There are different reasons digital noise shows up in our photographs and a big part of knowing how to eliminate it is by understanding how and why it’s there in the first place. As with most things, it’s best to correct high ISO in camera when possible and there’s a number of things you can do to greatly decrease the amount of noise using in camera techniques. (Of course, depending on the shooting conditions, we won’t always be able to avoid noise. Luckily, post production software is getting really good at taking care of what we can’t get in camera.)
What Is Noise?
There are different types of digital noise and if you’re the kind of person that likes to know all the details and science behind how things work, you could spend quite some time learning all the technical details of noise. But, for the sake of this particular article, we’re going to do our best to abridge the information into something a little more user and time friendly…So, think of image noise as static on a radio, it’s a distortion that can be so faint and subtle it’s hardly noticeable; or, it can be so overwhelming it’s unpleasant to listen too (or in this case look at). Digital noise is the equivalent of grain in film photography.
When working on a color image, noise will also appear more colorful, like this:
Common Causes & How To Fix Them
The Cause: Low Light, High ISO
One of the leading causes of digital grain is poor, insufficient lighting. As photographers, we can do several things to remedy low light, one of those things being cranking up the ISO on cameras. Shooting on a higher ISO does prove to be useful to achieve a proper exposure when shooting in low light, but the downside is the resulting noise.
The Fix: The higher ISO you shoot on, the more noise you are likely to get. That’s why you always hear the pros recommending you shoot on the lowest possible ISO while still getting a good exposure. You may need to bring in additional lighting, open your aperture wider, and/or slow down your shutter speed to do so. (Just keep in mind long exposures can also be a culprit!)
The Cause: Heat
If your camera’s sensor gets too heated, it can cause grain in the image your taking. A heated sensor could be caused by extended use of your camera–such as in long exposure photography–or by the temperature of the environment.
The Fix: If the heat is caused by long exposures, shorten your exposure time if possible. Do your best to avoid keeping your camera in direct sunlight on a hot, sunny day to help keep the camera’s internal temperature down.
The Cause: Sensor Size
Unfortunately, not all sensors were created equally. Some are more prone to digital noise than others. Full frame sensors, such as those found on models like the Canon 5D or Nikon D800 series, are larger and produce less noise. The sensors on crop sensor (APS-C) cameras like the Nikon D3200 or Canon Rebel line are smaller in size and are more prone to noise. It’s also worth noting that technology has immensely improved in the last few years and we’re seeing the smaller sensors produce very good quality images even in low light situations, so don’t be too quick to blame noise on your camera.
Fixing Noise In Post Production
With every new release, noise reduction software is getting better and better. Even if you encounter some unavoidable noise, chances are you can correct a lot of the distortion in post. Some methods include adjusting settings like the luminance, detail, etc…You may also wish to make or purchase a pack of presets for consistency and automation of the process. There are programs and plugins that are designed specifically for this purpose. Stayed tuned and we’ll go into these options more in depth in an upcoming post!