questions, help needed

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  • 03-01-2006, 10:24 PM
    notchicago
    questions, help needed
    I have a question and I can't find hte information so I figured I'd ask those more knowledgable.
    so,
    True or false. A 12 mm fixed focal length lens will give greater depth of field than a zoom lens set at a focal length of 12mm with both lenses having the same aperture setting.

    and

    14. Between what two immediate parts on the camera is the film plane located?
    The shutter and the pressure plate

    also, is there a better way to word this?
    What part of the camera allows the operator to see?
    The entire thing is an automatic eyepiece of which you use the diopter to set each person's eye to, and the rubber eyecup which you see through
  • 03-01-2006, 10:45 PM
    greghalliday
    Re: questions, help needed
    As for the first question. That, I believe, is false. I'm sure some people here will be able to provide you with a technical explanation why, but as my physics knowledge disappeared after undergrad, I won't try.
    Here is a good link to DOF explanation:
    http://www.luminous-landscape.com/tu...ries/dof.shtml


    For the 2nd question. The film is sandwiched between the pressure plate and the film rails. Not the shutter curtains. If the film were to contact the shutter mechanism, it would likely badly damage the delicate curtains.

    3rd. That would be the viewfinder. (inclusive of the pentaprism, focus screen, mirror, finder lens with or without dioptric adjustment)

    Hope that helps
  • 03-01-2006, 10:51 PM
    jorgemonkey
    Re: questions, help needed
    Hi and welcome to the site!

    1. From what I understand (I'm a Photography major now) A zoom lens at say F16, will have the same depth of field as a 12mm prime at F16.

    2. Yes, the film plane is located between the pressure plate and the shutter.

    3. On an SLR, the image you see is coming through the lens, it hits a mirror, and bounces up to a pentaprism, and then shows up in the viewfinder. When you take a picture, the mirror flips up (which is why the viewfinder goes black) and the image is recorded on the film. The rubber eyecup and the diaopter are located where you look through the viewfinder.

    I know there are others here that could probably answer your question in better wording that me :)
  • 03-02-2006, 06:52 AM
    another view
    Re: questions, help needed
    Is this a homework assignment? Guessing by the "14" shown in your original post...

    A 12mm lens at any aperture will give you the same DOF whether it's prime or zoom. There are other reasons why you might choose a prime or a zoom, but the DOF does not change.

    Correct - the film plane is between the shutter and the pressure plate. Wording is fine, I'd say.

    The part that you're talking about at the end of your post is the viewfinder. The parts mentioned are components of a viewfinder (prism, mirrors, diopter, etc) but it looks like "viewfinder" is the word they're looking for.
  • 03-02-2006, 08:15 PM
    notchicago
    Re: questions, help needed
    Hey, yeah actually I'm a film student and I was doing a cinematography study guide-- which was hard because most of the time we practice making film by being given a task to complete, so we never really have sit down and learn class.

    I'd looked all over for answers. Thanks for all of your help.