Digital cameras don’t capture ready-made images. The data captured by the sensor has to be processed first. This happens automatically and instantaneously if you set the camera to shoot JPEG images. Many cameras don’t give you any other option. However, more advanced models like high end compact cameras, DSLRs and mirrorless cameras will also let you shoot RAW files.
RAW files are like undeveloped images
The advantage of RAW files is that you can do the processing yourself and perhaps get better results, or better control over the final picture, than you would get from JPEG images processed in-camera.
RAW files are digital data straight from the sensor. There is an analog/digital conversion before that to convert light values into digital data, but a RAW file isn’t even ‘demosaiced’. This means that the red, green and blue image data hasn’t even been converted into a full color image.
RAW files offer more flexibility
There are other differences. For example, when the camera processes a JPEG image it uses the white balance setting you chose on the camera to discard any unwanted color information – and you can’t get this back later. A RAW file, however, retains all the color information captured by the camera so that you can choose, and change, the white balance setting later.
You can think of RAW files as being like undeveloped film. Some say it’s like a digital ‘negative’. Indeed, Adobe has created its own DNG (Digital Negative) format for RAW files. But ‘undeveloped film’ is probably a better description because it’s like the days of film processing. Back then, you would choose different chemical developers to change the way your negatives would come out, whereas today you can choose different RAW processing tools to change the look of your RAW files in a similar way
How RAW processing works
Lots of different programs can process RAW files into editable images. Very often it’s built in so seamlessly that it’s not treated as a separate process, and you can open and edit a RAW file in just the same way as you would a JPEG image.
However, different RAW processing tools will produce different results, and some are better than others at reducing noise, recreating colors accurately, recovering bright highlights and dark shadow detail and so on.
Adobe Camera Raw and Lightroom
Perhaps the best known RAW processing tool is Adobe Camera Raw. This is included with Photoshop and works alongside it to process any RAW file you try to open within Photoshop. Once you’ve made your adjustments for the RAW processing, the image is then processed and opened in Photoshop.
Adobe Camera Raw is built into Adobe Lightroom. The adjustment tools are the same (though the interface is a little different), but this time the RAW processing is seamless, and the editing tools are the same as those used for JPEG images.
Other RAW processing tools
Other RAW processing software may give better results. Capture One has integrated RAW processing, just like Lightroom, and is very good at bringing out detail while suppressing noise. DxO PhotoLab is renowned for its RAW processing quality, especially with its new DeepPRIME process.
Things to keep in mind about RAW files
- The results you get from processing a RAW file yourself may be better than those you get from in-camera JPEGs, but not necessarily, and you may have to do some editing work to make the RAW files look as good. In-camera JPEG processing has been carefully tailored to match the camera and its sensor’s capabilities.
- You can’t ‘see’ a RAW file. You can only see a processed version created by the software you are using at the time.
- You can’t edit a RAW file. When you use Adobe Camera Raw, or Lightroom, or any other RAW processing tool, you store the processing adjustments you’ve made in the software itself as processing ‘metadata‘ or in a ‘sidecar’ file alongside your photo. The original RAW file is never altered.
- Changes you make in one RAW processing tool won’t appear in another. With the exception of Adobe Camera RAW and Lightroom, which can both ‘see’ each other’s adjustments, RAW processing software makes adjustment which are not visible to any other program. You have to ‘export’ a processed JPEG or TIFF image to make your changes visible to other programs and devices.