7D Shutter

Discussion in 'Canon EOS' started by ed_kubacki, Sep 2, 2009.

  1. Has anyone found what Canon rates the shutter life on the 7D at? I looked through the specs sheet but I can't find any info on the estimated shutter life.
    I've worn out the shutters on my 20D and 30D (can my 40D be far behind? :)). I was wondering if it would be greater than 150K.
  2. it's 150K
  3. 150,000 per, whatever that means.
  4. @Harry
    Good question. Just saying 150,000 is completely meaningless unless the testing method and definition of life are given.
    The life could be the average number of actuations of a group of shutters all tested to failure. This would mean that some could fail at 1000 and some could go on to 200,000.
    It could be the number at which 50% have failed.
    When engineers calculate the life of rolling element bearings they talk about L10, that is the point at which 10% will have failed.
    I do not understand how Canon can get away with stating life figures like this.
  5. Thanks Bob.
    I missed it in the preview. Silly me, I thought it would be on the spec sheet from Canon under the shutter section.
  6. Henry,
    150,000 (or any such shutter rating) is a Mean Time Before Failure (MTBF) value.
    We don't know how many shutter assemblies they test or how they test 'em, but they run some unknown number of shutters until failure, average the result out, and there's your MTBF value.
  7. Keith,
    I've evidently missed something because I've not seen Canon ever say it's an MTBF. Can you give me a link to the Canon document that states that the shutter life is the MTBF?
    Surely you'd have to run the entire sample to failure to get a true MTBF; otherwise it's going to be an underestimate? I suspect they run a number of shutters in an accelerated life test until some have failed and then statistically extrapolate a life figure.
  8. I suppose it could even be an overestimate if the sample has a high number of premature failures, Henry, but you make some fair points there, and yeah, I imagine that there's extrapolation.
    I've seen nothing so far explicitly referring to the 7D's figure as an MTBF, but I have certainly seen it in relation to the 40D and 50D.
  9. I don't think Canon's marketing people know what they're talking about. The Canon US website says fir the 7D:
    "Magnesium body with shutter durability up to 150,000 cycles and exclusive dust and weather resistance. The EOS 7D is constructed of the highest quality materials, to exacting standards to ensure unfettered performance at all times. For example, the shutter can shoot at speeds up to 1/8000 sec. for 150,000 cycles; the chassis is built of lightweight and rigid magnesium, and the camera's seals are built to resist water and dust. This combination makes the EOS 7D ready for anything."
    So in the first instance they're saying "up to 150,000 cycles", which means it could fail at 1,000 or it might go on to 150,000 but no more. Then in the second instance they say "1/8000 sec. for 150,000 cycles" which implies it will last 150,000 cycles.
    No wonder I'm confused!
    Furthermore I don't understand why they don't allow us to see the actual shutter actuation count. It's there in the memory but inaccessible in most digital EOS bodies.

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