GW690III Notes
The GW690III is big, I literally started laughing when I opened the box it came in because it's just a rangefinder but feels like twice the size of a 35 mm one. It definitely attracts attention in public, probably because people look at you and think you're really small next to it.
The lens is a 40 mm equivalent, a pretty common rangefinder focal length and suitable for group portraits which I'm told was the main use of this camera originally. It's not a bokeh king at f⁄3.5 and 1 meter MFD, but don't rule it out entirely.
Handling & Ergonomics
While the "twang" of the shutter is reportedly caused by the frame counter, some more recent investigation has indicated that this isn't the case, and there is at present no known "hush kit" or "silent mod" for this camera.
I found the aperture to be quite strongly clicked, while the shutter feels fairly standard for a mechanical leaf-shuffter. I didn't find accidentally moving one instead of the other to be a common issue, and I primarily use the shutter ring for fine tuning exposure and leave the aperture alone.
I like the rangefinder, it's 0.72x magnification feels pretty roomy, and the split image while not insanely bright or large looks very sharp to my eyes. The effective baseline length of 59 mm is comparable to most Leica M cameras. The framelines don't move as such but rather grow from the bottom right as you focus, a neat trick!
The shutter will not fire unless you have the door open, or you've completed the film loading sequence and aren't at the end of the roll as set by the roll type selector prior to reaching the final frame.
This magic interlock works by using the drum near the takeup spool, which is rotated by the film or backing paper dragging across it. The frame counter is driven by this rotation and not the takeup spool rotation. The GW690III has a double-stroke wind, and the length of the second stroke is actually variable, stopping when the drum has rotated far enough to advance the frame counter.
As a consequence of this, the frame spacing could in principle be more correct (the film movement vs. spool rotation is not constant, obviously). The first frames will have a longer second pull than later ones since the takeup spool will be thinner. In practice I do see slight inconsistencies in frame spacing (some frames farther apart), but the margins for a 120 roll of 6x9 are quite lenient.
I'm not in love with the flat wide strap lugs, they only really work with flat cloth straps (the kind shipped with most SLRs) or with those tiny cords at the end which feel a little weak.
Canon Speedlite 580EXII is my preferred flash gun for a camera this size. With C.Fn 05 set you can very easily enter your aperture & ISO and it will do automatic exposure. Note that since this camera is fully mechanical, any flash will work, even those with high voltage triggers. The camera synchronises at all speeds, which is great!
Shooting 35 mm film?
Doesn't seem to be super easy unfortunately.
Some discussion here: https://www.flickr.com/groups/fuji-gw690/discuss/72157632646668589/
An article on making a "TEXpan" https://emulsive.org/featured/how-to-make-a-texpan-shoot-wide-format-35mm-film-in-the-fuji-gw690-rangefinder
Of note, this article suggests taping up the drum up to make sure it grabs the film properly. Also noted is a recommendation to tape a bit of extra film-leader or backing paper on to avoid wasting film during loading.
Zluxtech makes a panoramic adapter frame https://www.zluxtech.com/store/products/fujifim-gw690-panoramic-kit-35mm-to120-adapter-can-suit-all-version-fuji-690 but no instructions are available. Not sure if this would solve the loading issue, or if additional leader would be required.
It seems like it would be pretty simple to put some kapton tape over the frameline mask to colour in a 35 mm sub-frame, if you wanted to use the camera like this regularly. It's accessible with the top cover removed.
Service
The service manual is available! https://archive.org/details/central-manuals-camera_fuji_gw-gsw-690iii-sm-en.pdf
Rangefinder adjust
I started adjusting the rangefinder due to slight misalignment, but later found I had a more serious issue. Note that adjusting the rangefinder may be required sometimes, especially if knocked around.
My assumption with this adjustment was that the infinity stop of the focusing ring was still set correctly, so a simple infinity alignment would be sufficient. The manual has a proper procedure, which also has to be done at a shorter distance to ensure the rangefinder apparent movement matches the actual focal length of the lens.
Top lid removal: simply unscrew the film advance lever (mine was removable without tools), then remove 4 screws (PH00) and pull. One screw is hidden behind the film door, so you can't do this with film in the camera; with 6x9 film in the camera is a highly temporary problem so don't worry. The rangefinder cover sheet uses smaller screws and needs a PH000 driver.
Rangefinder vertical adjustment is easily done using a 1.5 or 2 mm flat head screwdriver, only the top lid needs to be removed but pulling the plastic sheet over the rangefinder helps with access. Adjust screw 5-27 (behind mirror).
The rangefinder window mirror is used for both vertical and horizontal adjustment; it's a fairly precise mechanism with little cross coupling and so is easily adjusted.
Horizontal adjust needs a 2.5 or 3 mm flat head, loosen the locking screw (not shown in figure) first then turn the eccentric pin (5-18, has + shaped slots). You can look through the rangefinder for both adjustments, but make sure you're looking at objects preferably 500+ meters away (a block or two away is too close!). This mechanism is fairly stiff, make sure you use the right (big enough) screwdriver to avoid damaging the eccentric pin.
There is a lens that actually moves the overlay image on linear rods with an anti-backlash spring. This movement can be a little sticky, manifesting as a delayed motion of the split image. I added a tiny amount of machine oil to the rods and cycled the focus back and forth. This seemed to resolve it, it's easily done with the top cover off.
Curiously it seems the rangefinder optics themselves were not considered serviceable, most of the elements seem to be glued in place and the figure above shows the entirety of the parts breakdown. Most parts inside it are glued in place.
Shipping damage to viewfinder
My unit arrived with shipping damage, in the form of the entire prism that forms the actual viewfinder being mostly loose. This square block of glass is glued to the bottom of the rangefinder, and has a flat blade spring on top that I think just held it down during manufacturing while the glue set (visible in the figure above).
Due to this only being held in by the spring, it was free to shift around and the rangefinder alignment went off as soon as I put the camera down.
I resolved it by epoxying it back in place, making sure to align it as best as I could to give a good rangefinder image and tightening the blade spring to hold it in place. Epoxy is a good choice; do not use super glue as that is almost guaranteed to fog the optical surfaces.
I used Araldite 2012, but many types of rapid epoxy are likely suitable; avoid anything with strong solvent smells since those are more likely to fog lenses.
Hotshoe-cable
During handling the flash-sync cables are easily damaged, especially since they're quite short. (Do make sure not to get them entangled in the frame counter if you lengthen them).
Re-soldering the connections I ended up with a slightly taller joint than before, this interfered with the plastic cover over the rangefinder when the lid was reinstalled.
This then led to the vertical alignment of the rangefinder noticeably shifting when I had to force the top cover down to get the screws in, not acceptable.
So make sure you don't add any height, there isn't much vertical clearance between these components.
Aperture tabs
The aperture tab thing was broken on one side, this is just a screwed in piece of plastic. A 3D printed replacement was acquired (https://www.thingiverse.com/thing:5451317) and printed in PCBWay "PWR Dark Black" resin. I opted to replace both sides.