Many of you know that we offer a lot of digital photography related classes at the Computer Education Center in Lincoln, NE. One reason is because we, ourselves, just love photography, and have for a very long time. And there’s nothing quite as fun as sitting around with other folks who enjoy the same hobby, and pass tips and tricks back and forth.
In our digital photography classes, and specifically, in our “Using Your Digital Camera” class, one of the favorite tips we pass along has to do with taking a decent picture in low light, when you’re too far away to use your flash.
First of all, you should know that we do NOT like the flash. Sure, there are times when you really need it and have little choice but to use it, but we still don’t like it. The problem is, flash often leaves the subject of the picture looking flat and uninteresting because the light from the flash has removed important shadows that help give depth. In addition, flash in an image that is not properly exposed can wash out parts of the subject (glare), and create new, unsightly shadows on walls and other objects.
Here is an example. In the picture on the left, we’ve used a flash. Look at how the face is washed out (no shadows), but behind the subjects you can see shadows on the wall that are distracting. In the picture on the right, we’ve turned the flash off and the subject is being lit from a window to the side. We now have soft, facial shadows, that give the subject depth.
Can you see why we don’t like flash very much?
And still, flash is often a necessary evil when there just isn’t enough light on your subject. Or is it? And what if you are too far away to use the flash, which is typically only good out to about 10 or 12 foot?
That’s where this great thing called ISO comes in.
ISO (which stands for International Standards Organization, which tells us nothing about what it really is), is a measurement of how light-sensitive the digital camera light sensor chip is.
ISO has been around since the days of camera film, and in fact WAY back was called ASA. But even with film, it measured the same basic thing… how light-sensitive film was.
ISO is indicated by a number. The higher the number, the more light-sensitive the film or light sensor is. Typical numbers are 50, 100, 200, 400, 800, 1600, 3200, 6400, and even higher. What this means is, as you increase the ISO number, your camera becomes better at taking pictures in lower light, without having your pictures come out blurry because of a low shutter speed and camera-shake.
NOTE: Although I don’t want to get into a big discussion about shutter speed and aperture right now, the two camera features that determine the exposure of your picture, I at least have to mention something about shutter speed, since it’s related to why we need the higher ISO.
In order to get a proper exposure in low light situations where you can’t use the flash, your camera automatically lowers the shutter speed. If it drops too low, your pictures get blurry because of camera movement or subject movement. As a rule of thumb, you need to keep the shutter speed above 1/60 of a second.
So, as you increase the ISO (increase the light sensitivity of the camera chip), your goal is to get an ISO that’s high enough to get the shutter speed above 1/60. Once you do that, you’ll have less blur in your low light picture.
But there is a draw-back. As the ISO increases, noise (on film we call it graininess) is introduced. How much noise? Well, it depends on a lot of things including the subject and even the quality of your camera sensor chip. But the good news is, even though noise is introduced, raising the ISO in low-light situations where you can’t use the flash at least lets you get a picture that you otherwise would not get.
For example, here’s a picture taken of my son Jack at an indoor sports facility that was poorly lit. I was too far way to use the flash, and was actually using a telephoto lens. But by increasing the ISO to about 1600 (in this case), I was able to get a picture. It’s not perfect, but certainly good enough!
That’s why we really like ISO.
As far as how to set the ISO, you’ll have to check your camera manual since they’re all a little different. Just look up “ISO” in your index or table of contents.
One more thing… in normal picture-taking situations, most cameras are set to “automatic ISO” where the camera will vary the ISO between 50 and 300, depending on the lighting situation. Many photographers feel that it’s a good practice to turn OFF the automatic setting, and for normal picture-taking, set the ISO to as LOW a number as you can, just to get the least amount of noise.
For example, if you are outdoors on a sunlit day, you can set the ISO down to 50 and still have enough light for a good picture, but also get the least amount of noise.
That’s it for now. If you have you own experiences with ISO or flash or anything else having to do with your camera, we’d love to have you leave a comment, just below.
Happy Picture Taking!