![]() This seems to be based on a spurious correlation between bit depth and dynamic range and a misunderstanding of how digital capture works. Some technical authors equate the bit depth of a camera’s RAW capture or processing pipeline with the range of tones – the dynamic range – that the sensor can capture, so that an increase of 1-bit in the capture system will yield an increase of 1EV in the dynamic range. There seems to be a lot of confusion around this. Even with this upsampling process, a 16-bit TIFF file will be a much better starting point for image manipulation than an 8-bit JPEG. RAW processing software produces 16-bit TIFF images by ‘upsampling’ the RAW file, whether it’s a 12-bit or a 14-bit file. This will be a much larger file, but far better for image editing. A better alternative is to produce a 16-bit TIFF image. You can create a JPEG from a RAW file, but then you’re back where you started. Some photo editing programs will let you work with RAW files directly, but with others, including Photoshop, Affinity Photo and various plug-ins, you will need to process the RAW file into an editable image first. A few medium format cameras can even capture 16-bit RAW files. ![]() More advanced cameras will capture 14-bit RAW files, which are better still. Now, even cheaper DSLRs and mirrorless cameras will capture 12-bit RAW files, which is enough to give a big step up in tonal subtlety and editing potential compared to JPEGs. This 2-bit advantage over JPEGs is still worth having, but is low by today’s standards. Some older cameras captured 10-bit RAW files. The contain the data captured by the sensor in an unprocessed state, so you do need to use RAW processing software to produce editable images. RAW files are captured at a much higher bit depth than JPEGs and therefore have much subtler tonal information. The only way round this is to capture images with a higher bit depth, as these are far less likely to show any tonal separation, even with heavy manipulation.Īnd the only way to do this is by shooting RAW files instead of JPEGs. This can show up as digital artefacts like ‘banding’ effects or ‘posterisation’, particularly in skies or other areas of even tone. These three RGB colour channels generally work in combination to produce a much subtler, wider range of tones.Įven so, if you edit a JPEG photo to shift the color balance or change the contrast, you can start to see these tones separating visually. ![]() This means that the three color channels used to make up the photo (red, green and blue) all use 8-bits of data – so sometimes these are also called 24-bit images (3 x 8-bit).Įach color channel in an 8-bit JPEG can record 256 different shades, and while that doesn’t sound like enough to give a smooth transition of tones, you should remember that tones in a picture are rarely composed of one channel alone. JPEG is an ‘ 8-bit’ format in that each color channel uses 8-bits of data to describe the tonal value of each pixel. This produces small, compressed files that don’t take up too much space, can be opened and displayed on any device and yet can still display the subtle tones needed for photographs. ![]() Most images are shot in the JPEG format for convenience. Here’s a table showing the number of different values for different bit depths: Bit depth This is especially relevant in photography, where you need to be able to render subtle differences in tone and color. The number of bits used is the ‘ bit depth’. But when you use them together the combinations are multiplied so you can record a much wider range of values. ![]() In computing, ‘bits’ are either on or off, so there are only two possible values. All digital data is made up of ‘bits’, and that includes digital images. ![]()
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