DHL dropped off a parcel from Italy on Monday and inside was a less than perfect Zeiss Super Ikonta A 531.
The Super Ikonta A 531 was the last 6×4.5 folder from Zeiss Ikon superseding the 530 model in 1936 until its demise in 1953.
This postwar model dates to 1953 and has a Tessar 75mm f/3.5 housed in a Synchro-Compur MX shutter.
Being a rangefinder, the 531 uses a rotating wedge design, as found in the Super Ikonta B and Contessa 35. It’s a shame Zeiss Ikon never used the mirror design of the Super Ikonta III/IV, this would have created a dream 6×4.5 folder….anyhow, I digress.
This little folder is smaller (114x79x42) than a Fuji X100T (127x75x53) and weighs in at 600g with film – a truly pocketable medium format camera yielding 16 frames from 120 roll film.
At £116 shipped from Italy, I wasn’t expecting it to look as good as the eBay pictures led me to believe. Upon opening the box it looked clean but a detailed examination revealed a host of issues.
The lens was fogged with some fungus between elements. The rotating wedge had received an impact which left it a little wobbly. The shutter was slow and there was oil on both shutter and aperture blades. The Albada viewfinder was dirty and the rangefinder fogged.
I decided to remove the shutter / lens assembly and started the CLA process. I checked the carrier plate for squareness to the film plane and found a 1mm tilt in favour of impact area. Obviously the camera had been dropped while open causing the damage.
First off I needed to work out a parallel tolerance for the carrier plate to film plane. I used a optimistic lens resolution of 50l/mm and calculated a depth of focus (at film plane) of 0.137mm at f/3.5 for a image distance of 75mm and focal length of 75mm. I then straightened the carrier plate and achieved a parallel tolerance of 0.06mm when measured at 4 points perpendicular through the carrier plate aperture. The carrier plate aperture only allows accurate measurements to be made on a similar sized central part of the film plane, so if my trigonometry is correct, obtaining a 0.06mm tolerance allows for the wider film plane edge tolerance to be within the calculated 0.137mm.
The next stage was to clean, re-lube and test the shutter. I managed to get the shutter pretty accurate at and below 1/250s, but 1/500s only yielded 1/320s. This is typical of old Synchro-Compurs, since the 1/500s uses a secondary spring that loses strength with age. Anyhow, for my purpose 1/320s is plenty fast enough for ISO 100-400 film.
Next up the lens, a gentle clean got rid of all fungus and internal dust leaving all bar the front element almost spotless. The front element had what I thought was a pin-sized ding, however closer inspection revealed it to be a glass bubble and so shouldn’t affect image quality.
Before re-assembly, I decided to clean the external leather trim and bellows. I used wet wipes to get all the grime out and when completely dry, I applied Lexol to feed and get the suppleness back.
I then reshaped the film door (catching on body shell), removed the film pressure plate to add a felt ring to ruby window (to remove any risk of a light leak) and lubricated all folding pivot points. Fortunately there was very little corrosion, so onwards with the wedge arm repair and assembly.
The wobbly rotating wedge arm was due to an inaccessible support shaft rivet being loose on the arm casing, so the only option was to de-grease the joint and use Loctite 480 to glue the shaft tightly back into position. A couple of pin-head sized blobs of Loctite 480 capillaried into the joint and within seconds it was rock solid. All the gear pivots were then lubricated and the wedge assembly re-assembled.
I then assembled the rear lens element and wedge arm assembly onto the shutter and re-fitted the intermediate block and shims before attaching to the carrier plate and bellows.
The front elements were assembled and camera set up with matte screen (on the film rails) for focus adjustment. Using my XT-1 and trusty Mamiya 300mm manual lens, I tweaked the Tessar’s infinity for optimum sharpness wide open – not surprising this 100 year old design provided good acuity.
Unlike the Ikonta B and Contessa 35, the rotating wedge rangefinder was a breeze to set up. The focus wheel is friction locked by a single screw, so all one has to do is set and hold the lens at infinity, loosen the friction screw and rotate the focus wheel to align the rotating wedges and re-tighten.
The final stage was to set the Albada viewfinder’s frame-line accuracy. I first decided to remove the viewfinder lens and mirror, clean and re-assemble. The Albada is quite a crude device using the reverse Galilean design, whereby frame-lines are reflected off a half silvered front lens and projected onto the scene. A simple design that is reliant upon light to illuminate the projection, hence not so good in low light situations. Adjusting the frame-lines requires no more than loosening two screws and moving the aperture mask to correspond with the projected image at the film plane.
The whole process took about 6 hours and I now have an almost mint and highly revered Super Ikonta A 531. It’s now time to put some film in and test the infamous Tessar.