Why is my Seiko shutter missing the slow speed assembly?

Discussion in 'Medium Format' started by JLachiw, Apr 20, 2020.

  1. I recently bought a Mamiya C330s with a 80mm f2.8 lens. I've cleaned and serviced these shutters before, so when its slow speeds weren't working, I decided to crack it open. I quickly discovered the issue: the slow speed assembly is completely missing. Is it actually missing, or is this just an new version of the shutter assembly?

  2. I can even see the threaded holes where it should've been . Not like those parts are just kicking around . Peter
  3. Its actually missing.

    At some point in the past, a previous owner harvested the slow speed module to repair another lens they considered harder to find or more valuable than the common 80mm.

    Since its a drop-in module common to just about all the black barrel lenses, you should be able to harvest one yourself from another as-is beater lens with damaged glass. These occasionally turn up on eBay for $40 or so. Look for less popular focal lengths like the 135mm, and defects that would lower the price but have no impact on you (dented filter ring, missing aperture handle, etc). Tho realistically, it may be simpler and quicker to just look for a fully functional replacement lens, and sell this gutted one for parts/repair.

    Unless this is the unusual final 80mm "S" lens from the same era as the C330S (plain black front filter rings with no engraved wording or numbers around the front elements, marked "Mamiya-Sekor-S" on the top barrel). The 80mm S has become rather scarce and sought after as the final C330S and C220F bodies gained collectible status, with prices averaging double what the normal blue dot 80mm goes for. So its probably worth the trouble of repairing an 80 S with a slow speed escapement harvested from a donor. The standard black barrel or blue dot 80mm is easier to find at reasonable replacement cost vs buying a donor for repair.
  4. If those are all the bits you have, there's no speed regulation at all - for any speed.

    All you have, as far as can be seen, is the shutter cocking, release and flash-synch mechanisms, and the drive spring.

    Looks like somebody wanted to emulate a Box Brownie shutter with what's left.
  5. It does happen to be one of those later 80mm f2.8 lens, but I didn't know there was a increase in value for this lens. Also, is there a distinct difference between blue-dot shutters, and non-blue-dot shutters? I found a potential donor Seiko shutter on eBay, but it is a non-blue-dot shutter, are the internals close, if not identical?
  6. Mamiya enthusiasts have been noodling over the blue dot thing forever, with no one yet coming up with a definitive accurate answer for what it even means. Mamiya itself loved to obfuscate, and was never entirely clear on the difference themselves. The only official statement they ever issued was near the end of their willingness to factory service the TLR system, when they said they would not accept lenses without the blue dot for repair anymore.

    Generally speaking, the blue dot infers secondary qualities but has little or nothing to do with the actual shutter design. Lenses with the blue dot are usually (but not always) from the later production runs, usually (but not always) had tighter optical quality control with less of the sample-to-sample variation Mamiya was notorious for prior to the late 1980s, and usually (but not always) had click stops on their aperture rings. Contrary to urban legend, the blue dot does not indicate multicoating or that the shutter is dramatically more reliable. The only lens thought to be multicoated (and even that has not been proven for sure) is the 80mm S.

    Judging by the photo of your 80 S shutter chamber, the mechanism is exactly the same as previous non-blue-dot black barrel lenses. The posts, screw holes and connection to the remaining geartrain appear to match the slow speed module from any other black barrel lens with no incompatibility. Mamiya and/or Seiko were alleged to have vaguely alluded to the blue dot shutter being marginally improved for reliability: if so, it never manifested in practical use (if anything, I've had more blue dot shutters fail than non-BD or chrome shutters). While its certainly possible the 80 S used a unique shutter assembly, I think your odds are 10:1 favorable its the same as the older black barrel shutters.

    A point many don't realize is Mamiya previously used the "blue dot" gimmick decades earlier on the chrome lenses for their Press 6x9 rangefinder cameras. I've had several blue and non-blue press lenses open for cleaning: zero apparent mechanical difference.
  7. One eBay offer later, and my shutter is looking whole again! Seems to be working perfectly as well, and the assembly fit right into place. Thanks everyone for your help!

    mag_miksch likes this.
  8. How did you find it on eBAY ? Maybe the seller has more, and i am looking for a similar one.

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