Leica Iiig repair & common faults
Excellent coverageThe Leica IIIg was the last of the classic screw mount Leicas, built from 1957 into the early 1960s as a bridge model for photographers not moving to the M system. It keeps the traditional cloth focal plane shutter and adds the bright line viewfinder from the M3, but there is no meter and no electronics anywhere in it, everything is spring, cloth and gearing.
Mechanical horizontal cloth focal plane shutter · dual speed dials, fast on top and slow on the front · no built in meter · LTM 39mm screw mount · combined viewfinder with 50mm and 90mm framelines
Common Leica Iiig faults
Leica IIIg shutter has light leaks or pinholes on film
Small bright spots or streaks on negatives usually mean the cloth curtains have worn thin or pinholed with age, letting light through where they should be fully opaque. It is a fabric and rubberising problem rather than an electrical one, and severity ranges from a few faint spots to a curtain that no longer blocks light at all. Check nothing is stored against the lens cap in strong sun, but this one is a bench job either way.
Leica IIIg slow shutter speeds sticking or dragging
If speeds below around 1/30 sound uneven, hesitate, or drag out longer than they should, the slow speed escapement on the front dial has old lubricant that has thickened or gummed up over decades. Fast speeds and B often still work fine because they don't rely on that same governor train. It's one of the most common age related faults on this design and points squarely at the slow speed mechanism, not the main shutter.
Leica IIIg viewfinder or rangefinder is dim and hazy
A dim, foggy or yellowed view, or framelines that have gone faint, is typically the internal beam splitter or mirror surfaces deteriorating with age rather than dirt on the outer glass. It affects how usable the finder is for framing and focusing but doesn't affect the negative itself. Wiping the front and eyepiece glass first rules out simple surface grime before assuming it's internal.
Leica IIIg rangefinder won't focus accurately
If the rangefinder's split or double image doesn't merge cleanly at the point of focus, the internal optics have likely shifted out of calibration through age or a knock rather than any fault in the lens. This shows up as consistently front or back focused shots even with a lens known to be accurate. It's a mechanical alignment issue confined to the finder assembly, not the shutter or film path.
Leica IIIg exposure uneven across the frame
A frame that's darker on one side or shows a gradual band of under or overexposure points to uneven tension between the two shutter curtains, so the moving slit isn't a consistent width as it crosses the film. This tends to worsen at faster speeds where the slit is narrower and any tension mismatch matters more. It's a spring and curtain calibration issue rather than anything to do with metering, since the IIIg has none.
Stuck on your Leica Iiig?
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Try it now ›Scatto is a reference tool for people who service film cameras. It explains mechanisms and quotes service data, but it cannot see your camera at the bench, so verify anything load-bearing before you act on it.