also what is raw mode and does the 570 have it?
There are numerous threads in various places about so-called RAW image files. Here are two places to start reading
ONE and
TWO.
As for whether the A570is can shoot/record RAW format, the answer is emphatically YES! But, you have to download the software that allows you to do so from
HERE. The installation is very simple and convenient. It does not void your warranty because the software does not modify the firmware. It is placed on your memory card and is merely a program run (if you so choose) from the card when you turn the camera on.
I have been using the CHDK hack for about 6 mo and really, really, really like the RAW file product so much much more than what is saved as a JPG equivalent. One word of warning about the software: if you format your memory card to properly erase all the files and reclaim unused card space, you may delete the folder containing the CHDK software. I haven't tried a card format since I installed the CHDK software, so I don't know what will happen. Have a back-up installation in a folder on your computer or another card, just in case.
FYI, the CHDK software saves the RAW format (CRW is the Canon-specific format for the A570is) files and does not interfere with the normal JPG version of the same image. Thus, you get both JPG and CRW files. This allows eventual side-by-side comparison of identical images saved one way or the other. In my experience, the CRW file is better in about 95% of cases, and in about 90%, it is much better than the corresponding JPG.
Because the CRW files are much bigger than the corresponding JPG files, and because both are saved, you may need a larger memory card if you want to keep all your images on a single card during a trip. Depends on how many shots you take, of course. The best plan seems to be to calculate memory requirements based on your personal shooting rate per day, then buy the appropriate sized card, multiple cards or just bring your computer along and upload the files at a convenient time.
I use Picasa to view and preliminarily edit my files. Seems almost silly to use this program because it is not "high tech." However, it has a major benefit that I have not been able to find anywhere else, at least to this point. Picasa not only reads and displays CRW files, it does so with the proper white balance! This is unique, in my experience, having examined several editors and file viewers, including Photoshop, FastStone, DNG4PS-2, Gimp and a couple of others. Although white balance can usually be adjusted easily in these programs, the image is initially displayed without it, unlike the case in Picasa. Typically, a single click on "I'm feeling lucky" followed by a single sharpen is enough to obtain a nice image in Picasa. More sophisticated editing should be done with a more advanced program. However, with a file saved in the CRW format, that will mean first translating it into digital negative format ("DNG") using something like DNG4PS-2 (a free download), then using Photoshop to edit the image.
One of the PITA "features" of Picasa is that you cannot save a viewed/edited file in any format other than JPG. Therefore, if you want to actually work with RAW images in Photoshop, I suggest that the CRW image be converted to DNG format before any editing. Otherwise, you will be wasting your time because your Picasa edits do not affect the original CRW image. From Photoshop, of course, you can save the DNG in any number of fileformats, including TIF or JPG.
