Photography Cheat Sheet: How to Understand ISO Settings
The ability to adjust your camera’s sensitivity (ISO) is one of the great benefits of digital capture. Unlike film cameras, you can easily change the ISO for each shot, if you wish. But when and why change this fundamental photographic control?
Changing your ISO setting means you can adapt the camera to various situations. This will help you get a sharp, properly exposed image in any environment.
What ISO setting should you use?
As a general rule, you want to stick with the lowest ISO possible, as this will give you the sharpest images. It’s easy in good lighting conditions because your camera doesn’t need a very high ISO setting to capture the image. So if there is a lot of light in the scene, you can use a setting like ISO 100 or 200.
When shooting in trickier conditions, you may need to increase this ISO sensitivity, perhaps up to ISO 3200 or 640000 or even higher. This will give you a faster shutter speed to work with, which will help you get a sharp image.
Image noise, however, is likely to be more noticeable. This gives images a colorful and grainy texture, and it can obscure detail, so you really want to keep this to a minimum.
See also What is ISO?
If you’re using your camera on a tripod, you can use a lower ISO setting than you would normally do, which will help the quality of your images. This is because the camera is not subject to any movement during exposure because it is not held by the user, making longer shutter speeds practical.
To give an example, a sensitivity of ISO 100 may require a shutter speed of three to four seconds in a particular situation. It’s too long to be useful when you’re hand-holding the camera; the result will be a blurry image.
On a tripod, however, you can use this type of ISO and shutter speed knowing that the camera won’t move at all during the exposure. It’s great because it allows you to record moving subjects, such as flowing water or traffic, with a nice blur.
Read more: Three key lessons for every new photographer
Today’s cameras allow you to select an auto ISO option. This allows the camera to choose the best ISO for a particular situation, basing its decision on your lens and shooting conditions, and easily change it from frame to frame.
However, there may be times when you want to override this, perhaps for creative reasons. So it’s good to understand what’s going on.
Save our cheat sheet and make sure you never get stuck with ISO again!
• More photography cheat sheets
• More photography tips