Widelux Repair F7

This repair and overhaul page covers the Widelux F7, but all models from FI to F7 are essentially the same with minor differences. I estimate this particular F7 to date from the 1970′s, based on the serial number and age of the internal components.

DCF 1.0Disassembly

Disassembling the Widelux requires common camera repair tools, but nothing extraordinary. There are no proprietary fittings to deal with. The tools you’ll need include Cross-point / Phillips screw drivers, flat screw drivers (especially on older models), and a spanner wrench with multiple blades. It also helps to have a tray of glass-covered cannisters for holding sets of related parts. I got a few of these trays in India a few years ago. A Zeiss Contax Sonnar is used as an eye loupe.

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(1) Bottom plate removed

The Widelux bottom plate covers the following functions:

  • Lens turret lower bearing
  • Lens turret travel end-point buffers
  • Film winder ratchet
  • Film winder stop point catch
  • Shutter open/close clutch

Remove the two surface screws on the camera’s front face just below the lens turret. Remove the two screws on the camera’s bottom. Remove the bottom plate. Remove the two brass tubes used to standoff the two bottom screws – They may be stuck in place but should be removed so they don’t accidentally fall out later.

Top Plate

The Widelux top plate covers the following functions:

  • Film rewind & eject
  • Shutter speeds & selection
  • Film winder & shutter cocking

Pull the film rewind knob up to expose the set screw on the inside shaft, and remove this set screw. Remove the rewind knob and its shaft. Use a spanner wrench to remove all other parts of the rewind assembly.

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(2) The set screw under the f-stop dial has been badly stripped and doesn’t extract.


Unscrew and remove the f-stop dial face. Beneath the f-stop dial, remove the set screw that binds the f-stop assembly to the main turret shaft. This set screw is quite long, and must be removed almost completely. Remove the outer ring of the f-stop assembly, leaving only the tip of the turret shaft exposed in an open hole. (The set screw on this Widelux F7 was badly mangled, and couldn’t be removed initially. After re-visiting this stuck screw numerous times, I was able to finally remove it after re-cutting the screwdriver slot under the magnification of an eye loupe.)

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(3) Finally, top plate removed: Shutter speed gearbox is on left, winder gearbox is on right.

Loosen the set screw on the side of the shutter speed selector knob, and remove the knob. It will leave a tiny dimple on the shaft, so you’ll be able to see what speed it’s on when you re-attach the knob later.

Unscrew the film winder dial face, and remove the dial and knob. Remove the screw located on the top plate, just in front of the winder knob.

Remove the top plate.

Lens Turret

To remove the Widelux lens turret, you must first remove the top and bottom plates. Remove the turret top gear (under the top plate). Remove the mounting screws under the lens turret (under the bottom plate). The turret drops down from the Widelux bottom.

Common Issues

DCF 1.0

(4) Film “plane” behind the turret, showing lead idle roller (left), and trailing idle roller (under light gate, right)

On this particular Widelux F7, the two idle rollers that press the film against the film “plane” had become sticky and didn’t turn freely. This can result in scratched film. The roller shafts should be lubricated with a single drop of light oil.

To remove the roller shafts, the Widelux top and bottom must be disassembled. It requires removing the shutter speed gearbox and the winding gearbox inside the top plate, and the winder stop lever inside the bottom plate. The idle roller shafts attach with single screws at each end. When the end screws are removed, the roller and shaft will lift out for lubrication.

If the rollers can not be removed, it is sometimes possible to apply the oil droplet at one end of the shaft, while the roller is mounted in the Widelux.

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(5) Turret end-point buffers: At top, the padding in the home buffer has cracked from age. The cocked position buffer is at image bottom.

Two stop point buffers are installed under the turret, inside the bottom plate. The home position buffer provides a cushion for the turret to hit at the end of an exposure. The cocked position buffer must never be reached – the turret must have a little extra space after the film winder has been advanced all the way. Failure the leave some gap at the endpoint buffer can result in a broken winding gear!

This particular Widelux F7 had a very old home position buffer. The original bumper material had long since cracked and fallen out, so I replaced it with a small rubber block.

Both the home and cocked endpoints must be set where the shutter slit is fully tucked into the body. Inside the film chamber, check the position of the shutter slit when the turret is both at home and wound positions.

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(6) Difficult to photograph, but some of the damaged teeth are visible here. Note the heavy tool marks (left-center), and the “spiraled” teeth (twisted back, right).

On this particular Widelux F7, a nasty problem had developed over time and almost lead to complete failure. The camera had been loosing frames, overlapping frames, and even popping film sprocket holes. Ultimately, the first gear in the film winding train became badly damaged, putting the whole camera at risk due to the unavailability of parts.


The first winding gear, located on the film winder knob shaft, was nearly stripped. Some of the teeth were “spiraled back” due to the stress of over-winding. Because the gear didn’t mesh well with the next gear, winding the film had a “crumbly” feel to it. Some of the teeth were worn down, while others had deep tool marks on the leading faces, possibly from past attempts to straighten the teeth.

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(7) The winder stop lever’s foot blocks the winder shaft with a cam under the gear (to the right). The head of the interfering roller screw is barely visible under the left side of the lever.

But the root cause of this failure was actually on the other side of the camera, inside the bottom plate. A lever is positioned between the turret stop point and the base of the film winder knob, such that it stops the film winder when the turret is fully cocked. This lever was not functioning, because an unrelated screw that holds the take-up idle roller had backed out of its hole and caused interference. With the lever blocked by the unrelated screw, it was unable to click into place and stop the film winder knob. This, in turn, allowed the user to torque the film winder past its designed limit. The shutter release point was over-shot, resulting in missed frames. The first winding gear is badly damaged, as there was nothing to stop the winding shaft.

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(8) Winder ratchet plate removed: Setting final sync for the shutter slit opening. Turret is fully wound, and peg is stopped at cocked position end buffer (lower-left). Winder stop lever is engaged on cam under gear (right).

Widelux parts are basically not available any longer, so we have to improvise. According to one dealer in New York with years of experience in new and re-conditioned Widelux cameras, there are two choices: Find another camera to donate the gear, or attempt to straighten the teeth. But the acknowledged danger in straightening is that teeth can break off – not something I want to risk.

I came to an innovative solution: Reverse the gear, so the spiraled teeth would lean “forward”, and then grind down the leading faces to reach a uniform mesh interval once again. The problem with this approach was that some of the teeth would be reduced to little triangles, but at least they would all be intact. I did that, using tiny files made for watchmaking. This Widelux now works, though it isn’t clear how long the smaller teeth on that gear will last. But since I’m a Widelux user (not a dealer), I know I can just use it gently…

Here’s how the frame winder should be synchronized – This is a loose description:

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(9) Symptom of turret unable to reach fully cocked position: The shutter slit is not fully opened during exposure.

Inside the top plate, remove the first winder gear, by lifting it up from the film winder shaft.

Disengage the winder gearbox from the turret main gear. You do this by loosening the mounting screws on the base of the winder gearbox. Let the turret go to its rest position.

This is the “trigger” position. Turn the trigger gear so that it is just about ready to hold the turret gears (perhaps one single gear tooth from engaging against those gears).

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(10, 11) Reference views of the winder gearbox

Rotate the turret by hand. Observe the moving stud under the base of the turret – It will move out from rest position and allow the stopping lever to swing into place. Turn the winder shaft until the stop lever engages and stops the shaft (inside the bottom plate). The lever engages when the turret’s moving stud is not in the home resting position, so it is necessary to hold the turret forward with your hand. When the lever stops the winder shaft, this is the trigger position. Let the turret go back to rest position.

Inside the top plate, re-insert the first gear, on the winder knob shaft. Re-engage the winder gearbox with the turret main gear, and secure the gearbox mounting screws.

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Verify that everything is in the “trigger” position: The turret is at rest, the trigger button gear is rotated almost to the point of contact, and the winder shaft is in the same position where the stop lever in the bottom plate can stop it (though the stop lever is currently freed by the turret moving stud being at rest position). Also, the frame counter wheel should be just past its point of ratchet advance.

You can now operate the film winder: The turret advances while the film sprockets turn. Near the end of the turret motion, the frame counter advances (if the film back is installed). The stop lever begins to sink into the cam on the bottom of the winder shaft. At the end of the turret motion, the stop lever prevents the winder shaft from moving further. The turret’s moving stud (inside bottom plate) must not press against the end buffer (a sign the winder knob will be under tension later!) The trigger button gear is holding the turret.

Make sure the shutter slit is fully opened during exposure. If it is not (see image 9), this is a sign that the turret is not fully reaching the cocked position. The winder stop lever may be engaging its cam before the turret can reach the cocked position. You can adjust this by removing the plate under the winder ratchet (image 8), lifting the stop cam gear, and re-seating it as necessary to move the stop point. Ultimately, you want the turret peg to reach the cocked end buffer, but not press against it. If necessary, adjust the buffer position and re-apply thread locker to the screw.

DCF 1.0Shutter Speeds

Shutter speed is regulated by 3 weighted clutch cups, inside the shutter speed gearbox. On the Widelux F7, the difference between “125” and “250” is the engagement of 1 or 2 of the higher speed cups at once. A 3rd cup is dedicated to “15”.

These speed cups must never be lubricated. It is a good idea, however, to clean the cups. Remove the top plate of the shutter speeds gearbox, turn the plate over, and clean the cups with anhydrous isopropanol. Re-install the gearbox plate.

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(12, 13) The speed regulator gears, and speed cups.

To prevent chatter, lubricate each gear shaft in the shutter speeds gearbox. Remove the gearbox from the Widelux. Apply a micro droplet of light oil to each shaft, where the end tip pokes through its bearing hole on the outside face of the gearbox. After applying the micro droplets, wipe excess oil from the plate.


Exposure Banding

I suspect there are many possible causes of exposure banding. The most important thing to do is analyze the banding first, with some knowledge of the Widelux mechanisms. What’s the banding interval – is it a slow or fast part of the camera that might be causing the problem?

Uneven banding would indicate chattering of the shutter speed gears. When a gear shaft starts to chatter, the turret speed will slow down and increase exposure.

Even banding, especially at high frequency, would indicate problems in gear meshing. This could be on either side of the turret: shutter speeds gearbox and/or winder gearbox leading into the trigger gear. Gear meshing problems could be due to worn gears, or a gearbox that simply needs to be re-seated.

High-frequency bands would indicate faster moving parts, such as speed cups or speed selector gear in the shutter speed gearbox. Thin bands would indicate gear teeth.

Low-frequency bands would indicate slower moving parts, such as the gears that directly contact the main turret gear (shutter speed side and winder side).

A single area of over-exposure, especially toward the frame’s end, would indicate turret resistance. This could be from a rubbing point on the spiral drive spring, located under the turret main gear (top plate).

A darker leading edge of the frame would indicate trouble in opening the shutter. This is controlled by a friction clutch, inside the turret assembly, under the Widelux bottom plate. Friction is constant, and should be sufficient to open the shutter as soon as the turret begins an exposure.

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