If you have spent any time hanging out with photographers, you may have heard the term “shooting RAW”. And if you have mentioned the fact that you that you don’t know what it is, you have probably been met with wide eyed disbelief, followed by a sympathetic “you don’t know about shooting RAW?”. Well that’s about to change. This guide will help you understand what this RAW stuff is and how it can help you with your photography.
RAW vs JPEG in a nutshell
When you take a photo with your camera the image that is captured by the sensor is read and compressed in order to save the amount of information that will need to be stored.
JPEG compression results in a low level of dynamic range and a loss of sharpness to the image. A lot of camera specific metadata is also lost. This is regarded has heavy compression.
A RAW file is able to store almost of the dynamic range that the sensor picks up and there is very little loss of sharpeness. When a RAW image is captured compression still takes place but to a much lesser degree. All of the camera specific metadata is also kept.
Dynamic range explained
When we observe a scene through our eyes it is often much different to what we see on camera. If you have ever photographed a sunset you will probably have noticed that it is impossible to correctly expose the sky as well as everything else. With our eyes we are able to see the details in both the sky and the darker ground. But with the camera we only manage one or other. This is because our eyes have extremely wide dynamic range and our cameras don’t… Or seem not to.
When you shoot an image light from that scene passes through your lens and hits the sensor. Depending on the quality of the sensor more or less of this light is successfully converted into a digital signal. High quality sensors will obtain more digital information which results in more dynamic range being captured.
However, all of this information would take up a very large amount of space and take a long time to process. Therefore the software on the camera has to convert this into a compressed version of the file. This is where the decision to go JPEG or RAW really matters.
The clipping issue
With a JPEG the dynamic range is lost because the camera will apply a preset to the RAW data. This kicks out a file that narrows down the dynamic range to something that is much smaller to store. This causes information to be clipped. Once the dynamic range is gone, it is gone. No amount of brightening will bring back details in shadows and no darkening will fix blown out highlights. What you see is what you get.
However, with a RAW file almost all of this dynamic range is gathered and stored. This means that even though an image may look too dark on your computer screen, there will be “hidden” information in the pixels. These can bring back details that would otherwise be lost.
A simple way to think of JPEGs is to imagine that a pixel stores a brightness value of between 0 and 1. Whereas, a RAW file will be able to store values either side of that as well.
Why JPEGs lose sharpness?
Dynamic range is not the only thing that is lost when compressing images. Sharpness can suffer greatly. The JPEG algorithm is designed to find patterns and colour similarities in the pixels of an image. If pixels share an almost identical colour then they are effectively merged. You can read in much more detail about JPEG compression algorithms elsewhere online. The important thing to understand is that with a JPEG you are not getting a pixel by pixel representation of what the camera sensor saw. Rather than that you are getting an approximation.
Many cameras will apply a sharpness filter to images as they are being read off the sensor. This is great for snapping those quick holiday snaps for social media. But when taken into an editing suite for cropping and further editing this can show itself and cause problems. In some cases very obvious “JPEG artefacts“ can appear when images contain intricate patterns, fine lines or small text.
With RAW files there is almost no image compression that will affect sharpness. The image is a pixel by pixel account for what the sensor saw. No sharpening is needed in camera. Sharpening can instead be done in the edit suite with much finer control.
How to shoot RAW
Not every camera is able to output RAW files. However, most consumer and all professional DSLRs, mirrorless and compact cameras can. Even action cameras such as GoPros and some mobile phones are able to create RAW images.
Most modern cameras will have an option in the settings menu to change the quality and format of the image. By selecting RAW or RAW + JPEG you will be able to produce RAW files. In some cameras you may have the option to change the level of RAW file compression. In most cases a compressed RAW file and Uncompressed RAW file will have very little difference. It is usually worth using compressed RAW files. This can save disk space and cut down the time it takes to write the file to the SD card.
Things to consider
Although the process of shooting RAW is very much the same as shooting JPEG it is worth understanding a few things.
- It is best practice to slightly underexpose images if the scene has strong highlights as it is always easier to recover details in the shadows than highlights.
- Getting the correct white balance is not so important. Full control of the white balance is available in the edit suite as all of the colour information is retained.
- There is no need to add or use image profiles in camera. These are pointless as the “image profile” will be created when you edit the image later on. A RAW file is likely to look flat and dark straight out of the camera – but all of the information is there to make it pop.
How to view and edit RAW images
Viewing and editing RAW images can seem confusing at first. You are probably used to just opening a JPEG up and viewing it in whatever application your computer comes with. RAW files are a little bit different as they can’t be read unless they are decoded by the right program. Each camera make and model will have its own RAW file format. So a Sony RAW file is completely different to a Canon or a Nikon.
Programs such as Photoshop and Lightroom come with additional software that reads RAW files. Depending on the version, these may already contain the right codecs and drivers to read RAW files from your camera. However, if they don’t you will either have to update them or download the files from your camera manufacturer’s website. A quick Google will give you the information that you need.
Here are some popular camera RAW codecs
Editing in Adobe Camera RAW
One of the most common pieces of software for editing RAW files is Adobe Camera RAW. This which ships with Lightroom and Photoshop. With this program changes can be made to many aspects of the a RAW image including: exposure, white balance, levels, RGB curves, clarity, sharpness, noise levels, saturation and much more. Many of these controls are similar to those found in Photoshop and Lightroom themselves. Gradient filters, radial filters and brushes can be used to refine certain areas of an image independently.
In the image below we can see a RAW file that has been brought into Adobe Camera RAW before any processing has taken place. The image looks flat and there is very little saturation. This is normal in a zeroed RAW file as all of the information is stored in the pixels but has not yet been processed properly. By looking at the histogram we can tell that there is no clipping of information.
After some processing the image looks a lot more dramatic and engaging. Using the exposure settings, some gradient filters and adding some saturation to specific hues the image now appears to have a lot more depth and contrast. The white balance in the sky has also been adjusted to cool it down slightly.
As you can see the use of a RAW file in this situation has meant that lots of detail has been brought out in the sky in a way that would not have been achievable with a JPEG.
JPEG vs RAW comparison table
|Large dynamic range||*|
|White balance editable||*|
|No loss of sharpness||*|
|All camera metadata stored||*|
|Small file size||*|
|Readable on most devices||*|