Blades covering mirror don't close - help!

Discussion in 'Canon EOS' started by proust, Nov 22, 2008.

  1. If I take the lens off my Xsi camera, the blades covering the mirror don't close and I can see the mirror. The
    camera is turned off and the battery is charged.

    When I first got the camera (a month ago), I remember that they were closing when there was no lens mounted. Any
    idea why they're not closing now?

    Thanks,
    Kunal
     
  2. Seeing the mirrow is normal when you remove the lens. I have no idea what it was you saw before.
     
  3. If I remember correctly I (think) I saw that when the lens was taken out, the camera would automatically spin little plastic blades into place to cover the mirror (and to ostensibly prevent dirt from hitting the mirror). But if the mirror is always supposed to be exposed when the lens is off (which sounds a bit scary to me), then I guess it's not malfunctioning...
     
  4. Maybe what you remember was a body cap, often a body comes with one and taken on & off by ones self. This camera design has not changed in many secades, just take care and be aware of surroundings when changing lenses.. normal :)
     
  5. Unless I misunderstand what you are describing... there are no "blades" covering the mirror when you remove the lens. The
    mirror inside the camera body is completely exposed when the lens is removed - that is normal.

    Dan
     
  6. You have been watching too many programs on the Scifi channel. There are no auto covers for the mirror.
     
  7. Kunal writes, "If I remember correctly I (think) I saw that when the lens was taken out, the camera would automatically spin little plastic blades into place to cover the mirror (and to ostensibly prevent dirt from hitting the mirror)."
    Whatever you were smoking, I want some of that!. Musta been killer sh!T!
     
  8. The blades are the shutter curtain and they're behind the mirror, not in front of it.
     
  9. ROTFHSLOL

    ...khm sorry :)
     
  10. Laugh if you want, everyone, but I think Kunal inadvertently "invented" a feature that could be enormously useful in DSLR design. Imagine the implications! As you twist the lens, protective blades shield the mirror box from air currents and dust. By the time you pull the lens off, the box is completely covered. Then have the "sensor clean" function open the blades for access -- or perhaps have a separate "mirror box clean" function for blowing out any dust that might have made it past the blades.

    Brilliant!

    If this feature were combined with lens/body design that wouldn't draw air through the mirror box (when the lens is zoomed and focused), that would be a winning combination.

    Kunal, that one might be worth a patent. Of course defending the patent against the likes of Nikon and Canon would be pretty tough.
     
  11. Blades are needed in front of the mirror just in case somebody wants to touch the mirror with their oily finger tip. You can wash the blood off later with a swab.
     
  12. Well, at-least I know that the camera isn't malfunctioning. Phew!

    And actually, like Sarah says, the idea isn't all that far-fetched. My simple Sony P&S camera already does that. Granted, a lens can't be mounted on it and so it *needs* to have a protective covering keeping the lens safe but as far as the technology goes, it isn't something that's way out-of-the-box. I live in the rainy pacific Northwest and the idea of changing lenses while I'm hiking in the rain w/o having a basic level of protection to prevent water from getting to the mirror is actually quite unnerving.
     
  13. "the idea of changing lenses while I'm hiking in the rain w/o having a basic level of protection to prevent water from getting to the mirror is actually quite unnerving."

    Well, if I were you, I wouldn't change lenses in sprinkly conditions, unless you're standing under a very large umbrella. Moisture inside a camera is a horrible thing!
     
  14. Wouldn't be too great with rain as the drops would drain inside the mirror box once the lens is mounted. Also, the additional
    bulk and cost of a front shutter would be prohibitive--especially all the repairs of EF-S and other protruding rear element designs as they
    crash through the shutter...
     
  15. It seems like it would be a cool idea to have protective covers over the lens, but really it would only be another thing to break. If it was made of a very heavy metal it would be safe, but way too expensive and would add lots of bulk. If it was just like the little plastic shutters on point and shoots it would fail quickly. I've seen MANY point and shoots with the front lens cover jammed. People would think they were safe from dust, but after a day at the beach the "protective" shutter would be stuck, and the camera would need repairs.
     
  16. No Puppy, there's room. If you think about it, a front shutter could sit back in the mirror box a short distance, so long as the mirror isn't raised. Thus it would clear the lens and the mirror. When the lens is mounted, the shutter opens, creating an opening for the mirror to articulate through it. It wouldn't have to be a robust or elaborate mechanism. Plastic parts would do. So long as people don't get stupid and let sand and water inside, it should be a nice dust barrier during lens changes. Of course this is a moot issue until the manufacturers can devise solutions to the issue of lenses drawing dust through the mirror box. Nevertheless, that's a solvable problem too.
     

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