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Understanding shooting in RAW
Techniques
24 October 2007 09:32
Owning a digital SLR and never shooting RAW files is like never taking the camera off its auto settings. When you start shooting RAW you can control the entire image-creation process, instead of allowing the camera to make many of those processing decisions for you and presenting you with a JPEG.
RAW is the name given to a whole group of image file formats (including CRW, CR2 and NEF) which are produced by digital cameras. Unlike more familiar image formats, such as JPEG and TIFF, RAW files don’t contain the finished image ready for viewing. Instead they contain all the unprocessed raw data, read directly from the camera’s image sensor.
To translate this raw data you need RAW file conversion software, which opens up lots of new creative options.
Advantages:
• Correctly processed RAW images are sharper, more detailed, and contain more accurate colours.
• RAW files are recorded in a higher bit depth, commonly 12-bit or 14-bit, rather than the usual 8-bit. This extra information can hold brighter highlights and darker shadow details, and the tonality is smoother.
• The RAW data is hardly touched by the camera’s image processors before it is saved to the memory card, which allows your computer to perform a lot of the camera’s usual corrections post-capture. So if you don’t get the white balance, contrast or sharpness settings right when you take a shot, you can correct this on the PC. Even poor exposures can be sorted, to a point.
• Using a decent RAW converter package , you have a massive amount of control, from contrast adjustments with curves through to noise smoothing. Also, some adjustments, such as sharpening, are often far more sophisticated than the methods employed by your camera so the pictures look even better.
• Enhancing RAW files using RAW converter software is much easier than the equivalent enhancement to a JPEG using Photoshop or Elements. In just a couple of minutes you can completely overhaul an image to give it much more impact. The corrections are easier too: most adjustments can be made by dragging a few simple sliders.
Drawbacks:
• JPEGs are compatible with most software packages and are strictly standardised. RAW files aren’t as accessible, because every camera model produces its own RAW file to a different specification. You’ll have to install a compatible RAW converter on your computer to view and enhance the RAW images.
• A RAW image generally needs to be converted into a standard TIFF or JPEG before you can do much else with it. This potentially adds an extra step to your digital workflow and could hold up an urgent shoot or professional assignment. (Although if you do need to make any corrections to your images, you’ll save hours with RAW files as those enhancements are quicker to make.)
• Saved RAW file sizes are enormous. They’re roughly three to four times larger then the equivalent JPEG, so less images will fit on a memory card. However, CompactFlash and SD memory cards are becoming cheaper and cheaper, so a couple of 1GB cards will cure this problem for most people.
• These large files take longer to write to the memory card, which means that you’ll rely heavily on your camera’s buffer. This is used to temporarily store new shots as others are being saved. However, the buffer is limited and can easily fill up when taking loads of pictures in quick succession as you would when shooting sports and wildlife. If it does fill up, you’ll have to wait a few moments before you can take another shot.
