The Enthusiast's Guide to Multi-Shot Techniques

36. USE IMAGE STACKS IN PHOTOSHOP TO REDUCE NOISE

ONE OF THE best uses for image stacks is to remove the digital noise that appears in images when you use very high ISO settings or leave the shutter open for long periods of time. Digital noise appears as unwanted spots of color, especially in darker areas of constant color and tone. These spots of color are random, so if you shoot the same scene multiple times with the same settings, the noise will appear in different spots in each image. You can see an example of digital noise in Figure 36.1, which is the result of using a high ISO, in this case ISO 6400. In Figure 36.2 you can see the noise ...