LTM (LSM) to M adapter question for proper focusing

[syuji_honda]

I have an old Elmar 50/3.5 and Bessa R3A. I only have an adapter for

90mm/28mm. Do I need the 50mm M mount adapter for accurate focusing?

Also, I will get Jupiter-9 85mm lens in screw mount. Can I use any M

mount adapter for accurate focusing? I used the Elmar with Leica CL,

but focus was off on some photos. I used the 90mm/28mm adapter with

Elmar. Wondering I should have used the 50mm adapter for accurate

focus.

[kelly_flanigan1]

The 3 different adapters in leica all are the same thickness; 1 mm; the focus will be OK with any of them. The key the keyfinder differently on a Leica M; each any of the three can be used in a pinch; the correctly one only keys up the proper frame lines. The Jupiter -9 in LTM is a gamble; only 1 in 3 of mine focuses correctly. The net is full of horror stories; my two duds are not fixable. They have missmatched helixes to lens block focal lengths. This is a grave error; not really fixable. A used Nikon or Canon 85mm might be a better bet.

[rolfe_tessem]

Any adapter will provide proper focusing.

 

The proper adapter for the focal length will automatically bring up the correct framelines in the viewfinder on an M camera. I think on the Bessa you need to select the framelines manually anyway, so it will make no difference which adapter you use.

[kelly_flanigan1]

A properly focusing Jupiter-9 on my old Bessa R is a nice light setup. It took three lenses to get one that was OK..

[rover]

On the R3a any adaptor will do for standard LTM lenses as you do select the framelines manually. If the adaptor isn't defective, focussing should not be an issue with any standard lens. The J9 may be a different issue, as not all are made to the standard LTM measurements. On some the lens to film distance is not accurate causing focusing issues. Hopefully someone will come along to add more about the J9. If not, there have been many discussions about this issue at rangefinderforum.com. The instructions of how to properly shim the lens mount to correct this problem is posted somewhere there too I think.

[kelly_flanigan1]

The J9 I have that focuses correctly; spot on with a Leica M3 with adapter; Bessa R; or Zorki 3c was made in 1959. The bastard two dud J-9 LTM are from the 1970's; and are missmatched. One can adjust the make the lens focus correct at infinity; WITH the rangefinder matched too. When focused closer; the PITCH of the HELIX is not matched to the the LENS BLOCK FOCAL LENGTH. These dud lenses are probably from a chap that regreased these LTM lenses; and failed to understand they are matched at the factory; lens block to helix. This same thing happens with Rollei TLR's; folks mix up parts; and wonder why some have focus errors. The dumbness in not the lens designers; or builders; but usually the hackers; who recycle old junk; and sometimes dont have an earthly clue of matched parts. COX model airplane engines are like thi; the pistons and cylinders are matched sets. Mix them up; soem will work great; some will bind up and stop; some will have poor compression.

[huw_finney]

The "PITCH of the HELIX is not matched to the the LENS BLOCK FOCAL LENGTH" has nothing whatsoever to do with accurate focussing. Leicas assume a lens focal length of 51.6mm, so for infinity to 1m the rangefinder cam should move 2.807mm, with a lens of 51.6mm focal length the pitch of the helix will only make the throw change. Some Leica lenses with focal lengths not very different from 51.6mm correct this by machining the cam to be slightly helical (it has a slope on it). But for focal lengths very different (90mm for example) there has to be a mechanism to make the rangefinder cam move 2.807mm when the lens focusses from infinity to 1m. This can be acheived in 3 ways, two helicies (e.g. Elmar 90), cam and follower (e.g. Elmar 135) and a very sloped cam (e.g. Minolta 90mm for CL).

[kelly_flanigan1]

RE <I>The "PITCH of the HELIX is not matched to the the LENS BLOCK FOCAL LENGTH" has nothing whatsoever to do with accurate focussing</i><BR><BR>This is why hackers create all the junk floating around on Ebay. A real sad thing.<BR><BR><BR>As a Mechanical; Optical; and Electrical engineer; I am surprised at the decline in basic understanding of how things work. <BR><BR>The Leica focusing concept is real real old; it goes back to the pre M series days; into the old LTM bodies; prior to WW2.<BR><BR> The GAIN of the lens block to movement of the focus cam is set to be unity for a "normal" about 50mm lens. This is the basis for the entire system. This was understood before WW2 even by the Russians too.<BR><BR> Even Eastman Kodak made LTM lenses; and many dozen of other lens makers too. The nominal focal lengths are abit more than 50; say 51mm. Then they would make batches of lenses; and measure each focal length; and group them in batches. Then these are matched to groupings of helixes; matched up to the focal lengths. <b>A 52mm actual focal length lens has to move a different distance to focus at 1 metre; than a 49mm lens. </b> In some cheap Ruusian old gear; the repair chap would adjust the camera to mate with the lens; at close and far settings; for the "off" lens. In Leica and more modern Ruusian bodies; folks really wanted interchangeable lenses. <BR><BR>b>The helixes are matched to the focal lengths on Leica products; to insure better focus tracking. The code numbers used for the groupings at least for Leica have been known for about 1/2 century.</b> In the 90mm Leica product; their are 4 groupings 95 for 89.5mm 00 for 90.0mm 05 for 90.5mm 10 for 91.0mm........<BR><BR>In 50mm products; about there have been about ten different codes used at least; the Elmar and Summicron have different groups. The Noctilux I have is a 00 code; grouped for a 50.0 pitch helix. The new LTM Summicron I have is a "22" code; ie matched/mated to a 52.2mm helix. A friend that has the same new #11619 lens has a lower grouping code. Mix the helixes and you will have two good looking lenses that missfocus at close distances. Collectors would not bat an eye; and just get real concerned over a non functional blem. <BR><BR><b>On a wide angle or telephoto Leica Screw mount or M lens; there is a double lens helix. The lens CAM SURFACE still has to move the same amount forward; to focus from infinity to 1 metre; for ANY lens. The double helix transfers the lens block movement to the focus cam surface. </b><BR><BR>In the many Jupiter-9's I have; the 1970's models one can unscrew the super fine pitch lens block; and set the focus any where you want. Infinity focus can be made perfect on rangefinder and film; BUT the lens helix is not matched to the lenses actual focal length. One of the lens blocks is marked inside as 86.3mm; another is 85.9mm; several more are un marked; or have hidden marks. One can swap out the lens blocks with my limited Jupiters; and get somewhat better tracking; but still it is off alot. In general the 1950's Russian Jupiters-9' I have used have focused ok or good; the 1970's reegreased to sell on Ebay crap is the mixed parts that miss focus. One can hand lap the focus cam to force one of these bastard lenses to work; this is a tall order. Sometimes the requirement is to remove material at the infinity end; an the helixes have to be juggled like rubic cube. Then a mess of material has to be removed; since there are defined keys in the lens. <BR><BR>It is interesting that folks poo poo matched parts. Leica has done this for at least 1/2 century; the Russians appear to have probably used 2 or 3 helixes on the Jupiter-9; or at least done it once as an experiment. <BR><BR>Collectors seem to crave looks over function. Mixing up and regeasing old matched lenses to create silky smooth lenses; is what Ebayers get many times with a LTM Jupiter-9. The miss focused ones appear to have been been inside several times before; like the hacker got lost; and left scribe marks everywhere. There is no adjusting of these lenses; if the lens block's focal length is miss matched to the lens block pitch. You have a bastard lens; a paperweight; a Ebay con. <BR><BR>The Russians probably had a looser tolerance than Leicas; who had 4 groupings of helixes for the 75 and 90mm products. If anything; the Russians would have to have even more groupings. Every correct focusing Jupiter-9 LTM I have used has been never messed with; and has factory dried up grease; usually from the glory days of the late 1950's. Every bastard Jupiter-9 I have bought or fooled with for friends has been a rehashed regreased lens; with mixed up parts; ie mis matched helix to lens block focal lengths.<BR><BR>In similar matter; Rollie TLR hackers mix up viewing and taking lenses; to create a good looker; for an Ebay collector; that many times has a focus tracking problem. A neighbor bought his dream F model with Planar; that focuses correctly at infinity on screen and film; but misstracks/focuses wrong at close distances. It is a nice looking paperweight for a collector to glue to thir display case.

[kelly_flanigan1]

Ideally lenses would have no tolerances; and there wiuld be no matching process. In reality; it is way lower cost to match parts; to keep costs in check. Mixing up the parts of two matched assemblies is a total crap shoot. The dice are rolled.

[huw_finney]

I am sticking with what I said, the pitch of the helix has nothing to do with accurate focussing at all. It is (as you said) how far the cam moves for a specific change in focussing distance and with one helix with a flat cam this will only work (on a Leica) with a lens of 51.6 mm focal length. This is why (as I said) some (probably most giving manufacturing tolerances) single helix Leica lenses have a non flat (i.e. and anditional correcting helix ground) cam surface. Matching the correct helix unit, one with the non flat cam is important I agree, but the helicies themselves have no affect at all.

 

BTW you picked the wrong person to accuse of not knowing how things work! I am a qualified and very experienced analogue and digital electronics engineer as well as an amateur mechanical and optical experimenter. I take my hobbies seriously, so seriously in fact I have a company sponsored optomechanical patent to my name amongst others.

 

Huw

[huw_finney]

On a positive note, your mate with the Rollei could put a correcting lens on the front of the viewing lens, chat up a local optican and bring some ground glass! Or measure it and calculate the lens required, I wouldn't worry about the effect of seperated elements but if you are put 1/2 the power either side.

[kelly_flanigan1]

HUW; a 85mm focal length and 87mm focal length lens each require a different amount of forward movement; to focus at 1 metre; when they start at the infinity position. This has been known for several centuries; and is the basic lens equation. <BR><BR>The focus cam and roller on a Leica LSM or M camera has the same movemment forward; when focused from infinity to 1 metre. (unless you want to align you camera to a freak hacked lens; with miss matched helixes)<BR><BR>A leica roller assembly or Zorki cam; can be adjusted; to focus correctly; with a bastard lens; then one has a bastard camera; that will miss focus with all other Leica lenses. <BR><BR>Most folks dont want to do this. <BR><BR>BUT folks can use an old zorki body; and adjust the pie cam to adjust the gain; so it tracks with a bad lens; and create a decent matched comb. Here at least the freak lens is not a paperweight. <BR><BR>A 85mm and 87mm lens block require a different "gear ratio" to translate the cam motion required for focusing; when adjusting the lens from infinity to 1 metre. <BR><BR>The cam motion of the rangefinder is set in stone; and is the same as before ww2. <BR><BR>If a helix set is made to fit a 85mm lens; a 85mm lens block can be made to correctly couple with a leica or zorki body. When a hacker places a 86mm lens; in a 85mm mount; one has a bastard lens; that can be made to focus at only one distance. If aligned at infinity; the missmatched set will be off at close distances. For a F2 lens of 85mm focal length; this is a grave error. One can hand lap the lenses cam surface; if on a desert island; and needs the project to pass the years away.<BR><BR>Assume the focal length of your lens is so high it is 170mm; instead of 85mm. Place a 170mm lens; in a 85mm helix set; align the lens to infinity; and only infinity will be ok. The movement required to focus a 170mm and 85mm lens from infinity to 1 meter are radically different..In the extreme example; a missmatch helix set gives a useless rangefinder. The feedback error is double. The darn poor rangefinder is amuck.<BR><BR>With a slr; there is no problem; with a rangefinder; the "focus loop" is closed around the rangefinder patch. The ONLY thing that is fed back to the body is the focus cam surface movement; which is defined. A focus of infinity to 1 metre has a defined movement; which is a standard; so folks can actually change lenses; and not mess around and have focus errors.<BR><BR> Hacking and mixing up of matched lenses creates bastard lenses that miss focus; with a correctly calibrated body. Folks who like to create "Ebay lookers" create these lenses; and fail to grasp the basic Leica focusing scheme. This creates wildly radically results when lenses are relubed by hackers; and the box of parts is mixed; and all factory matching is ruined. <BR><BR>This is why the repair life of alot of consumer items depends on how many different folks have played with the "repairs"; and done non factory adjustments that often ruin a working item. <BR><BR>Helix sets are matched to lens blocks for a reason with rangefinders. Most folks want interchangeable lenses that focus correctly with their rangefinder patches. Most folks dont want a freak rangefinder that only is aligned to one Jupiter-9; and no other lens. <BR><BR><BR>Mixing of matched lens parts; without fully understanding what is going on creats a population of lenses that have a way larger spread of performance. Some might be great; some might be ok; some might be duds. Spreading the myth that mixing up of factory matched items doesnt matter adds to the mess of junk on Ebay. The Leica repair books caution of non factory shops doing repair jobs; and creating cameras and lenses that dont focus with the general population of Leica lenses and bodies. This is why the better repair shops will require both lens and the camera to be lookied at; when folks have "focus probems". <BR><BR>Since freak lenses do exist; some repair chaps will align a lens to a body; and assume the lens is "to standard". A better shop has reference standards; so the freak lenses can be detected; and the customer consulted on waht they are trying to achieve. <BR><BR>I guess my old National Camera Repair instructors will be rolling in their graves; just learning that "Mixing of factory matched sets of helixes and lens blocks" is now bunk.."

[kelly_flanigan1]

HUW RE<I>But for focal lengths very different (90mm for example) there has to be a mechanism to make the rangefinder cam move 2.807mm when the lens focusses from infinity to 1m. This can be acheived in 3 ways, two helicies (e.g. Elmar 90),</i><BR><BR>This is what the 90mm Leica and 85mm F2 Jupiter do. <BR><BR>The helix set could be just one assembly; if magically folks could produce perfect lenses. I reality; they are grouped. The grouping makes a matched pair of 90mm lens blocks with 90mm mounts. It mates 89.5mm sorted lens blocks; with 89.5 mm moiunts. It mates 90.5mm lens blocks; with 90.5mm mounts. It mates 91.0 mm lens blocks; with 91.0mm mounts. <BR><BR>In a Leica telephoto; the Nikkor 8.5cm; 10.5cm; 13.5cm; there is a stub; which doesnt revolve. Here the lens mount pitch is different for each group of lens focal lengths sorted out for the build. Which a russian telephoto; like the Jupiter-9; there is a focus cam cylinder on the lens; which resolves. this can be played with; to force a lens to track correctly.

[kelly_flanigan1]

Huw and Syuji; it is not really clear whether the Soviets matched up helixes to lens blocks; or did a custom lap of the focus cam surface; to make the Jupiter-9 work. Some flat dont work at all; and mine are the 1970's black lenses; that have been regreased; and have mixed parts. Some have a huge error when focused say at 3 meters; and are perfect at infinity. The error is huge. The actual focal length is scribed inside several of my 1970's lenses. <BR><BR>The lenses that focus ok of mine are 1950's Jupiter-9's; chrome barrell stem grease. (a good sign; has not been hacked yet)<BR><BR>The lens barrel and helix mechanical assembly is somewhat different in the old 1950's and new 1970's design. The scheme to match parts may heve been bungled too; the formula lost. The two sputnik era Jupiter-9 is usable at all distances; the 70's era TOTALLY unuseable in most all the ones I have tested.

[winfried_buechsenschuetz1]

All I can tell from my 1962 J9 is that it focusses properly at oo and that the rangefinder image is perfect on a FED1g, LeicaIIIa and Canon7s. Focus is somewhat off at 2m and below. I rather think that the J9 had a rangefinder cam displacement matched to 52mm actual focal length. Some of the later soviet Leica imitations came with a 52mm standard lens.

 

At least on the early J9 like mine, nothing is adjustable. It looks pretty much as if the coupling pins between the three helices are factory set, i.e. drilled to measure when adjusting the lens. Of course you have to reassemble it correctly, otherwise the oo focus, the rangefinder coupling or both will be severely off. As mentioned, if (re)assembled properly, focus will be dead on at oo.

 

A not properly reassembled J9 can be assembled properly, i.e. in a way that it works correctly. But of course this will be impossible with J9's composed from parts of different items. On these ones, it is just a game of luck whether the positions of the coupling pins will fit or not.

[huw_finney]

Less words, more understanding please.

[kelly_flanigan1]

Winfried; Huw; and Syuji;<BR><BR>With a 1974 J-9; the lens block just unscrews between the focus scale and f stop ring area. One turns the filter ring area CCW to unscrew the lens block. It takes about 14 turns to remove the len block assembly. There is a shim 43mm in diameter; that varies in thickness; of about 0.3 to 2.2mm in the several J-9's I have played with. This ring sets the infinity focus on the film. One J-9 I got long ago had no shim; and the focus was wrong at all distances; even if scale focused. A chrome 1959 J-9 i have also has the same fine thread on the lens block; and can be screwed into the 1974's focus mount. The focus shim required is way different fo infinity focus; one requires almost none; another had two; and the big 2.2mm spacing. The lens mount/helix is somewhat different on the two variants. The 1974 black lens is from Litareno/PO Rubin; the 1959 is a KMZ/Krasnagorsk ; according to p 75 of Marc James Small's book on "non-leitz leica thread-mount lenses".<BR><BR>With seeral lens blocks ; one can gte them all setup for infinity focus and rangefinder focus to be correct. Then when focused closer; the error grows. No combo I have of the several junkers will make a good lens. My other 1959 lens focuses correct at infinity; and is about perfect at close focus of 1.15 metre. <BR><BR>

[syuji_honda]

Any opinion on J9 from 1980's? Anybody?