and what is RAW? (i am new at this)
Thanks for any help.
RAW pertains to how images are generated in the camera. As you no doubt know, light hits the camera's sensor, and is converted into digital information by the sensor. This digital information is then processed to generate the image that you finally get from the camera.
Most point and shoot cameras produce images in only one format - jpg (or JPEG). To generate the jpg image file, software inside the camera carries out a number of processes, including:
- demosiacing (the sensor in your camera is only able to determine the level of light hitting each sensor site. To achieve a colour image, a filter pattern is used so that only a particular colour (usually one of red, green or blue) hits an individual sensor site. Thus each sensor site has neighbouring sites that measure different colours. As a result, when combining the data from all the sensors of each colour, there is a need to fill in the image information for the 'holes' in the image data that result from neighbouring sensors not being the same colour. This interlopation is called demosiaicing.)
- White balancing. The information captured by the sensor is not affected by the white balance setting in your camera, but the setting is used when the camera creates the jpg image.
- Colrimetric interpretation, Gamma correction. These pertain to achieving an image with natural and 'correct' looking colours.
- Noise reduction, anti-aliasing, and sharpening. These are processes to improve the appearance of detail in the image, especially with 'edges' or boundaries between one thing and another in an image.
- compression. jpegs are compressed image files. What this means is that the image data is compressed by various means (i.e. propellerhead mathematics!) to allow the same image to be represented using less memory. Furthermore, the compression is 'lossy'. With jpg compression some of the image data is actually 'thrown away' and cannot be recovered by any post-process. The compression is such that (for most people) the quality of the image is not significantly degraded by the compression process i.e. for the most part the information discarded is not 'visible' in the image anyway. Compression is the reason why a jpg image from a 7Mpx camera is usually less than half the 7Mb in file size that might have been expected.
What this means is that when shooting in jpg, your camera is making quite a few decisions for you about how your image will look.
Cameras that offer a RAW mode essentially allow you disable all of this processing. Instead, the data from the sensor is stored as it comes off the sensor, with no manipulation. The first impact this has is that the file size will be bigger. A 7Mpx camera will produce RAW files of approx. 7Mb. The second impact this has is that you will need to use software on your computer to do the processing that the camera did in order to produce jpgs (or other image file formats) that can be shared, because the RAW data cannot be read as an image by most image displaying software. There are a variety of tools used to process RAW files. A popular one is the Adobe Camera RAW plug in for their Photoshop product. These RAW processors allow you to control the processing of your RAW data to your own specification, so instead of the camera making decisions about how your image will look, you do. The downside to this, is that you spend alot more time post-processing your images, but some people specifically enjoy this as much as the taking of the photo in the first place.
This is all somewhat academic for you, however, because I am pretty sure that the A570 does not have a RAW mode, so the image data is never available in RAW format from your camera. There may be a hack you can download from the internet, and by placing it on your SD card, the camera software is modified to allow you to use a RAW mode. Obviously, this is outside of the warranty, so its very much use at your own risk!
Hope that helps.
