Should you be shooting RAW?

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.  If we compare that to the other bit depths, you will see the difference:

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…

The benefits of RAW

As mentioned above, when shooting JPEG, the camera processes the image internally, before compressing it to a lower bit depth.  The processing applied by the camera is generic, and uniform across the entire image.  In contrast, when you capture RAW images, you have full control over how much processing is applied to an image, and where in that image you apply it.

Given the increased bit depth of the RAW files, any image you capture is much more forgiving than the corresponding JPEG would be.  For example, if you didn’t nail your exposure, and you over-exposed the sky of a landscape photograph, leaving it nearly white, you will be able to recover much more tonal data in the RAW file and potentially save what, otherwise, may be an image destined for the recycle bin.  Similarly for shadow data, much more information is retained meaning under-exposed regions of an image can be recovered to show detail that would otherwise have been lost.

On the left is the image presented straight out of camera. Exposing to contain the bright sky caused the trees to be under-exposed, and appear and a dense block of dark colour. The image on the right shows the same image processed to boost the shadows to reveal detail that may otherwise have been lost

Similarly, one image can contain enough tonal detail to create an HDR-style image from one file.  The exposure of the image can be increased/decreased during post processing to give 3 images, as if bracketed, and can be combined to give that effect of increased dynamic range, but all from just one image.

When shooting in RAW, you no longer need to set your white balance in camera.  The increased bit depth of RAW files means that the white balance can be defined, by precise colour temperature (in Kelvin), during post processing rather than by a limited number of defined presets in camera before the shutter is pressed.  Due to the increased bit depth, significant white balance shifts do not have a negative impact on the final image quality.  No longer do you fire off a few frames before remembering that you left the white balance on ‘incandescent’ even though you are now outdoors.

The top image shows Bruges, captured at night, straight out of camera. The white balance of the bottom image has been processed to reduce the colour temperature in order to give a more realistic representation for the colour of the stone buildings, without any impact on the image quality.

Sharpening can be applied as much as you want and even where you want, without over-sharpening a pre-sharpened JPEG image.  This can be used to emphasise details in one section of an image, or just generally give you control over the final image output.

This image on the left shows a cheetah that has undergone some sharpening to increase detail. The image on the right is the mask applied to the sharpening effect. Imagine that black and white image superimposed over the top of the cheetah; the area of white represents the portion of the image to which the sharpening effect has been applied and the area of black represents the portion of the image to which the sharpening effect is not applied. Therefore, in this instance, the sharpening has been applied only to the eyes/nose of the big cat, to further emphasise the sharp focus in this area, and increase the impact of the close portrait.

The added bonus

As if the above points weren’t enough, what has to be one of my favourite reasons for shooting in RAW is that all image editing is non-destructive.  Unlike a JPEG file, where any changes made to the image are permanent, all changes made to a RAW image are stored in a metadata file associated with the RAW file, leaving the original file untouched.  This means you can never irreparably ruin an image by saving some mistaken changes and also you can go back to an image a few weeks, months or years later and reprocess it, from the original RAW, as your processing skills improve.

Now, I would be lying if I said there was not a learning curve associated with RAW processing.  You will need dedicated RAW processing software to manipulate your images, but typically cameras that support shooting in RAW should ship with the manufacturers own software for doing so.  There are also a large number of alternative free programs out there, as well as software packages from well know image editing giants, such as Adobe.  With a little bit of research, you will see how easy it is to squeeze the most out of your images, and you will soon wonder why you weren’t shooting in RAW sooner.

Given that most cameras should give the option of shooting in ‘RAW+JPEG’, where the camera records both the RAW file and processed JPEG file to the memory card, you haven’t got an excuse to not give it a go the next time you are out with your camera.