Digital images are comprised of little bits of information called pixels. The number of the pixels is part of the image resolution. Bit depth is another part of the image resolution. For instance, a six-megapixel (MP) camera would capture six million pixels in an image. The bit depth would deal with the color and shades of each particular pixel. The more shades and colors a pixel can have will mean better quality in the subtler shades of an image.
Digital Camera RAW Image Data
Digital cameras capture data in RGB format and about 12 bits in each channel. (red, green and blue). The average amateur photographer sets their camera to save the image in 8-bit JPEG format. With 12 bits there are more colors and shades in each level than there are in 8 bits. Therefore, by saving images in 8-bit JPEG format, a great deal of image information is thrown away. Much of this information is in the highlights and shadows. This results in blown out whites and murky blocked up blacks. Not to mention, some of the subtler color ranges are lost altogether.
What is RAW Format Exactly?
In a nutshell, shooting in RAW is saving all the information captured by the camera sensor. When the camera is set to save as a JPEG, internal processing occurs and image information is thrown away. By saving the image in RAW format, all the picture information captured by the sensor is saved.
Advantages of RAW Images
- All image information is saved.
- Highlights and shadows have more detail.
- More color detail.
- Greater bit depth, which means more color information to work with.
- Non-destructive image files. RAW files are opened and adjusted with RAW conversion software. Edits are overlaid as an extra file and the original image is not changed. The photographer can revert back to the original image at any time without image information destroyed.
- The camera does not neutralize colorcasts. The camera does not process sensitive color information, such as sunset hues, tones and subtle color changes.
Disadvantages of RAW Images
- Larger file size.
- A RAW editor is necessary to open the images. (Photoshop, Capture One or many others are available on the market)
- Download and write times are longer because of the bigger file size. This means capturing fast action sports shots in burst will be a problem and more time will be needed to download the images to a computer.
- RAW files need to be edited. JPEGS and TIFFS can be used without edits if the color was white balanced before shooting.
- Targeted editing is not available in most RAW editors. (The excepting is CS4)
Summary
Saving images in RAW format gives the photographer all the image information and allows greater room for digital imaging and processing. More details and subtle colors are saved in the image information giving images greater depth and quality. The trade off is mostly in time spent processing the image and less versatility in shooting fast-moving action shots. For quality and detail in digital images, the pros choose RAW format.
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