A&P question about exposure and f-stop canon slr rebal g

Discussion in 'Lifestyle' started by ihrs, Feb 22, 2003.

  1. ihrs

    ihrs OT Supporter

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    gonna be out in the desert shootin some pics at night of the hills and stars

    long pics... 30 sec + where should i have the aperture? biggest or smallest? 2.8 is biggest and 22 is small right? thanks
     
  2. bioyuki

    bioyuki Ich habe Angst

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    2.8 is biggest, 22 is smallest.

    If you want a shallow depth of field and a faster shutter use larger apertures. If you want a very broad depth of field (everything in focus) use a smaller aperture and be prepared for long shutters. However, try to stay away from the smallest aperture...the image as a whole will actually lose sharpness due to some optics phenomenon...sorry can't remember what its called right now.
     
  3. ihrs

    ihrs OT Supporter

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    thanks man, ill try to get the pics uploaded like monday
     
  4. Joe

    Joe 2015 :x: OT Supporter

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  5. Jcolman

    Jcolman OT Supporter

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    It use to be on older lenses that the sharpest setting for any lens was typically when your aperture is set to three stops from the widest opening. That meant that for a f/2.8 lens the sharpest setting would be at f/8. However, modern lenses are sharp throughout the entire f/stop range.

    You use aperture to primarily control depth of field assuming you have a choice of shutter speeds. If you're photographing fast moving objects and faster shutter speeds are your priority, then you use aperture settings to control exposure first, then depth of field second.

    Cheers
    Jim
     
  6. bioyuki

    bioyuki Ich habe Angst

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    Vignetting is just light fall off around the edges when shooting at large apertures. Image quality decreases at small apertures because of diffraction.
     
  7. bioyuki

    bioyuki Ich habe Angst

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    Most odern lenses suck wide open because they're almost all zooms now. I would still stop down to at least f/5.6 or f/8 for better images. There will always be exceptions to the rule, ie Nikon's 80-200 AF-S which performs wonderfully at f/2.8, but for the most part stop down a bit.
     

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