Seahorse at the Monterey Bay Aquarium, shot at ISO 6400
Aside from understanding aperture and shutter speed, the third most important setting on your digital camera that is important to understand in improving your photography is how and why to use the proper ISO setting for the right condition. For those of you who remember the time before digital cameras when photos were recorded on to film, you probably remember having to decide what speed film to buy for your camera. Common film speeds were 100, 125, 200, 400, 800, 1600, etc. Generally if you wanted to shoot in darker environments, you would need to purchase a higher film speed, usually 800 and higher. However this would result in photos that would be grainy. If you wanted to have sharper less grainy photos, then you would buy a lower speed film, say 100-200 speed range, but would need more light in order to get a decent photo. If you translate this to a modern digital camera, you now have the ability to change that ‘film speed’ or in this case the camera sensor’s sensitivity to light, which functions basically the same way.
Jellyfish at the Monterey Bay Aquarium shot at ISO 1250
The major benefit is that you’re not stuck with the same speed film for an entire roll of film. On a digital camera you can change the film speed, or ISO anytime you wish. Incidentally ISO stands for International Standards of Organization or something like that.
So the point to all this is that when taking photos, it would be a good idea to look at adjusting your camera’s ISO setting to match how much light is available to you when you’re taking a photo. As a general rule, I tend to keep my ISO low at around 100 when shooting in very bright or well lit conditions, (broad daylight or its equivalent). When I’m shooting indoors someplace, I usually have to set the ISO somewhere between 400-800. When shooting in very dark conditions, say at a concert or at night, I’ll typically have the ISO range from 1600-3200
. The great thing about shooting with a decent DSLR is that even at higher ISO settings the photos aren’t too grainy or noisy. If you have an older or lower end DSLR, or are shooting with a smaller compact camera or camera phone, typically you’ll have much more noise at higher ISO settings.
Underneath Monterey Pier - Shot at ISO 400
Normally your camera would take care of the ISO automatically, but I challenge you to switch your camera to Program mode, Aperture Priority, Shutter Priority, or even Manual and play with the ISO settings and see what you get!