tunalegs
Pretended Artist
What is the Clarus MS 35? A 1940s attempt to build a decent interchangeable lens, focal plane rangefinder camera in the U.S. Although usually regarded as a failure - the camera was in production for six years, and they're not all that rare, so certainly the camera enjoyed some success in the market. The other part of the failure equation is the design though. These cameras had a reputation for erratic to non-functional performance. The design is simple, but there are some "interesting" engineering choices in it.
On the whole the camera is substantially built. Outwardly the fit and finish look pretty good. The camera looks and feels solid. It is also unusually fat. Like Argus C3 fat. And it's weird and inexplicable given how little is actually inside the camera.
First thing I noticed looking under the hood - brass gears - brass bushings - brass bearings. No holding back on the brass for Clarus. The shutter spindles are substantial, the inside looks as big and heavy as the outside - well what little there is inside anyway.
Second thing I noticed was the four "drum" shutter. Not a Leica clone here. More in Common with an Exakta or Edixa SLR shutter. The primary advantage of this design is that shutter speeds can be selected before or after winding without damaging the shutter. However the designers of the Clarus built the shutter dial in such a way that you can't select shutter speeds until the the shutter is cocked, unless you're ok with not knowing what speed you're selecting.
Then something else struck me: The shutter curtains travel different distances. In cameras like the Exakta and Edixa the shutter rollers/drums are laid out so that the leading and following curtains travel nearly the same, if not precisely the same distance. This might be one reason for the Clarus erratic behavior.
This camera needed some cleaning and oil. I didn't want to remove the film gate since I didn't want to have to mess with collimating the lens. A nice thing is that the shutter axels all run through plates screwed into the camera, and this allowed me to peek around a little bit more.
After cleaning and oiling whatever was accessible without getting under the film gate, I began adjusting the shutter tension. First I let all the tension out, then I put on the minimum tension needed to get each curtain to pull fully through its travel. From there it was pretty simple to get a reliable 1/500 out of the shutter. So I tightened everything up, and put the camera together. Only to realize that somehow - the shutter got much faster when I put the camera together.
It turned out that for some reason I don't fully understand, the retaining spring which holds the tension adjustment on the curtains, somehow had the effect of speeding up the shutter when tightened down. Took one full turn off each spring - checked again with the retaining spring fully tightened, and it looks acceptable again.
The shutter fires evenly and consistently at all speeds except 1/1000, which I didn't bother adjusting for.
Other odd design choices: the wind knob is smaller than the rewind knob. The shutter release works by un-meshing the shutter dial control gear from the film transport. When you lift your finger - a gear jams its way back into place to lock them together again (to rewind you hold the shutter button down). The camera body is super unnecessarily fat. The brushed chrome finish reminds me of 1980s soviet rangefinders. the camera is HEAVY beyond all belief really. The film door is cast metal. The top "plate" is cast as well.
On the whole the camera is substantially built. Outwardly the fit and finish look pretty good. The camera looks and feels solid. It is also unusually fat. Like Argus C3 fat. And it's weird and inexplicable given how little is actually inside the camera.
First thing I noticed looking under the hood - brass gears - brass bushings - brass bearings. No holding back on the brass for Clarus. The shutter spindles are substantial, the inside looks as big and heavy as the outside - well what little there is inside anyway.
Second thing I noticed was the four "drum" shutter. Not a Leica clone here. More in Common with an Exakta or Edixa SLR shutter. The primary advantage of this design is that shutter speeds can be selected before or after winding without damaging the shutter. However the designers of the Clarus built the shutter dial in such a way that you can't select shutter speeds until the the shutter is cocked, unless you're ok with not knowing what speed you're selecting.
Then something else struck me: The shutter curtains travel different distances. In cameras like the Exakta and Edixa the shutter rollers/drums are laid out so that the leading and following curtains travel nearly the same, if not precisely the same distance. This might be one reason for the Clarus erratic behavior.
This camera needed some cleaning and oil. I didn't want to remove the film gate since I didn't want to have to mess with collimating the lens. A nice thing is that the shutter axels all run through plates screwed into the camera, and this allowed me to peek around a little bit more.
After cleaning and oiling whatever was accessible without getting under the film gate, I began adjusting the shutter tension. First I let all the tension out, then I put on the minimum tension needed to get each curtain to pull fully through its travel. From there it was pretty simple to get a reliable 1/500 out of the shutter. So I tightened everything up, and put the camera together. Only to realize that somehow - the shutter got much faster when I put the camera together.
It turned out that for some reason I don't fully understand, the retaining spring which holds the tension adjustment on the curtains, somehow had the effect of speeding up the shutter when tightened down. Took one full turn off each spring - checked again with the retaining spring fully tightened, and it looks acceptable again.
The shutter fires evenly and consistently at all speeds except 1/1000, which I didn't bother adjusting for.
Other odd design choices: the wind knob is smaller than the rewind knob. The shutter release works by un-meshing the shutter dial control gear from the film transport. When you lift your finger - a gear jams its way back into place to lock them together again (to rewind you hold the shutter button down). The camera body is super unnecessarily fat. The brushed chrome finish reminds me of 1980s soviet rangefinders. the camera is HEAVY beyond all belief really. The film door is cast metal. The top "plate" is cast as well.
Attachments
farlymac
PF McFarland
Interesting. I always thought the reason most folks hated them was poor build quality. Sounds like maybe they were just slapped together at the factory without regard as to how long they should work. Strange engineering though (such as that shutter release) could have also been why camera repair people didn't like them.
PF
PF
colyn
ישו משיח
After reading your post I'm now going to have to find my old Clarus and see if I can get it running again on all 8 cylinders..
tunalegs
Pretended Artist
I think the problem is just that the mechanics are too loosey-goosey. Compared to say the Exakta shutter, the gears in here are big and the teeth are oversized. This certainly makes for strong mech, and cuts down production time, but it means there's not really the precision needed to get a reliable 1/1000. Any minor change in drag or friction can influence the shutter speed because the gearing is so coarse and the tolerances so huge.
I also noted that the holes for the shutter setting pin are spaced in strange way, very different from the way you see in cameras like the Exakta, Edixa, Praktica, etc. In the Clarus 100, 200, 500, and 1000 are all almost the same distance from each other, which is very curious, as on the other cameras the spaces between holes get progressively larger as the speeds head down from 1/1000. With a mechanism this "loose" you'd think the spacing would have to be "exaggerated" to compensate.
I also noted that the holes for the shutter setting pin are spaced in strange way, very different from the way you see in cameras like the Exakta, Edixa, Praktica, etc. In the Clarus 100, 200, 500, and 1000 are all almost the same distance from each other, which is very curious, as on the other cameras the spaces between holes get progressively larger as the speeds head down from 1/1000. With a mechanism this "loose" you'd think the spacing would have to be "exaggerated" to compensate.
tunalegs
Pretended Artist
While thinking about it some more I think I picked up on the number one design problem of the Clarus shutter. If you look at other shutters of this type, you'll see that the lead curtain is released, then the following curtain is released after the lead curtain has traveled the distance of the slit needed for the selected speed. The following curtain is then "locked" at this slit width and in a way gets a ride with the lead curtain. That is, if the following curtain is dragging or dry - the lead curtain will still power it along. This is why a lot of these shutters will work ok at fast speeds even if they hang up at slow speeds. You can for instance take one of these shutters, and completely relieve the tension of the following curtain, set it to 1/500, release the shutter - and both curtains will still move across the film gate.
The Clarus does not have this. There is no positive connection between the leading and following curtains. The lead curtain travels a set distance, the following curtain is released, and they both travel independently of each other. What this basically means is that the curtains race each other. Any slight difference between the curtains in spring power, spring tension, friction, etc. can cause fade or capping.
The Clarus does not have this. There is no positive connection between the leading and following curtains. The lead curtain travels a set distance, the following curtain is released, and they both travel independently of each other. What this basically means is that the curtains race each other. Any slight difference between the curtains in spring power, spring tension, friction, etc. can cause fade or capping.