Can I change the lens of my film SLR even when a film is loaded?

  • I have a film SLR that is currently loaded with film. I was using a 28mm lens when I loaded the film but recently got a 50mm and I want to use that instead.

    Question is, can I change the lens without exposing the film? I am about halfway through the film so I'm afraid that if I change lens, it will expose and ruin the film.

    The shutter that isolates the film is going to be in the camera body, so changing lenses shouldn't expose the film, unless there is a fault with the shutter (in which case you've probably got bigger problems)...

    Here is an experiment for you: take off the front and rear caps on a lens, hold it up against a light source (**NOT** the sun!!), and you will notice that you can see right through it. That's how it appears to the camera when mounted, too. As has been said, (in a SLR) it's the shutter (and to some extent the mirror) which protect the film (or sensor) from inadvertant exposure, not the lens.

  • Imre

    Imre Correct answer

    9 years ago

    Yes, you can. Changing lens won't reveal the film in an SLR; both mirror and shutter are in the way. The lens mount is only meant to pass light to the film during exposure — you can see light through the lens in the viewfinder when composing, but that light doesn't reach the film.

    " is never meant to be passing light only" I'm not sure what you meant there... did you mean to word it that way?

    @chills42 It makes sense to me. If the lens mount was *not* "never meant to be passing light only during exposure", it would *be* meant to pass light *only during exposure* (of the film). If so, you would need a separate viewfinder lens (even if trivial), which goes against the concept of *single lens* reflex (SLR).

    To put that another way, if allowing light through the lens mount would expose the film, you'd never be able to remove the lens cap.

    @Blrfl Sure you could, you'd just have to be really quick in putting it back on!

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