The RAW format is a type of files in which your camera stores the information provided by the sensor as it came right out of it, without any post-processing. JPG files, on the other hand, contain a heavily processed version of that original information so, in a way, they are the result of passing your original images through an automated post-processing workflow.
It is quite common to find people saying that you should always shoot RAW and, to be honest, you should always shoot RAW. That is probably one of the most useful advices you can get so I will not try to disprove it.
In fact, what I want to do in this post is show, in a practical way, the reasons why this is such a good advice.
For this, I will use the following photo of Atlanta’s skyline at night and apply some basic adjustments in Photoshop both to the RAW file and the JPG file so you can see the different results you can get.
Now I will compare the result of applying different filters to both files. However, this comparison is one that needs to be considered with care, since the JPG file has undergone a lot of post-processing in the camera already before opening it in Photoshop.
This processing helps produce somewhat smoother results sometimes, but this smoother result can be reproduced with further processing of the RAW file as we will see.
The first change was to apply a sharpening filter to both files in Photoshop. For this example, I used the ‘Smart Sharpen’ option available in Photoshop, with an amount of 100% and a radius of 3.5 px with the option to remove ‘Gaussian Blur’ selected.
The image below shows a 100% crop showing the result of applying this filter to the JPG file (left) and the RAW file (right).
The values selected (100% and 3.5) are too large for usual post-processing, but they help illustrate the noise issue that arises with sharpening filters. When comparing both images, there are a couple of interesting features. While the RAW file produces much sharper results (notice, for instance, how clear the letters on the top of the building are compared to those on the JPG image), the noise seems to be larger, especially on the flat areas like the sky and the walls of the building.
However, on the one hand, the noise is quite uniform, which makes it easier to get rid of, and on the other hand, since the result is a sharper image overall, the amount and radius of the sharpening filter can be decreased while still getting a similar result to that of the JPG file, allowing to further reduce the noise.
The next adjustment was to increase the contrast to 100% in both images using a Brightness/Contrast adjustment layer. The results are shown in the image below (once again, JPG on the left and RAW on the right).
The result here is remarkably better for the case of the RAW file. Not only is the whole image much sharper (the sharpening filter was removed before adjusting the contrast), but also the noise level is lower (notice the artifacts that appear on the sky on the left, a consequence of the JPG compression algorithm) and the color information is better preserved, for instance on the trees.
In this case, however, the fact that the JPG file has already been processed produces a darker image, meaning that the contrast adjustment could be less drastic meaning that the color information would not be completely lost.
A point where the RAW format has great advantage over a JPG file is when changing the exposure of an image during post-processing. When the camera converts the image captured by the sensor to JPG, a compression algorithm is used that results in the loss of valuable information in regions where the surrounding colors are similar. This has a noticeable effect in the dark areas as it can be seen in our following example.
In this case, I created an ‘Exposure’ adjustment layer and increased the exposure to +2.0. The results are shown in the following image.
If you look at the black board above the white truck, you can see that the pixels on the right image (RAW file) still contain individual color information while on the left image (JPG file) the color information is cluttered.
While both images are noisy, and one could even say from a simple visual inspection that the JPG is less noisy (and this is certainly true, since it has been already processed), the RAW image still contains all the original color information, so a simple adjustment in the contrast will even out the differences caused by the noise produced by the sensor. In contrast, the color information of the pixels from the JPG file are simply lost and cannot be recovered.
The lack of information in dark areas on JPG files has especially important consequences when processing dark images, sometimes making it just impossible to get any valuable information from them.
And that is, in few words, the importance of sticking to RAW format. Nowadays, processing RAW files is a very straightforward process, so there is no reason to let your camera decide what information it saves and what it discards and, believe me, even if you are still not convinced, one day you will be and, if you saved the RAW files of your favorite images, you will be able to go back and re-process them.
About the Author
Leonardo Regoli is a self-taught amateur photographer currently based in Göttingen, Germany. His main interests are travel and landscape photography; he currently works as a freelance photographer as well as collaborating with content for Sleeklens.