Canon EOS Rebel T3 Series: Choosing the Raw File Type
The Quality settings on the Canon Rebel T3 and T3i determine the file type, which simply refers to the type of image file that the camera produces. Your T3 or T3i offers two file types — JPEG and Raw (sometimes seen as raw or RAW), with a couple variations of each.
Each manufacturer has its own flavor of Raw files; Canon’s are CR2 files (or, on some older cameras, CRW). You’ll see that three-letter designation at the end of your picture filenames on your computer.
Raw is popular with advanced photographers, for two reasons:
Greater creative control: With JPEG, internal camera software tweaks your images, adjusting color, exposure, and sharpness as needed to produce the results that Canon believes its customers prefer (or according to settings you chose). With Raw, the camera simply records the original, unprocessed image data. The photographer then copies the image file to the computer and uses special software known as a raw converter to produce the actual image, making decisions about color, exposure, and so on, at that point.
Higher bit depth: Bit depth is a measure of how many distinct color values an image file can contain. JPEG files restrict you to 8 bits each for the red, blue, and green color components, or channels, that make up a digital image, for a total of 24 bits. That translates to roughly 16.7 million possible colors. On the EOS T3i/600D, a Raw file delivers a higher bit count, collecting 14 bits per channel.
Best picture quality: Because Raw doesn’t apply the destructive compression associated with JPEG, you don’t run the risk of the artifacting that can occur with JPEG.
But of course, as with most things in life, Raw isn’t without its disadvantages. To wit:
You can’t do much with your pictures until you process them in a Raw converter. You can't share them online, for example, or put them into a text document or multimedia presentation. You can print them immediately if you use the Canon-provided software, but most other photo programs require you to convert the Raw files to a standard format first. Ditto for retail photo printing.
Raw files are larger than comparable JPEGs. Unlike JPEGs, Raw doesn’t apply lossy compression to shrink files. This means that Raw files are significantly larger than JPEGs, so they take up more room on your memory card and on your computer’s hard drive or other picture-storage devices.
Whether the upside of Raw outweighs the down is a decision that you need to ponder based on your photographic needs, schedule, and computer-comfort level. If you decide to try Raw shooting, you can select from the following Quality options:
RAW: This setting produces a single Raw file at the maximum resolution (18 MP).
RAW+Large/Fine: This setting produces two files: the Raw file plus a JPEG file captured at the Large/Fine setting. The advantage is that you can share the JPEG online or get prints made immediately and then process your Raw files when you have time. The downside, of course, is that creating two files for every image eats up substantially more space on your memory card and your computer's hard drive.