(If you see any technical terms here you’re not already familiar with, check out our handy glossary of photographic terms).
At its most basic, RAW is a bigger file with more flexibility than a JPEG. The RAW file has more data (actual raw data, as the name infers), is more forgiving of creative and corrective adjustments, and is (literally) open to interpretation. JPEG is smaller, faster to work with and visually consistent, but inflexible and with very limited adjustability.
But let’s get into the weeds…
Here’s a technical explanation of what each format is. This discussion starts with the camera itself — specifically, the camera sensor.
Light coming from a light source (i.e. the sun) bounces off an object and through the camera lens, coming to focus on the digital sensor. In a brief moment of time, that light is recorded. However unlike film where an actual photochemical reaction happens and converts the film into something we can visually see (after processing, of course), in digital, it’s all data. Just ones and zeroes.
At the moment of exposure, the camera can do one of two things. It can either store that data (the “raw” data) into a RAW file, or it can convert that data into color pixels and save that in a JPEG file. (OK yes color pixels are also just data, but that’s beside the point. The colors have been decided).
When a camera converts the raw data to color information, it has to decide for every single pixel (with millions and millions of them in a single photo) what its color value should be. In an 8-bit JPEG file (which is a universal standard and has been for over 25 years), every single pixel has to be one of 16.78 million colors, made up of three primary colors — red, green and blue. There are 256 possible values for each color in an 8-bit color space. That’s 2 to the 8th power (2^8=256), then 256 cubed (for each of the three colors; 256^3 = 16.78 million).
That sounds like a lot, but it really isn’t. It’s actually quite limited. Let’s compare to the RAW file.
A RAW file, depending on the camera recording it, can be 10-bit, 12-bit, 14-bit, or potentially even higher. The difference between just 8-bit and 10-bit is mind boggling. While 8-bit is 16.78 million possible colors, 10-bit is over 1 billion colors. 12-bit is nearly 69 billion, and 14-bit is over four trillion!!! Yeah, that’s a lot. But it’s important to understand that you’re not actually storing that many colors — you’re storing the potential for that many colors. Let me explain.
The RAW file is, again, raw data — not color pixels. A RAW file stores every last bit of information that the sensor was able to record, and sets it aside for later processing. You, the photographer, then take that file into a program like DxO PhotoLab and that RAW file is decoded. Remember when I said that a RAW file was open to interpretation? Every program like DxO PhotoLab, or Adobe Photoshop, or Capture One each have their own algorithm to decode that RAW file, written by their engineers and tuned to a way that they collectively thought looked good. This is why if you open the same RAW photo in a bunch of different programs, each one will look different. Some will be more saturated than others. One might have more emphasis on the blues while another features richer reds. One might be brighter, with more details revealed in the shadows, and another may be darker, showing more details in the highlights. Since the engineers who wrote the software can’t look at every single photo every photographer takes and adjust the code to make that single image look its best, they write the software to decode the RAW file in a generally pleasing way — something that will make most photos look pretty good. Then they give you the tools to continue to enhance it so you can make it look the way you want it to look. This is why you want to shoot RAW — you get to decide what the image finally looks like.
Remember the JPEG, which the camera already decoded? The camera itself has decided what this image should look like, and permanently written that interpretation to a file. Yes you can adjust it a little bit, but not much. If you try to adjust the exposure too much, you’ll clip shadows and highlights. If you try to shift or saturate the colors too much, you’ll see them break apart and reveal banding and blocking. Why? A big part of this is because it’s only 8-bit and has very limited colors to begin with. But mainly it’s because you’re trying to change a decision that’s already been made, instead of making the decision for yourself.
For two reasons, in two steps. First, because the data exists. If you shoot JPEG, when the camera decides how to decode the RAW file, it throws away a LOT of information. Everything that was captured outside of a simple 8-bit sRGB color space is gone, tossed, lost forever. When you shoot RAW, that data still exists. But so what if you can’t see it, right? Because the second part is that you can pull it into range. You can recover those highlights and shadows and extremely saturated reds and other colors and values and data that exists, but can’t yet be seen. When you open a JPEG photo of a white wedding dress in the sun, and the details on that dress are missing, there’s nothing you can do about it. But when you open the RAW photo of that same dress, and the details on the dress are missing, you can simply drag the exposure or highlight recovery slider and pull that data back into range. It’s there — it’s just hiding. There are limits of course, and that has everything to do with your camera, but in general, you can always get data back from a RAW file that has already been discarded in a JPEG.
OK, so why would anyone ever shoot JPEG? Plenty of reasons! First, the files are considerably smaller. Your memory card may be able to hold hundreds of RAW files, but thousands of JPEGs. Because they are smaller, they clear the buffer and write to the card faster, so anyone shooting sports or other fast action will find that they can shoot more frames in a row if shooting JPEG before they have to stop shooting to let the camera catch up than they do when shooting RAW.
Also, all that RAW processing takes time and effort! Sure it’s relatively painless and fast, but you have to do it. When shooting JPEG, you don’t. You can literally drag the photos from the memory card into a website. (You wouldn’t… but you could).
Another reason is that you may like the look your camera assigns to the images! I know I do… I have tweaked my LUMIX cameras to deliver a “look” that I particularly like (and I often change it depending on what I’m shooting). That look is in the JPEG but not the RAW file because, again, it’s just raw data. If I can get a look that I like right out of camera, then why not shoot JPEG and avoid individually processing the images?
The obvious answer is that I’m throwing away all the RAW data. But now we enter the final option. You can shoot RAW. Or you can shoot JPEG. Or… you can shoot both.
Pretty much every digital camera will let you choose between RAW, JPEG, or RAW+JPEG. Shooting this way negates the first two advantages I listed — now my photos take up more space because there’s two of them, and they take longer to clear the buffer because there’s two of them, but it gives me the best of both worlds. I get to have my JPEG, and RAW file, too!