jlw
Rangefinder camera pedant
It seems to happen every time I read a thread about R-D 1 rangefinder problems: I get to looking at mine (which has been making fine pictures with no problems) and start thinking,"Maybe I could tweak it to make it just a little better..."
Usually the result is that I get out my toothpicks and Phillips screwdriver and whip off the accessory shoe, then waste some time diddling with it before I realize it was fine the way it was and I might as well have left it alone.
Yesterday, though, things got worse -- I fiddled with all three screws and wound up making a real mess, which I realized couldn't be straightened out without taking off the top cover. Yikes!
Fortunately, the instructions on Rich C.'s excellent R-D 1 website carried me through, and I was able to remove the cover and get the rangefinder adjustments back to where they belong (and where they had been in the first place, if only I had had sense to leave well enough alone!)
While I was "under the hood," I did take a few pictures to supplement the ones on Rich's site. Those wondering what the R-D 1's RF module looks like might enjoy the web page I've put up; click this link to see it.
Incidentally, don't ever let anyone tell you the R-D 1 isn't a well-made camera! Everything I saw in there was tidy, nicely finished, and cleanly designed. The RF module itself is tiny, yet contains many parts that must have required hand assembly; building it must have required the craftsmanship of some very patient and dextrous people!
Here's a teaser pic from the page:
Usually the result is that I get out my toothpicks and Phillips screwdriver and whip off the accessory shoe, then waste some time diddling with it before I realize it was fine the way it was and I might as well have left it alone.
Yesterday, though, things got worse -- I fiddled with all three screws and wound up making a real mess, which I realized couldn't be straightened out without taking off the top cover. Yikes!
Fortunately, the instructions on Rich C.'s excellent R-D 1 website carried me through, and I was able to remove the cover and get the rangefinder adjustments back to where they belong (and where they had been in the first place, if only I had had sense to leave well enough alone!)
While I was "under the hood," I did take a few pictures to supplement the ones on Rich's site. Those wondering what the R-D 1's RF module looks like might enjoy the web page I've put up; click this link to see it.
Incidentally, don't ever let anyone tell you the R-D 1 isn't a well-made camera! Everything I saw in there was tidy, nicely finished, and cleanly designed. The RF module itself is tiny, yet contains many parts that must have required hand assembly; building it must have required the craftsmanship of some very patient and dextrous people!
Here's a teaser pic from the page:
Terao
Kiloran
Interesting! And scary...
jvr
Well-known
Wow! Nice job, jlw, and thanx for posting!
All the info on RD1 innards is VERY welcome: one day, we'll probably have to live on our own regarding after-sales servicing...
All the info on RD1 innards is VERY welcome: one day, we'll probably have to live on our own regarding after-sales servicing...
mwooten
light user
jlw,
I second the sentiment of the others--thanks and great job (especially if you got it put back together, a problem I sometimes have).
After seeing the slotted plate for the frame lines, and after reading Rich C.'s article about drilling holes for a 90mm lens, I had the thought of replacing the frame-line slotted plate with another, made from photo-etched brass that has 90mm lines. One could use the 28mm setting, although I guess the mask would need to be altered also.
Anyway, maybe it's something for you hotrodders to think about.
Michael
I second the sentiment of the others--thanks and great job (especially if you got it put back together, a problem I sometimes have).
After seeing the slotted plate for the frame lines, and after reading Rich C.'s article about drilling holes for a 90mm lens, I had the thought of replacing the frame-line slotted plate with another, made from photo-etched brass that has 90mm lines. One could use the 28mm setting, although I guess the mask would need to be altered also.
Anyway, maybe it's something for you hotrodders to think about.
Michael
iml
Well-known
Excellent stuff. I'm really hoping I never have to take mine to bits!
Ian
Ian
jlw
Rangefinder camera pedant
I wasn't crazy about having to open up mine either. But then again, my motto when it comes to cars is, "You don't really own it until you've had the engine out," so I figured I'd have to apply the same thinking to cameras and come to grips with it.
Actually, removing the top cover is less scary than on some other cameras I've attempted -- there aren't any springs bearing against the top plate to come popping out, or tiny detent balls to fall out and get lost. Unplugging the two ribbon cables is a fairly delicate operation (I wish I'd taken a picture of that; sorry!) because one of them is underneath another cable, but the connectors themselves (although tiny) are fairly robust, so it's just a matter of dexterity. Cosina did what seems like quite a good job of minimizing the parts count -- my favorite was the little slotted disc that retains the wind lever securely, yet comes off with a simple press sideways. I've seen other cameras that use quite a stack of tiny, hard-to-reassemble parts to duplicate the function of this one simple piece.
The only "gotcha" I encountered during reassembly was with the ISO dial: This has a long "finger" that reaches down through a rotating slot in the top cover. When reinstalling the dial I managed to move the slot out of position, so the finger wouldn't go through it; once I realized what was going on, it was no problem to tease the slot gently back into the correct position with a toothpick.
Although I still wouldn't recommend delving into your R-D 1 purely for recreation (and while I still suspect many of my own attacks of "needtoadjusttherangefinderitis" are really caused by eye fatigue, not lining up my eye behind the eyepiece, etc., rather than the RF actually being out of adjustment) I do have to say that it wasn't as big a trial as I had feared. And once the cover is off, it's a lot easier to adjust the screws than it is working through the opening under the accessory shoe.
Incidentally, my camera is out of warranty. If yours isn't, my advice would be don't mess with it -- make Epson fix it!
Actually, removing the top cover is less scary than on some other cameras I've attempted -- there aren't any springs bearing against the top plate to come popping out, or tiny detent balls to fall out and get lost. Unplugging the two ribbon cables is a fairly delicate operation (I wish I'd taken a picture of that; sorry!) because one of them is underneath another cable, but the connectors themselves (although tiny) are fairly robust, so it's just a matter of dexterity. Cosina did what seems like quite a good job of minimizing the parts count -- my favorite was the little slotted disc that retains the wind lever securely, yet comes off with a simple press sideways. I've seen other cameras that use quite a stack of tiny, hard-to-reassemble parts to duplicate the function of this one simple piece.
The only "gotcha" I encountered during reassembly was with the ISO dial: This has a long "finger" that reaches down through a rotating slot in the top cover. When reinstalling the dial I managed to move the slot out of position, so the finger wouldn't go through it; once I realized what was going on, it was no problem to tease the slot gently back into the correct position with a toothpick.
Although I still wouldn't recommend delving into your R-D 1 purely for recreation (and while I still suspect many of my own attacks of "needtoadjusttherangefinderitis" are really caused by eye fatigue, not lining up my eye behind the eyepiece, etc., rather than the RF actually being out of adjustment) I do have to say that it wasn't as big a trial as I had feared. And once the cover is off, it's a lot easier to adjust the screws than it is working through the opening under the accessory shoe.
Incidentally, my camera is out of warranty. If yours isn't, my advice would be don't mess with it -- make Epson fix it!
jim_buchanan
Established
Rangefinder Backlash?
Rangefinder Backlash?
jlw, after this last operation, any thoughts on rangefinder backlash improvement? Upon initial inspection, I was satisfied with my R-D1 focus accuracy. However, I have noted a slight front focusing with longer focal lengths, depending if I approach the focus point from infinity or from minimum focusing. I get better accuracy if I approach focus from minimum distance.
In my mind, it is imperative to have good focus accuracy in a rangefinder, or at least the best one can achieve.
Any ideas on the R-D1?
Rangefinder Backlash?
jlw, after this last operation, any thoughts on rangefinder backlash improvement? Upon initial inspection, I was satisfied with my R-D1 focus accuracy. However, I have noted a slight front focusing with longer focal lengths, depending if I approach the focus point from infinity or from minimum focusing. I get better accuracy if I approach focus from minimum distance.
In my mind, it is imperative to have good focus accuracy in a rangefinder, or at least the best one can achieve.
Any ideas on the R-D1?
jlw
Rangefinder camera pedant
NOTE: Please disregard this post. After reading RichC's responses below, I'm convinced by his point of view and no longer think that failure to reseal the adjusting screws could be a cause of backlash. (I still think it's a good idea to reseal the screws, but only to keep them from vibrating out of position.) Originally I was going to delete this post, but decided to leave it in case anyone still had use for the illustrations and descriptions.
====================
QUOTE=jim_buchanan]jlw, after this last operation, any thoughts on rangefinder backlash improvement?[/QUOTE]
I do have some thoughts, but please understand that they are very speculative! I'm going to list some guesses at things that might cause RF backlash, based on my casual look at the mechanism, but I don't know that they cause backlash. So, see what you think, but don't necessarily take any action based on my speculations!
For those coming late to this discussion, "lash" in general is the clearance between moving parts in a mechanism. For example, I have an old 1970s sports car, and one of the things I have to do every spring is set the "valve lash" -- the amount of gap between the top of the valve and the rocker arm that opens it. Too much lash makes the mechanism sloppy, and not enough binds it up so it can't operate freely.
"Backlash," specifically, is the lash that occurs when a mechanism reverses its direction, and this is what people worry about on the R-D 1 (and other RF cameras, for that matter.) The way it manifests itself is this: You're trying to focus on something, so you turn the focusing ring in one direction (say, from infinity toward close) watching the RF-patch image move smoothly as you do so. Then, you overshoot the focus point a bit, so you turn the focusing ring the opposite way. Instead of immediately reversing direction, the RF patch image stops moving briefly; then, after you've turned the ring enough to "take up the lash," it starts moving in the opposite direction as it should. You can see that if there's enough backlash, you'll find yourself in a situation in which the rangefinder focuses accurately when you turn the focusing ring in ONE direction (say, from infinity to close) but not when you turn it in the other direction (from close to infinity.)
A certain amount of backlash isn't uncommon in RF cameras, and it's probably almost impossible to eliminate it completely. How it got into our collection of R-D 1 neuroses, if I recall correctly, is that when people started sending R-D 1s to technician Don Goldberg for rangefinder adjustments, he noted that a certain fraction of them seemed to have enough backlash to affect accuracy.
So, now you know what backlash is and why I was asked if I saw any obvious causes and cures when looking at the R-D 1's RF mechanism. Again, remember that all this is speculative, but I'm going to group my suspicions into three categories:
1 - CAUSES OF BACKLASH THAT HAVE NOTHING TO DO WITH THE RF
This mostly would involve lenses; some lenses have a certain amount of lash in the focus-cam mechanism, so if you've got a backlash problem, you can't rule this out as a possible cause. Obviously, if that's where the problem lies, you can adjust your R-D 1 until you're blue in the face without resolving it.
2 - CAUSES THAT INVOLVE THE RF, BUT YOU CAN'T DO ANYTHING ABOUT THEM
I can think of one area that seems as if it could be a possible cause of backlash; again, remember that I didn't actually observe any in this specific area. But when trying to turn the close-range adjustment screw (seen in the following picture from Rich C's website) I noticed that the lever on which the screw rides flexed noticeably when I pressed down on the screw. (It helped to support the lever from underneath with the barrel of a screwdriver.)
The lever connected to this screw is one of several long levers that connect the coupling arm in the lens throat to the RF module. They're underneath the module and mostly invisible. Again, note that I did not observe any flex in these levers along the direction they move as you focus, so there is no reason to assume they ARE an inherent cause of backlash. But I could easily imagine that if one of these levers did flex or twist during focusing, it would cause backlash. And if it did, there basically wouldn't be anything you could do about it.
3 - BACKLASH YOU MIGHT BE ABLE TO TREAT
This one is not only speculative, but potentially controversial, because I'm about to contradict something on Rich C's website, and he knows a lot more about this stuff than I do. But to understand my speculations, first look at the following picture of the adjusting mechanism for the RF module:
In this picture you see the now-famous screws for adjusting the RF image focus, infinity position, and vertical alignment. They work by changing the position of the swinging lens that moves the RF image. To make this a bit clearer, I drew a not-very-accurate schematic of the swinging lens and its adjustments:
What I want you to notice is how the RF-focus and infinity screws (the two left ones) work. They are NOT micrometer-type adjustments that work by moving something along their threads. Instead, they are eccentrics -- the screw head turns an off-center portion of the shaft, which rides in a slot in the adjustment plate. As the off-center portion turns, it presses against the slot and causes the plate to move from side to side.
When turning these screws in my R-D 1, I noticed that there was a small amount of free movement before the plate started moving. Obviously, this meant that there was a bit of clearance between the slot and the eccentric section; there'd almost have to be, or the mechanism would have a lot of friction and would wear more quickly.
So, I could at least imagine the possibility that when you reversed focusing direction, there'd be some wasted motion in the adjustment plate until it "took up the slack" in the slots -- unless the screws were sealed to the plate.
In other words -- and here comes the controversial part -- I suspect that the sealer used on the RF adjusting screws is necessary to reduce backlash.
Now, Rich says on his site that the screws have enough friction that they don't require sealer, and for all I know he may be right. As I said, this is speculation.
But my speculation is that if you've removed the sealer from your R-D 1's adjusting screws with solvent, or if you've loosened its grip through too many attempts at adjustment, this MIGHT (again, only "might") be a potential cause of backlash. Without any sealer, reversing the focusing direction would cause the adjustment plate to shift around to the extent of the clearance in the screw slots, until they pressed up against the eccentric screws from the opposite direction.
I just want to emphasize one more time that I am only GUESSING, that Rich apparently thinks differently, and he knows a lot more about camera innards than I do! In other words, I wouldn't recommend delving into your R-D 1 just to re-seal the sealer.
And I also want to emphasize that the RF almost undoubtedly was designed to reduce the risk of this. I didn't take the R-D 1 apart far enough to see, but on other cameras I've examined, the design precludes the possibility of the adjustments producing focusing lash. Typically the whole moving portion -- the adjustment plate, the eccentric screws, and the moving lens frame -- sits on a movable base, and it's this base that turns the moving lens in response to the action of the focus coupler in the camera throat. The adjustment screws move the adjustment plate only relative to the movable base plate -- there's no drag on them during focusing, so there's no reason they should be subject to backlash.
Again, that's the way it should be, and I'm pretty sure based on what little I could see of the R-D 1's insides that its rangefinder is designed to be this way. But I could also imagine that extra drag on the moving lens (not sure where it would come from, but it's a possibility) might get transferred to the adjustment plate and cause it to wiggle enough to produce backlash.
At any rate, after I did mine, I did re-seal the screws (using automotive "thread locker") and if you think my speculations are plausible, you might want to do the same if you have to do a top-off RF adjustment for some other reason. After all, Cosina did put sealer on the screws in the first place, so it's not as if you're doing anything "foreign" to the camera by re-sealing them.
====================
QUOTE=jim_buchanan]jlw, after this last operation, any thoughts on rangefinder backlash improvement?[/QUOTE]
I do have some thoughts, but please understand that they are very speculative! I'm going to list some guesses at things that might cause RF backlash, based on my casual look at the mechanism, but I don't know that they cause backlash. So, see what you think, but don't necessarily take any action based on my speculations!
For those coming late to this discussion, "lash" in general is the clearance between moving parts in a mechanism. For example, I have an old 1970s sports car, and one of the things I have to do every spring is set the "valve lash" -- the amount of gap between the top of the valve and the rocker arm that opens it. Too much lash makes the mechanism sloppy, and not enough binds it up so it can't operate freely.
"Backlash," specifically, is the lash that occurs when a mechanism reverses its direction, and this is what people worry about on the R-D 1 (and other RF cameras, for that matter.) The way it manifests itself is this: You're trying to focus on something, so you turn the focusing ring in one direction (say, from infinity toward close) watching the RF-patch image move smoothly as you do so. Then, you overshoot the focus point a bit, so you turn the focusing ring the opposite way. Instead of immediately reversing direction, the RF patch image stops moving briefly; then, after you've turned the ring enough to "take up the lash," it starts moving in the opposite direction as it should. You can see that if there's enough backlash, you'll find yourself in a situation in which the rangefinder focuses accurately when you turn the focusing ring in ONE direction (say, from infinity to close) but not when you turn it in the other direction (from close to infinity.)
A certain amount of backlash isn't uncommon in RF cameras, and it's probably almost impossible to eliminate it completely. How it got into our collection of R-D 1 neuroses, if I recall correctly, is that when people started sending R-D 1s to technician Don Goldberg for rangefinder adjustments, he noted that a certain fraction of them seemed to have enough backlash to affect accuracy.
So, now you know what backlash is and why I was asked if I saw any obvious causes and cures when looking at the R-D 1's RF mechanism. Again, remember that all this is speculative, but I'm going to group my suspicions into three categories:
1 - CAUSES OF BACKLASH THAT HAVE NOTHING TO DO WITH THE RF
This mostly would involve lenses; some lenses have a certain amount of lash in the focus-cam mechanism, so if you've got a backlash problem, you can't rule this out as a possible cause. Obviously, if that's where the problem lies, you can adjust your R-D 1 until you're blue in the face without resolving it.
2 - CAUSES THAT INVOLVE THE RF, BUT YOU CAN'T DO ANYTHING ABOUT THEM
I can think of one area that seems as if it could be a possible cause of backlash; again, remember that I didn't actually observe any in this specific area. But when trying to turn the close-range adjustment screw (seen in the following picture from Rich C's website) I noticed that the lever on which the screw rides flexed noticeably when I pressed down on the screw. (It helped to support the lever from underneath with the barrel of a screwdriver.)
The lever connected to this screw is one of several long levers that connect the coupling arm in the lens throat to the RF module. They're underneath the module and mostly invisible. Again, note that I did not observe any flex in these levers along the direction they move as you focus, so there is no reason to assume they ARE an inherent cause of backlash. But I could easily imagine that if one of these levers did flex or twist during focusing, it would cause backlash. And if it did, there basically wouldn't be anything you could do about it.
3 - BACKLASH YOU MIGHT BE ABLE TO TREAT
This one is not only speculative, but potentially controversial, because I'm about to contradict something on Rich C's website, and he knows a lot more about this stuff than I do. But to understand my speculations, first look at the following picture of the adjusting mechanism for the RF module:
In this picture you see the now-famous screws for adjusting the RF image focus, infinity position, and vertical alignment. They work by changing the position of the swinging lens that moves the RF image. To make this a bit clearer, I drew a not-very-accurate schematic of the swinging lens and its adjustments:
What I want you to notice is how the RF-focus and infinity screws (the two left ones) work. They are NOT micrometer-type adjustments that work by moving something along their threads. Instead, they are eccentrics -- the screw head turns an off-center portion of the shaft, which rides in a slot in the adjustment plate. As the off-center portion turns, it presses against the slot and causes the plate to move from side to side.
When turning these screws in my R-D 1, I noticed that there was a small amount of free movement before the plate started moving. Obviously, this meant that there was a bit of clearance between the slot and the eccentric section; there'd almost have to be, or the mechanism would have a lot of friction and would wear more quickly.
So, I could at least imagine the possibility that when you reversed focusing direction, there'd be some wasted motion in the adjustment plate until it "took up the slack" in the slots -- unless the screws were sealed to the plate.
In other words -- and here comes the controversial part -- I suspect that the sealer used on the RF adjusting screws is necessary to reduce backlash.
Now, Rich says on his site that the screws have enough friction that they don't require sealer, and for all I know he may be right. As I said, this is speculation.
But my speculation is that if you've removed the sealer from your R-D 1's adjusting screws with solvent, or if you've loosened its grip through too many attempts at adjustment, this MIGHT (again, only "might") be a potential cause of backlash. Without any sealer, reversing the focusing direction would cause the adjustment plate to shift around to the extent of the clearance in the screw slots, until they pressed up against the eccentric screws from the opposite direction.
I just want to emphasize one more time that I am only GUESSING, that Rich apparently thinks differently, and he knows a lot more about camera innards than I do! In other words, I wouldn't recommend delving into your R-D 1 just to re-seal the sealer.
And I also want to emphasize that the RF almost undoubtedly was designed to reduce the risk of this. I didn't take the R-D 1 apart far enough to see, but on other cameras I've examined, the design precludes the possibility of the adjustments producing focusing lash. Typically the whole moving portion -- the adjustment plate, the eccentric screws, and the moving lens frame -- sits on a movable base, and it's this base that turns the moving lens in response to the action of the focus coupler in the camera throat. The adjustment screws move the adjustment plate only relative to the movable base plate -- there's no drag on them during focusing, so there's no reason they should be subject to backlash.
Again, that's the way it should be, and I'm pretty sure based on what little I could see of the R-D 1's insides that its rangefinder is designed to be this way. But I could also imagine that extra drag on the moving lens (not sure where it would come from, but it's a possibility) might get transferred to the adjustment plate and cause it to wiggle enough to produce backlash.
At any rate, after I did mine, I did re-seal the screws (using automotive "thread locker") and if you think my speculations are plausible, you might want to do the same if you have to do a top-off RF adjustment for some other reason. After all, Cosina did put sealer on the screws in the first place, so it's not as if you're doing anything "foreign" to the camera by re-sealing them.
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jim_buchanan
Established
"I'm going back in"
"I'm going back in"
Well, a lot to think about!
I have the vertical and infinity adjustments, OK. However, I am not satisfied with the close focus rangefinder adjustments of my R-D1.
All 3 of my Leica lenses focus perfectly at infinity. My just acquired 28mm Elmarit, current just before the new ASPH. is a beauty. This gives a 35mm focal length equivalent of 43mm, the same length of the diagonal of the R-D1 sensor. The true "normal" focal length of a system is the length of the sensor diagonal, but this is another story...
I have the tabbed Summicron 50mm that has the current optical formula for an effective 80mm. Yes, 80mm, as the true focal length of this Summicron is 52mm.
And lastly, stepping way out there with the 135mm f/4 Tele-Elmarit, just a step down, quality wise, from the current APO version. A mint example went for less than $300, last week on eBay! I am determined to make this lens work at close focusing with the R-D1 camera. I have some outstanding examples of infinity focused photos with this lens.
I have found my R-D1 front-focuses a little with all my lenses, the greater the focal length, the greater the effect. This condition barely effects the 28mm, but the other two lenses require more accurate focusing.
It makes a difference which way focus is approached. In all cases, and most pronounced with the 135mm, accurate focus is from close to focus point, versus infinity to focus point. The backlash, using the 135mm, is almost 6 inches at 6 feet. I have notice that the rangefinder split image converges smoothly toward infinity and stops at infinity. But, when backing off, there is quite a bit of movement, before the the double image moves. Therefore, I think, a lot or a little backlash, focusing from close to focus point is the best technique.
I will be prepping for a second top off adjustment. My hit list is:
1. close focus adjustment
2. reduce backlash in mechanism, per jlw suggestions
3. investigate feasibility of 90 or 135mm frame lines
"I'm going back in"
Well, a lot to think about!
I have the vertical and infinity adjustments, OK. However, I am not satisfied with the close focus rangefinder adjustments of my R-D1.
All 3 of my Leica lenses focus perfectly at infinity. My just acquired 28mm Elmarit, current just before the new ASPH. is a beauty. This gives a 35mm focal length equivalent of 43mm, the same length of the diagonal of the R-D1 sensor. The true "normal" focal length of a system is the length of the sensor diagonal, but this is another story...
I have the tabbed Summicron 50mm that has the current optical formula for an effective 80mm. Yes, 80mm, as the true focal length of this Summicron is 52mm.
And lastly, stepping way out there with the 135mm f/4 Tele-Elmarit, just a step down, quality wise, from the current APO version. A mint example went for less than $300, last week on eBay! I am determined to make this lens work at close focusing with the R-D1 camera. I have some outstanding examples of infinity focused photos with this lens.
I have found my R-D1 front-focuses a little with all my lenses, the greater the focal length, the greater the effect. This condition barely effects the 28mm, but the other two lenses require more accurate focusing.
It makes a difference which way focus is approached. In all cases, and most pronounced with the 135mm, accurate focus is from close to focus point, versus infinity to focus point. The backlash, using the 135mm, is almost 6 inches at 6 feet. I have notice that the rangefinder split image converges smoothly toward infinity and stops at infinity. But, when backing off, there is quite a bit of movement, before the the double image moves. Therefore, I think, a lot or a little backlash, focusing from close to focus point is the best technique.
I will be prepping for a second top off adjustment. My hit list is:
1. close focus adjustment
2. reduce backlash in mechanism, per jlw suggestions
3. investigate feasibility of 90 or 135mm frame lines
mike_j
Established
I have not delved into my Bessa R2 yet, I was wondering how much commonality of parts there is between Bess and Epson Cosina rangefinders?
waldemarski
Member
I haven't pulled the top off my R-D1's yet, but jlw and Rich may be addressing separate issues. If I understand things right, Rich seemed to me to be addressing the question of whether the screw itself would be subject to unwanted turning or whether the inherent friction would keep it from rotating, while jlw suggests that physical clearance around the screw (between it and the slot) is a possible cause of backlash which the sealer could minimize. Of course, if I'm making sense of the photos and diagram (thanks, jlw and others for providing these, Rich for your excellent faq), putting enough sealer or lockthread on could potentially freeze the screw to the slot so as to stop the rangefinder from moving, and that would obviously not be a good thing...
waldemar
waldemar
jlw
Rangefinder camera pedant
waldemarski said:
From the looks of what I saw, I don't think that's likely to be a problem. The sealer only prevents unwanted movement of the adjustment plate, which isn't supposed to move in response to the rangefinder coupling arm -- only in response to the adjusting screws.
This would be easier to describe with a diagram, but schematically the rangefinder's "chain of command" usually consists of:
-- the coupling cam or surface on the lens, which moves in response to turning of the focusing ring.
-- the coupling roller and arm in the camera throat.
-- the lever linkage in the camera body that translates the coupling arm's motion to the rangefinder module.
-- what I'm going to call the "input lever" of the rangefinder module, which receives the motion of this linkage.
-- the adjustment plate, which receives the motion of the input lever.
-- the moving element (lens, mirror or prism) which actually makes the RF image move as the lens is focused.
In this chain, the adjustment plate should be firmly fixed to the input lever, with no motion possible except when you're trying to adjust it. So, sealing the screws tightly to the adjustment plate shouldn't impair the action of the rangefinder, which works by using the input lever to move the adjustment plate and moving element as a unit. Does this even SORT of make sense?
Incidentally, in enumerating all the pieces of this chain (and don't forget that most of these levers also have shafts on which they have to pivot) I hope you can see that there are a lot of places where wear or flexing could cause backlash, and that this is true of any RF camera, not just the R-D 1.
Also, it's worth pointing out that because the amount of focusing movement at the lens is fairly small, and the amount of RF-patch movement at the moving element is typically very small, all this linkage has to be made and assembled with a great deal of precision... which is one reason RF cameras cost more to make than SLRs!
RichC
Well-known
Using gunk to bind precision parts together goes against sound engineering practice, especially in such a high-tolerance precision assembly such as a rangefinder mechanism. There are plenty of mechanical ways that the adjustment screws could be locked to the plate, if Cosina thought it necessary.jlw said:
You might be right, jlw, but I'd be surprised. Personally, I think that the gunk is simply threadlocker, to prevent the screws from turning. And even then it's just a safety net: small screws such as those we're talking about should have enough friction that threadlocking compound isn't strictly necessary(assuming precise machining - which I would expect here), which is why I made the comment on my website that locking the threads isn't strictly necessary (agreeing with tmessenger - on whose post on rangedfinder adjustment a few weeks ago I based my article).
I adjusted my rangefinder last year, and didn't replace the threadlocking compound after cleaning it out (didn't have any to hand), and my camera was fine for several months until I dropped it and had to readjust the rangefinder.
After the second adjustment, I locked the screws with a spot of nail varnish.My camera's never had any backlash that I can discern - focus with narrow depths of fields of inches is identical (ignoring user error) whichever way I turn my lens' focus ring.
However, Cosina thought it worthwhile to use threadlocker, so I'll amend my website. Relocking the screws certainly can't harm anything.
I don't think the R-D1 should have any appreciable focus backlash due to the camera - any in a new camera is a manufacturing defect in my book. It'd be interesting to know what proportion of R-D1 cameras suffer from backlash.
Warning: If you use genuine threadlocking compound instead of nail varnish, note that it comes in several strengths, usually dyed different colours. Use the wrong type, and your screws will never move again! You want the type for instrument screws and electrical equipment, e.g. Loctite Green.
PS: I'm no camera expert - Moto Guzzis are my speciality!
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jlw
Rangefinder camera pedant
One more reassembly tip
One more reassembly tip
It wasn't until today that I got around to reattaching the two front rubber covers to my R-D 1.
I found that when I had peeled them off earlier to remove the top cover, they actually had stretched a bit. The original adhesive grips VERY tightly, and the effort needed to separate the rubber covers from the body had distorted them slightly. The result was that if I just laid the covers back onto the body, the edges didn't fit quite within the recesses provided in the body.
When putting the covers back on, I found it useful to stick them down lightly in position, then heat them with a pistol-type hair dryer. This softened the grips and made them more flexible, allowing me to press inward along the edges and make the covers fit flush with the body recesses. When the covers cool off, they stay put and give a nice, tight fit.
One more reassembly tip
It wasn't until today that I got around to reattaching the two front rubber covers to my R-D 1.
I found that when I had peeled them off earlier to remove the top cover, they actually had stretched a bit. The original adhesive grips VERY tightly, and the effort needed to separate the rubber covers from the body had distorted them slightly. The result was that if I just laid the covers back onto the body, the edges didn't fit quite within the recesses provided in the body.
When putting the covers back on, I found it useful to stick them down lightly in position, then heat them with a pistol-type hair dryer. This softened the grips and made them more flexible, allowing me to press inward along the edges and make the covers fit flush with the body recesses. When the covers cool off, they stay put and give a nice, tight fit.