If you're a keen amateur photographer, then you probably shoot your images in JPG format. In this short article we'll tell you why you should shoot in RAW format.
When you took your new shiny toy out of the box, it was more than likely set up to shoot JPG images. These are compressed images that store on the camera's card as a smaller file size than what they open up to in your photo editing software. But any professional photographer will tell you that these really are a compromise.
Shooting in JPG.
When you shoot in JPG, you push the button and your camera records an image with its CCD or CMOS chip and then the camera's firmware then "processes" the image and records a "finished" image onto your camera's memory card.
Shooting in RAW.
When you shoot in RAW format, you push the button and the camera records an image with its CCD or CMOS chip and then then writes the image to your camera's memory card, unprocessed, straight from the chip
So what is the difference?
Well, let's go straight to how you would process this in your editing program and the answer will become obvious as we go along. Say you download your camera card to your computer with a JPG image, and you notice that it is underexposed. Using Photoshop for example, you open up the histogram and it shows not enough exposure in the right hand side of the graph. You can "fix" this problem by dragging the histogram to the right, or simply by using Auto Levels. If you do this, you will see that the histogram now has "stripes" in it. These "stripes" are missing picture information. Anytime you change exposure, colour balance or contrast you are removing more picture information. Once you have gone down this path you are making it very hard to produce a quality image. Simply put, you have degraded the image.
Let's do it again in RAW.
Say you download your camera card to your computer with a RAW image (E.g. NEF which is Nikon's raw file format) and you notice that it is underexposed. What happens next depends on what photo editing software you are using. We'll start with Photoshop.
1. In Photoshop, when you open a RAW file you will get a pop up box that will open and you will be able to use one of the sliders to adjust exposure, colour balance, colour temperature etc and then the image proper will open with your changes in place. If you check the histogram, you will see that it is intact and you have a perfect image. Now when you close the file, Photoshop writes a small file into the same directory as your image. This file carries instructions on how you adjusted the image and next time you open it, these instructions will be applied. At any time you can change your adjustments. Because the original file always closes without changes, this is called "non destructive" image editing.
2. In Aperture when you open a RAW file you will get a pop up box that will open and you will be able to use one of the sliders to adjust exposure, colour balance, colour temperature etc and then the image proper will open with your changes in place. One fabulous feature of Aperture is its ability out show burnt out hi-lights and blocked up shadow areas. It does this by applying an orange over colour to burnt out areas and blue to blocked up shadows. By using the "Recovery" button you can usually recover the hi-lights and sort out the shadows with the "Black Point" control. Unlike Photoshop, Aperture then saves a new "Version" of the image. E.g. If you have image_001 you will then have image_001 Version 1 saved in the same directory. Again the original image is not changed, so again we have "non destructive" image editing. Once you have a great "Version", Aperture lets you export this image as a JPG, TIFF or small Email sized JPG to another directory.
Either way using RAW files will give you usually a much better outcome in terms of really high quality finished images. Using RAW can give you a tolerance of up to 3 F Stops in exposure latitude. (Although you should still aim to get exposure correct when you shoot!) You also get a fabulous latitude in areas of colour balance and in setting vibrancy.
Most high end compact digital cameras (e.g. Canon G9) and most DLRs (digital single lens reflex) cameras can shoot either JPG or RAW. Some can shoot both RAW and JPG and record them to either one or two cards in the camera.
Next time you pick up your digital camera, try shooting RAW and see the difference in your finished post processed images.
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