This T90 has notches. . .?

Discussion in 'Canon FD' started by alan_swartz, Apr 23, 2003.

  1. Hello all,

    I have in my hand a T90 that has two small notches filed in the left
    side of the shutter opening. One is square, one triangular, and
    they're located about a quarter inch above the bottom of the
    opening. They resemble the identifying notches in the edges of sheet

    I'm told that Canon service put them there when the camera was
    serviced in 1992, at which time a PC socket was installed. Does
    anyone have an idea why these notches were cut? It seems an odd way,
    and an odd location (in the film path!) to say, "Canon was here!"
  2. Notching the film gate is a common method of distinguishing between different camera bodies or different backs on a camera with interchangeable backs. If you're shooting with more than one body or back and you have a malfunction, the notches allow you to determine which body or back has the problem.
  3. awahlster

    awahlster Moderator

    David so what your saying is the notches expose above or below the normal 24X36 neg to MARK the negitive and therefore ID the neg to the body that exposed it. INTERESTING I had never thought about this before. Kind of a non damaging DATA imprint. But instead of on the image on the edge of the neg.

    Thanks I learned!
  4. That's right. The notches are actually in the border area and not in the image area. This can be done with large format filmholders as well.

    This is particularly important with medium format backs, most of which, even the most expensive, tend to be troublesome on occasion. If you were a pro cycling through 3 or more backs on a model shoot and you found upon receiving the film back from the lab that some rolls had overlapping frames, you wouldn't want to have to run a test roll through every back to determine which was the culprit. The notches let you figure it out directly from the film.
  5. I had my Canon F1N's notched because I'd often shoot with 2 to 3 of the same cameras at a wedding. If I had a flash problem - a cord short out - a light leak or whatever -- I'd know exactly which camera had the problem. My lab actually suggested it years ago when I had a light leak... It really helped later on for other problems mentioned. When you are shooting 700 to 1200 frames a weekend...there is a lot of wear and potential failures. Also why I shoot with 2-3 cameras! Cheers.
  6. I had one of my T90's notched when I took it in to have it serviced so as to keep the film leader from being completely wound into the cassette. Canon Calgary did it about 8 years ago.
  7. Thanks to all. That confirms my suspicion as to their purpose, and I have learned something. The remaining question is why Canon notched it. It is a one-owner camera, whose former owner writes, "I too was a little surprised to see the notches on the left edge. Canon added them during the service to install the PC terminal. I do not know what the reasoning was or what the purpose of the notches is."

    Do you suppose Canon assumed it to be professionally used due to the PC socket installation, so just cut the ID notches as a matter of course? This really isn't an issue at all, just my curiosity.

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