Here's my attempt at some basics.
I've been shooting u/w video for fun since 2002. For reference, I currently shoot a Sony 1CMOS camera in an Amphibico housing.
My dive buddy just bought a Canon consumer HD camera and their housing.
I'm not a Mac person so can't help with that except that Final Cut Pro seems to get a lot of mention.
A couple other web options are the Videography forum on Scubaboard (I'm a regular participant/moderator there). The "what camera/housing should I buy" gets answered there fairly regularly. Underwatervideography.com shows promise.
There's also a couple of DVD"s, and several books. Most have dated gear descriptions but still provide useful basics.
The basics are similar for shooting stills or video. You need on-camera adjustments, enough light and optimally the ability to White Balance. Compensating for loss of Red at depth is also done with lights or an add-on filter.
There's about 3 tiers of "prosumer" housings available. (people hate that word..lol) The majority of u/w videographers likely shoot Sony cameras - at least just about everyone I know does except my b-i-l and his decision was based almost solely on cost.
The most recent are the Flip Mino HD, the JVC Picsio, Kodak Z18 and several other models including the GoPro Hero and other "helmet" cams. Most have fixed focus or other limitations but can turn out surprisingly good results. There are many u/w examples on Youtube or Vimeo.
Ikelite makes an affordable housing for the Flip, Picsio and Kodak, the complete camera and housing pkg. is under $500 - adding their video light/tray is about $300 more. There's also a housing for the GoPro and one other (Contour?) - I don't follow them.
The next step up is housing a "conventional" video camcorder. Canon sells 3 models that fit into their proprietary housing - camera and housing are each in the $450-800 range. My buddy has the HF200 in their WPV1 housing, it's a full 1920x1080 AVCHD (Hi-Def) camcorder but the housing has limited controls - on/off, start/stop, zoom/wide angle and one more I can't recall. It's also depth limited to 130' The front port is threaded so you can add a w/a lens or filters as needed - the camera has a built-in u/w mode but we had very mixed results with it in daylight this spring in Turks/Caicos. He plans to buy lights and a red filter now.
It does allow you to view the camcorder LCD screen in the open position. The current models are the MF30/300/31 and the housing is the WP-V2. All are on the Canon website. Differences in the cameras are primarily the storage media afaik.
A step up are dedicated Poly housings made by Ikelite, Equinox, Ocean Images and several others. These will range from a base price of about $800 to over $1500. Since the Ikelite/Equinox use mechanical controls, they're pretty model specific.
So paired with a Canon/Sony model they would still fall within your $2000 budget. Add on Ports, WA lenses, LCD Monitors and other options are also available. The Ikelite and Equinox are mechanical control models - a pushrod or button manually accesses each control function. With the Ocean Images and certain Sony (only) models, most of the controls are electronic on the handles.
With the Ikelite and O/I a manual control rod is positioned so that you can touch the LCD screen for White Balance and other control functions, the Equinox doesn't provide that option.
Some of the Ikelite models allow you to view the LCD directly - others use a mirror as the LCD is reversed and flattened against the camera - these pan backwards with Canon models - some of the Sony models have reversing circuitry included. The O/I models allow you to view the LCD monitor flat in the housing, Equinox provides a back mounted optional monitor - or has a restricted view.
A cost/feature reduced version of the Light & Motion Stingray is manufactured for TopDawg. Controls are on the housing, not the handles, feature differences and depth limitiations. It also has a flat port - which is actually good for macro. It also accepts a wide variety of Sony cameras.
Aquatica makes a video housing also. It's a mechanical model specifically made for three Sony camera models. IIRC it's $2250.
The three premier housing manufacturers are Gates, Amphibico and Light & Motion.
Amphibico just announced a cost reduced version of their Dive Buddy EVO - the housing I own - for $1500. The trade-off is that it has a flat glass front port and only works with certain Sony models. Light & Motion lists the base model of their Stingray housing at $1999 so depending on how much you can stretch your budget...afaik all the Gates line start about there also - I haven't looked lately.
And then there's lights - that can be $500-3500. And there's some pretty expensive pieces of glass out there for some housings with interchangeable ports. Other options are micro/hydrophones, flip down filters, external monitors, etc.
Links (had them all bookmarked):
http://underwatervideobasics.com/dvb/index.html
http://www.diveintoyourimagination.com/ - the Camera Coach DVD - the author Annie Crawley edits on Mac systems.
http://www.hammerheadpress.com/Book_Pages/...gitalvideo.html
http://www.usa.canon.com/cusa/consumer/pro...waterproof_case
http://www.ikelite.com
http://www.equinoxhousings.com
http://www.oceanimagesinc.com
http://www.topdawgvideo.com/
http://www.gateshousings.com
http://www.amphibico.com/rec/
http://www.uwimaging.com/systems/stingray
http://www.aquatica.ca/subpages/catalog/ho...ousings_dv.html
For other options - I maintain a video housing manufacturer list - it contains all that I'm currently aware of worldwide.
I would suggest also contacting a dealer or two for recommendations. Here are some I've met/dealt with.
My dealer is Mike Luzansky at H2OPhotopros - he's on here also (Mike L) http://www.h2ophotopros.com
Ryan at Reef Photo is my buddy's light dealer http://www.reefphoto.com
Backscatter sells video gear http://www.backscatter.com - Berkeley or Mitch?.
Joe Holley at MarineVisions owns underwatervideography.com http://www.marinevisions.com