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Setting aperture manually for automatic speed calculation?

Discussion in 'Adapted Lenses' started by greg57, Aug 6, 2010.

  1. greg57

    greg57 Mu-43 Regular

    43
    Aug 6, 2010
    Istanbul
    Gregory Dziedzic
    Hello !

    Just received my SLRMagic 35mm 1.7 and experimenting with it...

    So... "shoot without lens" mode...... OK
    Do all the settings directly on the lens.....OK

    Aperture automatically displays as 0.0......OK........Hey wait! Wouldn't it be cool if we could tell the camera what the aperture of the lens is so it could calculate the speed for correct exposure in aperture priority mode? Have I missed something? Is it possible? Otherwise how do you do to get correct exposure? Trial and error?
     
  2. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Your camera doesn't need to know the aperture of the lens to calculate the exposure automatically. That's just there for your display, and for you to control. The camera calculates the exposure value based on knowing how much light is hitting the sensor based on calibrated factory values. Modern cameras are constantly metered, so you never have to guess the correct exposure.

    If you're in 'A' mode with a non-native lens, the camera adjusts the shutter speed automatically as you manually adjust the lens aperture in order to meet whatever EV you set. That's it. In 'M' mode, the EV adjusts as you adjust the individual settings to tell you how far off neutral exposure you are as you adjust those settings.
     
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  3. greg57

    greg57 Mu-43 Regular

    43
    Aug 6, 2010
    Istanbul
    Gregory Dziedzic
    Indeed!

    Yes I can see you're right now thanks. :) The thing is it's like always underexposed by 1 stop or so, hence my surprise... ;)
     
  4. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Some cameras do that. That's why the histogram is so useful to see while you're composing. It allows you to adjust the EV appropriately to match the lighting you want. I've heard people say to 'expose to the right' for some of these cameras, which would match your experience with underexposed photos. Try setting your EV to +2/3 or something and see if your photos comes out properly exposed to your liking. As an aside, I can't say I've experienced these issues on my GH1.
     
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  5. bkn42

    bkn42 Mu-43 Rookie

    13
    Jul 16, 2010
    Arizona
    Expose to the right

    A little off this thread's topic, but:

    "Expose to the right" refers to a technique that maximizes the dynamic range of the camera's sensor when shooting RAW images (I think it is not as useful when shooting JPG). Check out this link.

    (Might be more exact to say: its a way to maximize the signal-to-noise ratio in your final image by using the most of the camera sensor's dynamic range -- but this makes me sound like a nerd (which I am, :smile:))

    Brian
     
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  6. greg57

    greg57 Mu-43 Regular

    43
    Aug 6, 2010
    Istanbul
    Gregory Dziedzic
    Geeks rule! :thumbup::tongue:
    (thanks for the detailed answer to you two guys)
     
  7. greg57

    greg57 Mu-43 Regular

    43
    Aug 6, 2010
    Istanbul
    Gregory Dziedzic
    Ok but...

    ...it's not doing this when I shoot with my other lenses as far as I've noticed...