Image noise is externally important in my business, as a professional fashion photographer my images have to be on point, expressive, and noise free. As most fashion shows are at night and most shoots are indoors, I have to adjust the light accordingly. There is a lot of light available during an indoor shoot; but free shooting during an event, especially during the night time is tricky to perfect. Which is why photographers require a lot of practice to produce noise free images every time. I have years of practice that allows me to produce noise free images, and today, we will talk about image noise, its types, causes, and a possible solution.
Both luminance noise and color noise are visible in the shadows, and dark areas, rather than bright areas. This is because bright digital images are produced using a strong signal.
Image noise in digital photography describes the visual distortion, that looks like grains, or splotches of discoloration in some images. Image noise is worst when you are shooting in a low light situation. There are times when you are only able to see noise when you enlarge an image.
There are two main types of image noise:
- Color Noise
- Luminance Noise
Color noise is considered to be more objectionable from these two, as it offers an unnatural look. On the other hand, Luminance noise is more like film grain. Images with color noise show blotches, there might be one, or many; but they simply ruin the image and its worth.
Both luminance noise and color noise are visible in the shadows, and dark areas, rather than bright areas. This is because bright digital images are produced using a strong signal. The amount of color and luminance noise vary from camera to camera. However, most Digicams produce images with higher noise when compared to a DSLR, because they house a smaller image sensor.
Almost every camera in the market today includes a noise reduction processor, especially when the exposure is longer than one second, and when you are using a higher IOS setting. Most DSLR’s feature a separate noise reduction for long exposure and high IOS adjustment settings. Which means you might be able to turn them on/off depending on your camera. This simple feature allows photographers to strengthen noise reduction.
If you see tiny white dots scattered all around your images, keep in mind that this is a type of pattern noise. Any image you capture under the same conditions will feature these pattern noise. It is highly common in long exposure shots, especially when you set the ambient temperature at high.
There is a process called “dark-frame subtraction”, that allows you to remove most pattern noise from images. In this case your camera saves two different images in one click. One is taken with the shutter open, to capture the picture; and another one with the shutter closed to help record noise. The camera then subtracts the noise automatically, and leaves you with an image that is noise free. The total image processing time is doubled, but you are left with a noise free image in most cases.