ISO - not the Classified Ads

The past few days, I've covered various technical basics. My goal is to explain how they can be useful for any camera, for any photographer. Today's topic is ISO.

A technical definition for ISO is "ISO sensitivity expresses the speed of photographic negative materials". I don't know about you, but I'd prefer the English explanation, which is:

Higher ISO -> better pictures in low light (because the image sensor is more sensitive)

Lower ISO -> higher image quality, but only in optimal light situations

ISO that is too high -> pictures with high amounts of noise, which may render them unusable

Examples:

Higher ISO speeds:



The first one was taken at ISO 800. I was using a macro lens, so this enabled me to take clean, precise pictures without worrying about camera shake. The second one, however, was taken with a wide-angle lens. The ISO was set at a very high 1600. The quality of this image is lower, but it's for effect - I wanted to show the drama of the storm that day.

Medium ISO speeds:

  

These were taken at ISO 400, with a wide-angle lens. In both cases, it was fairly dark inside, so I experimented with 800 and 400. I preferred these. I didn't want them to look artificially bright.

Low ISO speeds:



In both cases, I had good amounts of light and wanted the best pictures possible. They were taken at 100 and 200.

My advice:

1) Try different ISO settings so you can see the impact yourself

2) Do not go above 800, unless you're doing so for special effects

3) My default for a bright and sunny day is 100

I hope this helps! Till tomorrow!