Camera Basics #1 – ASA & ISO

By Tuesday, April 17, 2012 2 Permalink 0

Recently, one of my cousins asked me to teach him some camera basics. After spending yesterday wandering around San Francisco with cameras in our hands, I realized the same camera basics would be useful to my readers. So…I’m going to start posting some camera basics from time to time.

What does ASA and ISO mean? And, what do they control?

  1. ASA – American Standards Association. ISO – International Organization of Standardization. For all the technical stuff about each process check Wikipedia.
  2. Sometimes you will see ASA, sometimes ISO. The new standard is ISO.

Why should you care about ISO?

  1. It tells you how grainy (film) or how much (digital) noise your image will have. (See the Wikipedia gif above showing the difference between ISO 100 and 3200)
  2. It tells you how light sensitive your film or (digital) camera sensor is. When you purchase film, you look for the ISO rating to tell you what kind of lighting it is made to be used in. The lower the number (ex: ISO 100), the less light sensitive it is. ISO 100 film is great for bright situations – Ex: the beach on a sunny day. Shooting indoors with low light? ISO 3200 may be needed because it is much more sensitive to the small amount of available light.

The same kind of thinking applies when you are setting the ISO on your digital camera. The setting on your camera tells it how sensitive it needs to be to the available light.

Warning! – Do not automatically think, low light…must crank up the ISO. If you like grain/noise in your images, great! If not, it’s time to haul out the flash (and that’s a whole different loooong post) or change your exposure (also a subject for a different post).

I tend to start my (digital) camera at ISO 400 (open shade) and work from there. If the light gets brighter, I may adjust it to ISO 320 or 200. If I head inside and am shooting with window light late in the day ISO 1600 or 3200 may be needed. My best advice is to go play. Try out the different settings and see what you like. If you are just starting out, turn everything but the ISO setting to automatic and see what a difference changing the ISO can make. Now, go out and PLAY!

Small disclaimer: I have greatly simplified this explanation. I apologize to all the wonderfully technical people out there. I unfortunately, am not one them!

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2 Comments
  • Cabbie Notes
    April 17, 2012

    Sometimes it’s good to keep things simple. I hope that your cousin learned a thing or two. Cheers.

    • Melissa Bagley
      April 17, 2012

      Thanks for your post Cabbie Notes – When all else fails, I go back to the K.I.S.S. principle – Keep It Simple Stupid! My cousin got a good start and seems to be confident he can take on the basic stuff alone. He’s already requested lesson number two on posing people!

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