Introduction
What exactly is a RAW file? Why is it often called a digital negative? On this page, we'll analyze the technical characteristics of this format and understand why it is always recommended for your digital photographs. Aren't you curious?
Colors in Digital Photography
Every time we take a digital photograph, the light reaches the sensor, stimulating millions of small receptors called photodiodes. Each photodiode converts light into an electrical charge proportional to its intensity, thus generating a black-and-white image.
The number of photodiodes in a sensor is huge, so to better understand the concept, we have created an example image in an intentionally low resolution, which you can see below.
The problem is that the sensor is in black and white, so it would be impossible to determine the colors of the scene, but a brilliant solution has been found: the Bayer grid. It is an array of red, green, and blue filters positioned in front of the photodiodes. You can see an example below.
We have understood that the light reaching the sensor is not the same as we perceive, but it's filtered through the Bayer grid, resulting in something similar to what you can see beneath.
Since the sensor can't see the colors but only the amount of light that reaches it, what the camera records is similar to the image below, with the only difference being a much higher resolution.
To obtain a color image, the camera's processor reconstructs the missing components of each pixel using the values of the surrounding pixels. This interpolation process is called demosaicing.
Let's try to keep things easy, avoiding explaining algorithms, CFA, light frequency, and non-standard sensors. So consider only that for one red and one blue pixel, there are two greens. This is because green is the tonality where our eyes perceive more details and contrast. On top of that, it's the channel where the luminance appears cleaner from noise.
The raw data recorded by the sensor also gives the name to the file format. What happens next with these raw data is that they get processed by the CPU of the device, which will:
- Read the signal from the photodiodes.
- Convert the analog signal into digital.
- Apply demosaicing to obtain the RGB values of each pixel.
- Apply white balance and color profiles as in the settings.
- May apply a denoising.
- May enhance contrast and sharpness via software.
- May apply optical corrections for the lens distortion.
- Compress the photograph and converted in the chosen format, usually JPG or a variant of HEIC.
After completing all these steps, the image will be saved on your device, ready to be viewed, edited, or shared. These operations are performed by any digital camera, whether you use a smartphone, a compact camera, or a DSLR.
What are RAW files?
So what exactly is a RAW file? It's an uncompressed file, preserving all the data captured by the sensor. In practice, it allows you to access the information from each individual photodiode, data that would inevitably be lost during compression.
To be even more precise, the RAW format preserves the sensor data with a depth of at least 1‑bit, monochromatic. Today, the standard in mid-range and high-end professional cameras is 14‑bit. The amount of tonal information that can be stored in 14 bits is enormously greater than in any compressed format. These values increase exponentially.
This greater amount of information provides a number of advantages, including a wider dynamic range, full control over white balance, and a higher color depth in the sense of greater tonal resolution. To be more specific:
- White balance and colors are fully adjustable in post-production.
- You can recover more than 4 stops of exposure, especially in dark areas.
- You work with an uncompressed 14‑bit file with a greater signal depth.
- Most of the in-camera presets can be adjusted afterwards.
- Overall, you have much more control over the final result.
- You can create an HDR image from a single shot thanks to the wider color space.
- In case of copyright disputes, owning the RAW file is indisputable proof of authorship.
Of course, not everything that glitters is gold. There are also some disadvantages to consider when shooting in RAW:
- The photographs will appear neutral and low-contrast, requiring post-processing.
- Before sharing or printing the images, you must convert them to a standard format.
- The files are much larger, both on the memory card and on your computer's storage.
- Dedicated software is required to process them, and you also need a decent computer.
In short, if you are photographing an event and need an image ready to print or publish immediately, you have to set up the camera properly and shoot in JPG. In any other case, you should proudly say, "I shoot RAW!"
To fully appreciate the real advantages of this format, you need to have a clear understanding of the concept of white balance. If you'd like to learn more about this important topic, we've written a dedicated page; you can find it below.
It's worth adding that if you've decided to take up this hobby, investing time and money in a serious camera, you should feel almost morally obliged to use it to its full potential, using the advantages of RAW files. You'll never go back.
Raw with smartphones and the DNG format
We need to talk about the elephant in the room, at least from one photographer to another: mobile RAW files. For many, it's almost a sacrilege.
Explained in detail, it would be an extremely technical and probably boring topic; we'll try to face it more lightheartedly, hoping you'll appreciate it, even if it inevitably leads to a bit of oversimplification.
Photography with smartphones has nothing to do with standard photography with DSLRs. Such small lenses and sensors would generate terrible images, unacceptable with modern standards. The RAW image generated by the sensor would be almost useless, being so low quality. The manufacturers came up with a smart solution; let's see what they invented.
When a phone takes a picture, it doesn't take a photo, but it makes a way more complex task: it takes even more than ten images in very rapid succession, then combines and blends them. It may use different exposures, take bits from one frame, bits from another, and even parts that are the sum of all of them. In short, there's a crazy amount of post-production work behind every shot.
Once the image has been cleaned up using the earlier advanced techniques, the phone adjusts gamma, contrast, and brightness through what's known as tone mapping, applies aggressive sharpening filters, and tweaks colors both scientifically and emotionally. It ends by compressing and saving the file as a JPG or, more likely, as a variant of HEIC, a standard format widely used on smartphones.
When we speak of smartphones, a RAW file isn't a "true RAW." It's an intermediate file between the previous stages: the phone performs all the advanced processing needed to produce an acceptable image but skips any "emotional" or "stylistic" filters. It's also saved in a lossless format with a higher bit depth.
The main advantage of using RAW on a smartphone is getting a less processed file: you still benefit from all the AI-powered optimizations applied during the first elaboration, but you also have higher bit depth in both color and luminance, avoiding the often exaggerated tweaks at contrast, color, and sharpening added by the manufacturer.
The downsides are the same as with traditional RAW files: they need some post-processing; otherwise they tend to look a bit flat. On top of that, RAW shooting will counter the immediacy and lightheartedness typical of smartphone photography.
The standard format in this field is Adobe's DNG, which supports bit‑depths up to 16‑bit, giving you plenty of freedom when recovering shadows or highlights.
Concluding, consider that only some mid-range and high-end camera phones allow RAW shooting, and while there are a few excellent mobile apps, the post-processing phase is still recommended to be done on a computer.
Demonstrating Ownership of a Photo
A RAW file is not a processed image; it's a container of data coming directly from the camera's sensor. Considering this, it's an absolutely incontrovertible way to prove ownership of a file in case of copyright-related disputes.
A professional photographer, when hired for a photoshoot, could often deliver to the client both the edited images and the corresponding RAW files. This way, its client receives full control and availability of the shots.
Out of curiosity, if it's not possible to provide the original RAW file, the presumption of evidence generally states that the person in possession of the highest-resolution version of the image is, logically, the actual owner of the photograph. Alternatively, also the EXIF data can be used.
If you want to share your photos without giving up ownership, we strongly recommend resizing them to a lower resolution. If the EXIF data are not needed, also remove them using a dedicated tool.
Raw Processing in Practice
Since it's a raw file, in the sense of unprocessed, you need a specific program to process a RAW. We recommend using a computer. You may choose to buy software or prefer a free solution. It's not in line with our philosophy to advertise paid products even though they are often highly professional and higher-quality solutions.
Each manufacturer provides its own software, which can be used to process the RAW files for free; this is the solution we actually use:
- Canon uses the extension .cr2 for its RAW files. Since we use Canon, we have written a tutorial for Digital Photo Professional, also known as DPP, in our old blog.
- Nikon uses the extension .nef for its files, and the program you need is Nikon Capture.
- Sony uses different formats, which have changed during the years: .arw, .sr2, or .sfr, and its program is called Sony Imaging Edge.
There are, however, dozens of alternatives that allow you to edit RAW files, with varying levels of quality and performance. Among all the free programs, we feel confident recommending Darktable, an outstanding open-source software for RAW processing.
It's an extremely complete and advanced program, capable of acting both as a photo library manager and a processor.
Let's do a basic workflow together so you can better understand what it means to process a RAW file. If you want more in-depth information, their website offers an extremely comprehensive manual, which you can read by clicking here.
The starting photograph is a shot taken during a hike to Cianderou, shown below in its RAW version, without any type of post-production correction applied. It's not a bad photo at all, but the sky is too bright, and the photo feels like it's missing some character. Even though the sky may look blown out, the RAW file actually contains information stored at a higher bit depth. Those details aren't visible on screen, but they're still in the file and can be recovered.
The first step is to adjust the exposure: let's darken the brighter areasand brighten the shadows so as to achieve the maximum possible dynamic range. Be careful not to clip shadows or highlights. It lacks a bit of contrast, but don't worry. You could also use more aggressive settings; we just prefer not to overdo it, as we like our photos to look more natural.
Next we choose to slightly increase the contrast and sharpness for a more impactful and sharp image. Be careful not to overdo it, as you may blow out the highlights and crush the shadows.
The final step is color balancing, with fine adjustments to the white balance and saturation. This ensures a photograph with accurate and vibrant colors.
This complete freedom in the processing phase has earned the RAW format the nickname "digital negative," since all you need is a moderately powerful computer to access a range of customizations that, in the film era, could only be done in the darkroom using potentially harmful chemicals and equipment that was expensive and difficult to handle.
Conclusion
We hope you liked this page about what RAW files are and why they are superior to JPGs. Before saying goodbye, we would suggest you read all the articles we wrote about photographic technique.
If you want to thank us, you can read the page Support Us. If you only want to suggest a change, propose something, or just say hello, in the section Contacts and Info, you'll find all the ways to reach us.