Thursday, February 25, 2010

Wednesday Word of the day! JPEG vs. RAW

Ok, a day late, I know, but I hope you will forgive me.

Since we talked a little about the different coloration you can do to photos last week, let's talk about image compression this week. As long as you haven't been living under a rock for the last couple of years you have probably heard of JPG or GIFs.

JPEGS - Joint Photographic Experts Group. This is the name of the committee that designed the standard image compression algorithm. JPEG was designed for compressing full color or grey scale digital images of natural scenes. It doesn't work so well with non-realistic images, such as cartoons however. JPEG does not handle the compression of black and white (1 bit-per-pixel) images or moving pictures.

The other choice often used is GIF. A graphic file format mainly used for Web graphic or small animated (GIF) files. Not good for photographs as it only contains a maximum of 256 colours.

Most cameras output directly to JPEG or RAW format. RAW files store the unprocessed image data at 12 bits per channel. Directly from the camera's imaging chip to its memory storage device. RAW image files must be processed with special software before they can be viewed or printed. These are normally in the form of a plug in for Photoshop or as a standalone product. . The advantage is that you have the ability to alter the white balance, exposure value, colour values, contrast, brightness and sharpness as you see fit before you convert this data into the standard JPEG or TIFF format. Professional digital photographers import RAW image data directly into photo-editing programs like Photoshop CS (which comes with a Camera Raw plug-in that works with most popular RAW formats.)

If you are serious about your photography, I would suggest shooting in RAW, it gives you so much more freedom and flexibility. Yes, it takes up more hard drive space, but hard drives are cheap! Especially when that perfect shot is just slightly off and you need to tweak something. RAW will save you most every time.

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