Photography 101 – Part I

Discussion in 'The Chatterbox' started by Lyrt, Sep 12, 2008.

  1. Lyrt

    Lyrt Flash

    This is a photography tutorial I started for Big Ren over at SMF. As per Padron’s request, I’m reproducing it here.

    Photography 101 – Part I

    I wrote this lesson for someone who bought a P&S camera and wanted to understand the very basics of photography without bothering with secret formulas and snobbish jargon. First I’ll explain and illustrate the three basic variables of digital photography (aperture, speed and ISO sensitivity), then I’ll tell you very concretely what you should and should not do with your P&S camera.

    Aperture is the hole through which light is admitted. It determines 1) how much light will reach the image sensor 2) the cone angle of the bundle of rays that reach the sensor which has an impact on the depth of field. In practical terms, the lower the f-stop number (f/2.8, f/4, f/5.6, etc.), the wider the aperture and the narrower the depth of field. The higher the f-stop number (f/32, etc), the smaller the aperture and the larger the depth of field.

    In the following examples, you can clearly see the background goes out of focus when the f number is small (i.e. the aperture is wide).





    Shutter speed is simply the length of time the shutter is open (and the image sensor is exposed to light). Obviously, shutter speed, like aperture, determines how much light will reach the image sensor. It also changes the way movement appears in the picture.
    In the following examples, I first froze the movement of water with a high shutter speed; I then shot the movement of water during one second.


    1 sec.

    Aperture and shutter speed determine the exposure, i.e. the amount of light that falls on the image sensor. If one exposes the film or sensor for a longer period, a reciprocally smaller aperture is required to reduce the amount of light hitting the film to obtain the same exposure. Now if you have a P&S shoot camera, you most likely have no control over aperture and shutter speed. I just wanted you to understand the basic principles of exposure.

    ISO sensitivity is the sensitivity to light of the sensor. The higher the ISO number (ISO 800, 1600, 3200, etc.), the higher the sensitivity, the shorter the exposure required. The lower the ISO number (ISO 50, 80, 100, 200) the lower the sensitivity, the longer the exposure required. Why is it important? Because the higher the sensitivity, the noisier the picture. Look at the following pictures. The amount of light is the same, but the ISO is different:

    ISO 80 (0.6 s)


    ISO 400 (1/8 s)

    ISO 1600 (1/30 s)

    ISO 80 crop

    ISO 400 crop

    ISO 1600 crop

    As evidenced by the photographs, ISO 1600 sucks.

    Morality of Photography 101 – Part I:
    As I said before, you most likely have no control over aperture and shutter speed with your P&S camera. It is supposed to determine with its light meter the correct exposure. However, you can control the ISO of your camera. DO NOT use the auto ISO function of your camera. Set it manually to 50, 80, 100 or 200. Use ISO 400 when there’s not much light and you have no choice. Anything above that will always suck.

    Now let's go further.
  2. Queen of Blades

    Queen of Blades Mistress of Mischief Staff Member

    Moderator Supporting Vendor
    Very nice, Yukio. Thanks.
  3. Baloosh

    Baloosh Duder

    This is awesome -- thanks Yukio!!!!
  4. PalmettoB

    PalmettoB The Old Guard

    Y'know, Yukio keeps saying he doesn't do this for a living...but he should! Thanks for the awesome information, Yukio! You made this stuff make more sense to me in one post than whole BOOKS on photography!
  5. mastermute

    mastermute FatBoy

    Thank you! Looking forward to the coming installments!
  6. Bronco

    Bronco Mac Daddy

    Thanks Yukio, we appreciate your help and skill! :cool:

Share This Page