An 8-bit video camera outputs pictures where the RGB values are quantized to one of 256 levels. A 10-bit camera quantizes to one of 1024 levels. Considering that because there are three color channels, an 8-bit camera can represent any of 16,777,216 discrete colors. But can your eyes tell the difference?
The human eye can recognize about 10 million colors. So what is the benefit of a billion different colors if we can’t see it. Here’s a little primer on data in video.
Bit depth is the number of basic red, green and blue colors that can be stored in a frame of video. Each channel can display a variety of shades of the appropriate color. The number of shades determines the bit depth of the image.
The majority of video displays show images with an 8-bit depth, whether these are desktop monitors, laptop screens or mobile device screens. There are far more expensive and rare 10-bit monitors, but few of them are available to most eyes. Today, most 10-bit color in the TV market are when looking at 4K UHD TVs, while 1080p HDTV is 8-bits.
So, if our eyes can’t see 10-bit images and most displays can’t show it, why have all that 10-bit data? For display purposes, there is no reason at all. The value comes in processing the 10-bit data. With an 8-bit image, try stretching the saturation or contrast. You may fine you don’t have enough data and blank bars in the histogram are formed. With the extra 10-bit data, expanding the range will not cause gaps.
This is why it’s important to shoot precise video with today’s 8-bit DSLRs. Heavy post-processing will not be needed if the video is done well in the camera. But when that processing is needed, 10-bits is what you want to have when seeking beautiful processed video.
So working with 8-bit video is not bad unless you plan to do a vast amount of color or contrast changes. Most of DSLR video is 8-bits per channel and you have to make your picture as good as possible in-camera, otherwise post-processing may lower the quality of your final product.
The 4, 6 and 8K future is something else. As cameras get better and better and home receivers are further refined, expect to see more 10-bit video. It’s not about what we can see on a direct display, but for more flexibility in post-production.