Rittreck Six 6x6 SLR. 12 frames per 120 roll/24 per 220. Fitted with 80mm Rittron f/2 lens.
The Rittreck Six was the progenitor of the better known Norita SLR, but was manufactured by Musashino Kōki.
By all accounts this one is virtually unused. I find this easy to believe, because it's become fairly obvious to me that, at the time of its assembly, Musashino Kōki's quality control left a bit to be desired, unfortunately. So its proud owner's first roll of film through this camera would have been a profound disappointment. This Rittreck was sent to me to by its owner in order to get it to actually work properly. On arrival, it had any number of faults. Frame spacing was inconsistent, and the shutter curtains were poorly adjusted because there was considerable tapering across the gate at the faster speeds. The back closure was a little on the loose side (causing other issues with the counter reset and frame spacing), and its Rittron lens would focus beyond infinity by an unacceptable amount (subsequent checks confirmed it had been assembled with the back focus out of spec).
It's an unusual mechanism in as much that it relies on the correct amount of friction in a few places in order to achieve satisfactory frame spacing or indeed, to get the shutter cocking and advance working together at all. I can't help thinking a Rollei type approach to integrating wind release and lock into the counter dial, so that the lever (or knob in the case of a Rolleicord) is either free, or blocked, depending on the counter position, is a much more elegant (and reliable) solution.
The back door closure is a key part of getting the plot to come together correctly. A reset tab inside the top door slot not only resets the counter to "S" but also kicks the film roller into action when you begin advancing to the first frame. If the tab is not firmly depressed by a snug door, or the linkages inside the bottom cover of the body which are driven by the tab's lever are incorrectly adjusted with the wrong play or orientation, the framing may be haphazard or even non-existent (the shutter may not get cocked at all). At various points of problem solving the mechanism I had the frame advancing without cocking the shutter, and the shutter cocking without winding on the film. It's a Goldilocks mechanism. Has to be just right, in order to function sweetly. Nevertheless I got there eventually and it now produces 12 beautifully even frames on a roll of 120.
The shutter is now exposing the gate consistently even at its 1/500 maximum speed. After first cleaning and lubricating the mechanism, this was achieved by increasing the second curtain tension to reduce the tapering across the gate. The alternative would have been reducing the first curtain tension (or I suppose a combination of both). But the first curtain must activate the timing levers, and as medium and slow speeds were still OK, I judged it better to speed up the second curtain to get them balanced across the gate.
It's not a particularly well understood point—but you do actually need a slight amount of tapering of the slit across the gate if the fastest speeds of a focal plane shutter are going to be really good. This is because the curtains are still gathering speed as they travel across the film gate. Because the far end of the gate is thus, exposed for a shorter amount of time, the width of the slit between the curtain ends needs to enlarge fractionally during the run, in order to negate the underexposure that will occur from the curtains accelerating.
I had to estimate the amount of taper needed to achieve consistent exposure by eye using a CRT screen. On receipt it was clearly grossly excessive with the slit tripling in size from side to side, or more. I moderated this to around a 1/3 increase from right side to left side of the gate (as viewed from the rear). A test roll with several 1/500 & 1/250 images featuring lots of clear sky indicates that exposure is very even across an entire negative, so my adjustments were fairly reasonable.
The 80mm Rittron f/2 lens seems reasonably sharp and after the addition of a 0.25mm shim behind the optic module, is now focusing only to infinity at its stop.
See here for more information about the Rittreck/Norita series.
Here's a look inside parts of this 6x6 SLR.
This image offers a little insight into why the Rittreck and Norita SLRs can sometimes manifest inconsistent film advance faults. Eg Winding off a whole roll without engaging the shutter drive. Or perhaps not spacing 12 consistent frames on a roll of 120.
The designer of this camera (whoever that might have been) elected to make life a little harder for themselves (and those of us who try to repair these things many years later). All of the film advance and shutter cocking gearing is located on the right side of the camera body underneath and around the wind lever. This is fine in itself. But like many other roll film cameras which feature automatic film spacing and integrated cocking of the shutter, when to begin arming these, and when to cease same, is triggered by the film counter system. In itself, fine, too.
But...the film counter mechanism is located on the top left hand side of the body, and this is an SLR which features interchangeable viewfinders. A waist level finder was also provided. Also available was a very nice pentaprism finder, which this camera also came with, but, that has been sent on a very long journey from Australia to Blighty, because it was showing signs of de-silvering.
So...you are beginning to see some complications here. How do you make the counter that "switches" on and off the film advance and cocking, communicate with said sub-systems when there is a finder installation in the way? You design linkages that: travel down the left side of the body (via a counter rest lever inside the top door slot, if you please); then, across the underside of the mechanism, before; venturing up the wind side of the body, via a roller clutch switch, mind(!); until (finally) they can engage, or disengage, the gears for the film advance and/or the cocking. At the risk of understatement: this is the long way.
Surprisingly, perhaps, this elongated and indirect design does actually work, sometimes. But only if all of those connections are optimally adjusted with the minimum amount of freeplay. Too much slack in the connections, and strange things happen.
This particular example was basically a brand new camera. It had either not been used at all, before my friend acquired it; or it had seen a roll or two at most? It would not have been any more than that, because, when I received it all manner of adjustments were badly made, if at all. (No, I don't understand why, either).
Apart from incorrect balancing of the shutter curtain spring tensions and a poorly assembled 80mm Rittron, a key issue with the unpredictable behaviour of its film advance was excessive play in the aforementioned connections. The back door latches were working but not as tight as they might have been. This matters because if the counter reset lever the door depresses is not moved far enough the pivoting lever I have circled in red to bottom left will not have rotated enough to move its counterpart (also circled in red at top right).
This is a problem, because the top right lever is connected to a roller to the right of the film gate inside the back of the camera. This roller, which is directly driven by the film rolling across it, is responsible for engaging the lever to activate the cocking gears. The roller won't trip its associated lever near the wind gears if that lever in red has not been moved far enough. If the wire links and the pivot levers are not biased appropriately, the relevant levers do not kick in and film will be wasted.
As well as gently tweaking the shape of the door catch lugs to encourage tighter closure of the door and inspecting the counter parts, a breakthrough (after much winding of waste 120 rolls with all my digits pressing and pulling connectors and levers with the door open), I was able to establish that *if* these were resting in the correct relationship to each other, the plot would fall into place. Some minor shortening of the long wire across the top of the underside in this image was needed, tighter bends to its end corners etc. Also, backing off the securing screws for the two pivots in red, and rotating these on their shafts slightly, to increase the tension they would apply to the next point up the line. Finally...success. It all worked and the cocking engaged and disengaged (at the end of the 12th frame for winding off the paper).
Shutter speed selector peeks out behind wind lever in this image with top right side cover removed. Inside that stack of gears and ratchets is also a roller bearing clutch that, when engaged, will drive the cocking. To far right is the shaft for the dial that disengages film advance, permitting cocking only, should multi exposures be desired. A roller in the film take up area triggers the levers in front of the lower gear in this image which engages the drive to cock the shutter. The levers are also controlled by the counter reset lever inside the top slot for the back door, and the position of the film counter at the time.
Rittreck Six Mirror Release Lever
This lever holds back the mirror (which is ready to lift in this image of the lower mechanism with the shutter cocked). But on its arrival, the mirror would occasionally pre-release during the winding process. Reason? Incorrect adjustment of the profile of the lever with driver tip. It was not angled correctly downwards for best engagement with its counterpart (the raised tab on the longer lever underneath). I had to apply a gentle double bend to draw the hook closer to the tab, but also bend it back parallel to the long lever underneath. After a couple of gentle adjustments, it now works faultlessly with even the most vigorous winding of the lever.
Rittreck Six Viewfinder components.
Left to right:
Top securing frame for screen elements;
Condensor lens;
Focus screen proper;
Screen mounting frame.
Cursory examination suggests all of these can go in any orientation around the clock. Umm...no. Not all. If you service one of these: note which way *up* the parts are *and* which edge faces the front.
Rittreck Six Focus Screen Mounting Foam.
After removing the parts in the previous image this is what I found. Some very old sealing foam already crumbling into black gooey dust. The foam does not contribute to the accurate location and positioning of the focus screen. It's only there for dust and light exclusion. (And to dirty one's focus screen when it ages, apparently).
Looks a bit better now.
Note synchronisation wire for flash socket just visible inside rear foam slot. Don't break this if you are cleaning out your camera foam!
Rittreck Six Focus Screen Mounting Foam
New sealing foam cut roughly to size and teased in situ. Far better than its predecessor: it's good enough.
The focusing and optic modules have just been separated in this image.
Surprisingly, the focus ring still felt fairly smooth, but Musashino Kōki quality control left a lot to be desired when it came to lens adjustment. I talk about how I solved this in the following image...
Focus Module Of 80mm Rittron f/2.
Camera film plane and focus screen planes of focus matched well when I checked these. This lens however was reaching infinity focus well before its focus ring would reach the infinity stop. Only one possible explanation existed: the lens itself had not been correctly calibrated.
This was easier to remedy than might appear to be the case. I painstakingly inspected a distant target with the aid of high powered loupes until sharpness could not be bettered. I then noted, very accurately, the precise setting of the focus ring at this point.
Having done this I was then able to take some depth measurements of the lens in that focus position with a digital gauge. After repeating this measurement with the focus ring on its infinity stop, and subtracting the second measurement from the first, I obtained the dimension of the shim needed to set the optics further out from the body (which would thus prevent the lens from focusing past infinity).
Luck was on my side for a change because this dimension as it happened was exactly 0.25mm, and I had on hand some sheets of mild steel shim stock of just this thickness.
In this image you can see the hand cut shim washer I have made from a piece of 0.25mm shim sheet. A full circle washer wasn't possible due to the lens key way. It also had to be drilled precisely to accept the securing screws which unite the two modules.
After re-assembling the adjusted lens, distant subjects are now beautifully sharp precisely at the infinity stop, as checked optically through the viewfinder, and also with test images.
Speaking of images.
