At one time or another, you’ll probably hear people talk about “noise” in digital photos. Nope, this doesn’t involve screaming kids, it actually involves tiny specks of random color that show up in an image. It’s basically the digital equivalent of film grain.
Noisy photo (no it doesn’t look noisy from here, but look at the close-up below):
Close-up (note the grainy look)
How do you avoid it? Shoot with film (kidding). Here are a few suggestions:
Shoot at the lowest possible ISO - Your ISO setting controls how sensitive your CCD or CMOS sensor is to light (digital film speed). The higher the number, the more sensitive it is and the less light you need to get a photo.
However, the higher you set your ISO, the more noise you pick up. So, always shoot with the lowest setting possible. If your camera has an “auto ISO” feature, use it – this will keep the ISO as low as possible. As the light gets brighter or darker, it adjusts your ISO automatically.
Shoot at higher shutter speeds - If you stick your camera on a tripod and try some long exposures, you’ll probably notice a nasty increase in noise – especially if you’re shooting at a higher ISO.
If you need to take long exposures, you should probably experiment with different ISO / shutter speed combinations to see what you can get away with. You don’t want the noise to get out of control and get all wild on ya.
Digital Zoom - Here’s yet another reason why not to use your digital zoom – it can add extra “noise” to your photos. Since a digital zoom is forced to create pixels where none exist, it can’t help but add to the noise problem.
Heat - Yup, believe it or not, if the sensor in your camera is hot this can also add noise to the photo. In practice, I’ve not really seen that much of a difference, but it may be a good idea to keep your camera at room temperature. You know, like off the dashboard of your car and with you instead
Inexpensive Sensor - I don’t mean to hurt anyone’s feelings here, but the higher quality the sensor in your camera, the less noise you’ll pick up in the photo. Not saying you need to run out and spend $4000 on a camera, just pointing out the facts. Generally speaking, the more bucks you lay down for the camera, the less noise you’ll put up with.
What if, despite doing everything you can, you (gasp) end up with some noise in the photo? Well, you can use your photo software to “despeckle” it!
Most imaging software includes either a noise reduction filter or a despeckle filter. Just run that filter and some of the noise should be eliminated (or maybe we should say, “turned down” :-). It’s not perfect my any stretch, and it does soften the image a bit. However, a little help is better than none at all…