Saturday, July 11, 2009

How to control digital noise

We first mentioned about digital noise a couple of weeks ago in this blog.

We were discussing ISO, and how the higher the number the more the noise in digital images.

And the longer the exposure, the more the sensor heats up. It is this heat that is responsible for most of the noise in digital photography.

Most of the time the heat issue is out of the photographer's control - especially in the warmer months.

All digital cameras produce noise - even the high end ones, especially at higher ISO settings.

So what is a photographer to do?

Once again, technology comes to the rescue, this time in the processing of the image on the computer instead of in the camera itself.

There are programs and plug-ins for programs that work with your photo processing software that can help remove this blasted noise that plagues us photographers.

Some of them let you isolate certain areas, and some of them will handle the entire image.

The one I use is Noise Ninja, a photoshop plug-in, and I would be so lost without it.

I evaluate my image several times during the processing of it so I can track the noise level each time I do something.

One reason I do this - processing the image too much can also add noise.

Sharpening is notorious for adding noise, both in the camera and in the computer processing too.

So, the less you manipulate the image, the less the noise.

But suppose there is noise that needs to be removed.

These programs work their magic, but as you know, if something seems too good to be true, it usually is.

Using too much noise removal will leave you with lost details and soft edges. Image quality can suffer when it is used too heavily.

Once again, a light hand and sometimes just using it in areas that are prone to noise - skies, shadows, and some textures, will yield great results.

It is all just a matter of experimenting and learning what works.

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