excellent description and I understand perfectly. Thank you.
Walker
Walker
S
Scarpia
Guest
Two exeptions: On a Fed 5 the rear flange of the Nokton 50mm 1.5 runs into the raised viewfinder assembly before it is fully screwed in and probably doesn't focus perfectly. I would suspect the same thing is true with a Fed 4. The second exeption I am aware of is with the CV 90mm 3.5 which has a rangefinder "notch" rather than a cam. Works fine on CV cameras, but locks up on a FSU camera and can conceivably be damaged.
Kurt M.
Kurt M.