ISO is one of the most important aspects of photography that anyone using a DSLR should learn about. Along with shutter speed and aperture, ISO is one of the three “Pillars of Photography”. To get the most out of your shooting, understanding how all three pillars work and how they affect each other is key.
What is ISO?
If you’ve worked in the world of film photography, you might know it as the film speed. Well, it hasn’t changed too much. In essence, the ISO is the measure of the sensor’s light sensitivity. You can adjust your ISO settings to determine how bright or how dark you want the exposure to be. The higher the ISO number, the brighter the image.
How Does it Work?
Here’s the catch: it comes at a price. The higher you increase your ISO, the noisier the image will be. Noise is that grainy look you’ve seen in photos.
Left: shot at ISO 200 / Right: shot at ISO 8000
(both shot on Canon 5D Mark III)
I wish I could tell you the perfect ISO range to shoot in if you would like to avoid noisy images. However, every camera is different. Generally, newer digital cameras can shoot at a higher ISO without looking as grainy as older cameras. The technology is getting there! Maybe in the future we’ll have a perfect world where you don’t have to give up any quality for shooting at a high ISO… fingers crossed! It’s important to play around with your DSLR camera and see at what point the ISO is high enough that the photos would become unusable. That way you’re not fiddling around last minute during a shoot.
Why would you want to shoot at a high ISO if you know that your images might turn out noisier? Sometimes you’re in a situation where you don’t have much of a choice. For example, if you’re shooting a concert in a dark venue, you will need to bump that ISO up! Don’t be scared of increasing the ISO, getting the shot is more important than missing out because you don’t want grainy photos. I learned this the hard way…
Being in control of ISO will help you be in more control of your photos. Instead of leaving the setting to automatic, now you can choose the level of noise in your images. The more in control you are of your settings, the more fun you can have changing the style of the shot. There are a couple of questions to yourself before choosing an ISO speed:
- What is the light like?
- Are you shooting in a situation that will require you to increase ISO?
- Do I want a noisy photo?
- Sometimes grain can add a certain artistic and film-like quality to your photo.
- Can I use a tripod?
- If you are shooting a scene like the night sky, often you can avoid having a high ISO speed. Since you have a tripod for stability, you can use a longer shutter speed.
- Is there going to be movement?
- Like the reference above, shooting the night sky with a long shutter speed is easy because the scene is stationary. Shooting with a long shutter speed at a concert or wedding reception will create a different look entirely. You have to decide if you want to capture movement or not by increasing the ISO and adjusting the shutter speed accordingly.
This was an outdoor concert, not an easy place to use flash. So the ISO had to be increased quite a bit (and shutter speed a little slower) to compensate for the lack of light. Oftentimes, ISO grain can be fixed in post-processing.
How Do I Change it on My DSLR?
As we all know, different cameras have different setting layouts. If you don’t know where to find the ISO settings on your digital camera, you should be able to find out easily by referencing your manual or user guide. Most companies keep their manuals online too, so it’s an easy Google search.
Left: Canon / Right: Nikon
Nikon: some Nikon bodies will have the ISO button on the top left
If you’re just starting out with digital photography, this might sound a little intimidating. Don’t worry! Just get out there and start shooting. Nothing beats hands-on learning. Words like ISO, aperture, and shutter speed will all start to make sense the more you understand your own digital camera.