You've never heard of ISO?

ISO stands for the International Organization for Standardization (no, not IOS) and it is a unit of measure for something called "film speed."

Remember that a photograph is just light "written" onto a light-sensitive material (see "Write with Light")? Now, film speed tells us how light-sensitive a material is.

  • Do you want something to be more sensitive to light? Use a higher ISO.
  • Do you want something to be less sensitive to light? Use a lower ISO.

ISO is rated with numbers traditionally ranging from 100 to 3200. However numbers lower than 100 have been around since the days of film ditto to numbers above 3200. With the advent of digital camera sensors, ISO numbers have well exceed 3200. Even as high as 4,560,000! Remember that higher ISOs are have better low light capabilities. This means that modern cameras can capture images in extremely dark environment.

ISO 400 is a "normal" film speed. It is an all-round film speed for an average day outside. Normal here means, a bright sunny day.

Kodak UltraMax is a pretty popular ISO 400 for 35mm film cameras among beginner photographers. Kodak's Portra 400 and FujiFil's FuijiColor Superia X-TRA 400 are also great options. However, it boils down to personal taste.

The same goes for digital cameras. Each brand and each camera sensor has its own characteristics and picture quality. Experiment and find one that works for you!

Kodak UltraMax ISO 400

ISO brings along something called "noise." Noise is that "grainy" stuff on images. It's what gives low quality images its--well, low quality! As a result, we typically use the lowest practical ISO for our pictures. this will give us the best quality. However, we don't live in a perfect world. We often have to raise ISO higher than expected. Then we have to adjust things like shutter speed and/or aperture.

For now, we know that images are captured on light-sensitive materials. Some materials are more sensitive than others and this will be known by its ISO number. Digital cameras have multiple ISO numbers thus its sensitivity is customizable.

Practice taking pictures at different ISOs.