Adjust Your ISO - Better Photos... Now!

If you're shooting handheld in a low light situation and need more light, there are three things that you can do to get a proper exposure. First, drop your shutter speed as low as possible while still getting sharp photos. Second, open your aperture to let in more light. Finally, boost your ISO!

Raising the ISO on your camera makes the sensor more sensitive to light. Most cameras start at either ISO 100 or ISO 200 as their default. By increasing the ISO to 400, 800, 1600 and beyond, you increase your camera's ability to take photos in low-light conditions. This comes at a cost, though, as you'll also introduce more noise into your photos.



How high can you take your ISO? It depends on your camera. Each new generation of cameras provides superior low-light, high ISO performance when compared to previous generations. As technology improves, sensors become better at providing low noise, high ISO photos. The size of the sensor also makes a huge difference. A full-frame camera, which has a larger sensor (and larger pixels) than a cropped-sensor DSLR, can generally provide cleaner high ISO photos. You should experiment with your camera to see how high you can take your ISO so that, when the time comes to raise your ISO, you're ready!

Sometimes, instead of raising your ISO to make your sensor more sensitive to light, you might want to decrease your ISO to make your sensor less sensitive to light. For example, if you're shooting in conditions where you want a shallower depth of field, you'll want to use a large aperture, but doing this might overexpose your photos. Traditionally, you might reach for an ND (neutral density) filter to cut the amount of light coming into your lens. Now, you can drop your ISO and typically get another stop of exposure.

You might also want to raise your ISO when photographing a subject or event that moves quickly, such as sports. If you're getting a proper exposure, but your subjects are blurred because your shutter speed is too slow, by boosting the ISO you're able to raise your shutter speed, giving you the ability to freeze the action as it unfolds in front of you.

Back in the days of film, each roll of film had it's own ISO (or ASA) rating. This meant that once you started a roll of film, you could only change your shutter speed and aperture. The ISO was fixed until you changed rolls of film. Digital has opened up this third option and made it possible to capture photographs that were never before possible. By becoming comfortable with adjusting your ISO, you'll be much better equipped to get the shot when lighting conditions are poor.

Here are a few examples from when the lighting conditions were very poor.  There was hardly any light in this room.  I had been shooting with a flash, but I decided I'd try to shoot a few ambient light photos.  Even with flash, I had been shooting at ISO 1600.  Here's what it looked like at ISO 1600 with no flash:

f/1.8, 1/30 sec, ISO1600

When you look closer, you can see the
noise appearing.

f/1.8, 1/30 sec, ISO3200

Definitely more noise here.

Fortunately, with a few adjustments, you can still get a usable photo:

f/1.8, 1/30 sec, ISO3200

Read all of my DSLR tips here.