DOF preview too dark?

Discussion in 'Beyond the Basics' started by aaronchio, Aug 1, 2004.

  1. aaronchio

    aaronchio TPF Noob!

    Jul 31, 2004
    Likes Received:
    Boston, MA
    Say I am trying to shoot a flower outdoors and nice and sunny day. I decide to go nuts and do f/22.

    Is the suggested shutter speed that I see on the viewfinder the necessary speed to get the flower to look just like it does in reality?

    I am a little confused with all this readings. I know if the reading is for instance 3 seconds and if I do 4 seconds I want to "overexpose" and if I do the reverse I will be "underexposing" (given that the camera is giving me an accurate reading)

    I am also concerned because when I change the f/stops and use the DOF lever the viewfiender gets darkened. It gets a little grayish and more blackish towards f/22... is this how the image is going to look like!?

    Sorry I'm asking all this questions, I just figure it'd save me some films and improve the one I'm working on right now...


    - Aaron

  2. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

    Aug 25, 2003
    Likes Received:
    Lawrence, KS
    Can others edit my Photos:
    Photos NOT OK to edit

    When you look through your viewfinder you are seeing the image with the lens wide open, even if you have it set to a different aperture. When you take the shot, it closes down to the proper aperture. DOF preview closes the aperture down to what you have set so that you can see your DOF. It is also reducing the amount of light coming through the lens, making it harder to see (that's why it normally leaves it wide open for viewing).

    The meter will recommend shutter and aperture speeds to get middle gray. You'll need to look up other posts to get more info on this, I, and others, have explained it many times. Check out the "sticky" at the top of this forum.

    If you leave the aperture the same, and increase the amount of time the shutter is staying open you are overexposing. If you decrease the amount of time the shutter stays open, you are underexposing. 1/30th sec is 1 stop more exposure than 1/60th sec. Everytime you double or half the time it's 1 stop of exposure.

    At shutter speeds longer than 1 sec you begin to run into reciprocity failure, meaning that doubling or halving the time isn't necessarilly 1 stop. You need to read the technical info on the film you are using to see what the manufacturer recommends. It can be different from film to film.

    Read your instruction manual all the way through twice. It's a short book, and will teach you more about your camera than anything else can.

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