Pixiq

One of the problems shooting at night or in low light situations with digital technology is noise. When we all shot film, grain — the digital equivalent — was an acceptable look with many types of pictures. In fact, in some cases, photographers used films specifically to get a grainy look. In the digital realm, though, no one likes noises.

There is a unique technique to eliminate noise completely. I think you will very much appreciate knowing about this.

The photo you see here of an otherwordly landscape in Namibia — a quiver tree forest — was taken a few days ago. I am leading a photo tour to this African country, and on this particular evening we had incredibly dramatic sunset lighting (the trees are only slightly enhanced in color from the original). I then combined the landscape with a shot of the night sky that I took the next evening at Sossusvlei where the largest sand dunes in the world are located. The sky was as crystal clear and stunning as I had ever seen it — it seemed like I could touch the Milky Way. The night shot required some careful planning, and when I captured what I wanted I then used Photoshop to get rid of the unwanted noise. Let me explain.

For the picture of the stars, I wanted a long exposure to accumulate the light so the sky looked even brighter than it does with our eyes. However, a long exposure would create star trails due to the rotation of the Earth. I didn't want that. Therefore, I limited the exposure time to 10 seconds. I used a 50mm f/1.4 lens to gather as much light as possible during the exposure, and then I raised the ISO to 1250. That's why the sky is as bright as it is in this image.

In order to eliminate the noise, the first step was to take 10 separate shots of the sky, obviously from a tripod, and all in RAW mode. I opened all the images in Photoshop as psd files, and then I used the command File > scripts > load files into stack. In the dialog box that opened, I checked the two boxes at the bottom and then browsed for the 10 exposures of the sky.

Finally, I used the pull-down menu command Layers > smart objects > stack mode > mean (available only in CS5 Extended). This combined the images in such a way that the noise was completely gone without softening the image as noise reduction programs always do. It was magic!

I then used the magic wand tool to select the original sunset sky behind the trees and pasted the stars into the background. To be honest, when I saw these two images together I was completely blown away.