You can find many articles online discussing the benefits of shooting in RAW and probably an equal number full of counter arguments stating that it is possible to obtain equally good results shooting in JPEG. Whilst that is definitely true, I want to discuss the reasons that pushed me to exclusively use RAW in the hope that it can persuade others to do the same. I liken RAW processing to taking the camera off ‘auto’ and shooting in ‘manual’ mode. When people are starting out in digital photography, it can seem like another area full of technical jargon that forms a barrier preventing its uptake. However, once you have an small understanding of the processes involved and how different settings can impact your results, you will find that letting your camera do the processing can be the limiting factor in achieving your photographic vision.
What is RAW?
A RAW file is an uncompressed image file that records the data from the sensor ‘as is’, with minimal processing. Depending on your camera, this file will most likely contain either 12-bit or 14-bit data. When shooting in JPEG, the camera will take the RAW file, process it with a number of generic actions (typically contrast/saturation adjustments, correcting for white balance and sharpening) before compressing the image down to an 8-bit JPEG file. That difference in ‘bit depth’ is the key here. The 12-bit image will contain 2^12=4096 tones per channel. Given that there are three channels per pixel (red, green and blue), that equates to 4096x4096x4096= 69 billion possible tones per pixel….
Now those numbers are almost too large to comprehend, however it is quite simple to consider in context. When you take a JPEG file from your camera into Photoshop to process, there are only 256 possible tones to define the colour for each red, green or blue channel, which means that when you start apply changes to contrast or brightness, there are a very limited number of possible tones for each pixel, which can result in obvious image degradation if pushed too far. With a RAW image, the number of possible tones is that much greater that more significant changes to can be made without any impact on the final image quality. This doesn’t come without a cost though. Due to the increased bit depth of RAW files, they are anywhere from 2-6 times larger than the corresponding JPEG when recorded in camera. This will make your vast memory card seem very limited. Additionally, where as a JPEG is typically printer-ready straight out of the camera, a RAW file will need to be manually processed in your digital darkroom. So, to answer the obvious question of ‘is it worth it?’, lets consider the benefits…
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