To further elaborate on Nickb's excellent post:
You basically have 2 quality settings. RAW and JPEG. Under these are sub settings like "sRAW" but that is unimportant for our purposes here.
When you take a picture in JPEG, the camera looks at the exposure based on aperture, shutter speed, and ISO. It then edits the photo for you. The camera decides which white balance is best (or uses what you selected before the shot). Honestly who has time or accuracy to select a perfect "K rating" every time before the shutter is pressed? Especially concerning actinics, I have neither. It likely adds a little noise reduction which blurs the image. It sharpens the image, and edits the image in a few other ways as well. Basically you are trusting the camera to be your Photoshop.
When you take a picture in RAW, the camera takes the exposure and stops. It saves every combination of white balance possible, so that you can try them all and see what really looks best later. This is the main aspect for your actinic shooting. Actinics, by nature, are very blue. Your camera likely won't recognize it as too blue, it just assumes your a Florida Gator fan. With RAW you can turn the image red (counter balancing the blue) without sacrificing any image quality from the comfort and patience of your computer *after the fact*. You still get the cool effects on the corals because of fluorescence. You're just making the image red enough to make the sand white and the rock grey and the non-florescent organisms the color they should be.
Basicaly JPEG edits everything for you...aka Auto Mode.
RAW edits the image in every way possible so to speak, and lets you call the shots. After you edit your RAW image to perfection, you then save it as a JPEG.
JPEG images are MUCH smaller than RAW images, simply because instead of saving ALL the data...the camera decides in 1/1000 of a second what to throw away and what to keep for you. So if are sure you can get it right every time with JPEG...more power to you. This is like Jesus asking whoever has no sin to throw the first stone.
RAW images are very large, many of my images are over 20MB each. With a 4 gig card I still average about 350 shots per card though which has to be quite a few rolls of film. Ask any professional photographer and I will bet money you will hear, "Considering how cheap memory cards are in this day and age, there is no excuse not to shoot RAW."
Just like with reefkeeping, the better I get at it, the more I understand how everything works, and the more complicated/sophisticated the equipment on my wishlist gets...
