Today's Photo Minute

The Basics of ISO – Part 2

The Concept:

We learned in Part 1 of this series how important ISO was to getting the appropriate aperture and shutter speed combination in a given lighting condition (that we rarely control). Today, Brian Osborne discusses that when we do use higher ISO’s, there will be more noise (or graininess) in our images. However, since we still will need to use higher ISO values, it is important to know the capabilities of your particular camera when it comes to these high ISO’s. Therefore, the assignment presented helps us to get to know our cameras better.

The Assignment:

Today’s assignment is a great way to know how high of an ISO you are willing to go to and if there is a point where you determine the noise levels are unacceptable. This is great knowledge to have when you get into a situation in the field and have to use the higher ISO ranges.

Find a subject (this can be about anything but you can use a figurine, a camera lens, etc.) in a low lit situation such as your desk, inside your home, etc. It is best to have a dark background because that is where the noise will be more evident. Use a tripod and frame up a close-up image of your subject or even a part of the subject. I would set my camera to A or AV mode and use a lower aperture such as F5.6, etc. Start at maybe 1600 ISO and take a photo, making sure the exposure is good. Then take the same photo at 3200, 6400, 12,800, 25,600 ISO’s respectively going up to the highest numerical value (and maybe even trying Hi 1 or Hi 2 settings if you have them). Then compare the images magnified on your computer screen to determine at what ISO you think the noise becomes unacceptable. My test shots are below:

ISO 3200
ISO 6400
ISO 12,800
ISO 25,600
ISO 51,200
ISO Hi 1