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You’ve seen it on the spec sheets for cameras you considered purchasing, you’ve read about it on one photography blog after another, and you’ve heard your photographer friends talk about it — shooting raw. But do you know what it is? What implications it has for your images and whether you should be doing it?
Raw is simply an uncompressed (or losslessly compressed) digital image file format; it’s often referred to as a digital negative because raw files themselves aren't typically used as finished images but contain all the data necessary for creating a polished, final image. This stands in contrast to jpeg (.jpg) format, which is a compressed, more or less finalized image file that has been stripped of a certain amount of information. Furthermore, while jpeg is an acronym so designated in honor of its creators (the Joint Expert Photographic Group), raw is not an acronym despite the fact that we often see it misrepresented as such — it’s just “raw,” not RAW.
Now that you have at least an abstract understanding of what raw format is, let’s take a look at why you should consider shooting raw.
The 12-/14-bit Advantage – The 8-bit jpeg format can contain a maximum of 16 million colors (256 shades each of red, green, and blue). Not bad, I suppose. But 12-bit raw files can reproduce 68 billion colors and 14-bit raw files are capable of a staggering 4.3 trillion colors. Beyond color reproduction, bit depth also has important implications for shadow and detail recovery; while the benefits of 14-bit files in comparison to 12-bit files seem rather modest for correctly exposed images, the greater bit depth plays a much more significant role when it comes to correcting extremely underexposed images.
Take Full Advantage of Dynamic Range – Raw files record and retain all the information captured by the sensor; this takes maximum advantage of any given camera’s dynamic range capabilities — the ability to accurately record the subtle transitions between the lightest and darkest parts of a scene. This translates into properly exposed highlights and shadows that don’t lose detail.
Get Clean Images – Since raw files are lossless/uncompressed files, they don’t exhibit any of the jpeg-related compression artifacts that can really distract from the aesthetic quality of an image.
Metadata Goes Along for the Ride – Producing a raw file means that all the metadata (camera settings) for a specific shot are included with the file but are not permanently affixed as is the case with jpegs. While it’s definitely good practice to get exposure correct in-camera, shooting raw means that you will have the option to adjust exposure (and other settings) later in post processing software.
Correct Lens Imperfections – Things like chromatic aberration and barrel distortion are definitely unwanted characteristics of any photo, but are factors you have to be aware of since no lens is perfect and will likely impart some degree of distortion upon your image. Unless your camera corrects for this internally, a jpeg file will carry whatever imperfections are present when the image is recorded. A raw file, however, allows you to fix or minimize these problems.
Potential for Better Detail – The sharpening and noise reduction processes available in image editing software is far superior to what’s done in-camera when jpegs are recorded. Working with a raw file in an external image editor will give you precise control over your image — you can achieve sharp, noise-free photos without sacrificing much in the way of overall image quality.
Non-Destructive Editing – Anything you do to a raw file (adjust exposure or white balance, increase contrast, correct lens aberrations, etc.) leaves the original data intact and, instead, essentially creates a set of instructions for how the image should look when saved in a different format. This way you never have worry about ruining a file; if you make changes that you’re unhappy with, simply start over with the original image.
The upside of working with raw files is obviously undeniable, but there are some potential “cons” that should be addressed as well.
File Size – Raw files are significantly bigger than jpegs — sometimes 2 to 3 times bigger. This means you will be able to fit fewer files on your memory cards and hard drives. But storage devices are becoming ever cheaper, so having larger, higher quality files isn’t really a deal breaker.
Also related to the larger file size, shooting raw will cause your camera’s buffer to fill up faster. It doesn’t affect burst speed itself, but when the buffer fills up you will have to wait for the camera to write to the memory card.
No Standardization – Every camera manufacturer has their own protocols for how raw files are handled; Canon software can’t read Nikon raw files and Nikon software can’t read Canon raw files. These proprietary formats can, however, be converted to the open source DNG (Digital Negative) format, making your files (hopefully) future-proof and universally accessible.
The Need for Processing – Raw files aren’t processed in-camera; you will typically want to adjust things like contrast, saturation, and sharpness and then convert the raw file into a more “viewable” format such as jpeg. All this will add more time to your workflow.
The negatives — if you can call them that — of shooting raw are mightily outweighed by the positives. Of course, there are those who may need to shoot jpegs or prefer to shoot jpegs in certain scenarios, and that’s perfectly fine. You do whatever works best for you. But if you’re concerned with getting the very best quality out of your images and having the freedom and flexibility to revisit and change those images at a later date, then shooting raw is the way to go.