Just made an article about underwater photography im going to put on PL soon, have a read and let me know if you think anything is missing or shouldn't be there....
http://www.projectlocal.co.nz/index.php/underwater-photography

if you want ill add a link to the sods photography forum.
cheers

I've only skim-read half of it but I'd make the changes below (in red).
Who would have thought I'd be offering spelling/grammatical advice... Can't comment on the technical content...

Starting out (a semi-colon, hyphen or something) what to do?
The best advice is take heaps of photos underwater of everything to practice focus, composition and general use of your underwater camera and all it's functions. Look at underwater photos you like and figure what you like about them (composition, color colour or angle) and try to mimic those things you like in your photos. Also shooting to the conditions is good for example if the visibility is only 5 meters then shooting macro is a good option.

SLR or point and shoot?
If your serious about underwater photography an SLR is the way to go. However it's never that simple (a comma, semi-colon, hyphen or something) below are advantages of both.[/b]

Oh and I personally would make the change below:

Buying a camera?
There's so many makes and models out there that it can be a bit confusing as to which camera to buy. One important thing to remember is not to get hung up on the amount (use number instead of amount) of megapixels as this is a lot less important than other things.

Who says I'm anal???

haha cheers it'll get sent to the proof reader once ive finished the article.

You talk about F stops but I think it needs more explaining what a F stop is and compare the difference between af1.4 and f22.

Also what dictates a wide angle vs telephoto.

I'd disagree here PH. To go into f stops properly would take another few thousand words. A basic explanation would take a hundred. The content is good enough-perhaps a link to a more tech minded piece would be usefull for those wanting to know.

Same with the wide and tele. You could just say wide is like looking at something with your eyes, tele is looking through a telescope.

Good piece though Andy. Some links to basic photography would be way easier than trying to re-write stuff that has been done very well everywhere.

The article states to get a camera with a low f stop. But it does not say what a low f stop is. Is 5 a low f stop? Is 10?

Its the same with wide angle. What is a wide angle? how is it measured? Is it 20mm? 35mm? 200mm?

f stops, or Aperture settings are slightly confusing at first. The lower the number the 'faster' the lens and the bigger the Aperture. IE; f/1.4 is capable of taking pic's in very low light levels, with fast shutter speeds but the depth of field(whats depth of field ) is very small. At f/1.4 the aperture is fully open-the hole which the light passes through is almost the same size as the glass on the front of the lens. These lenses are expensive. At f/22 the hole is very small, meaning you would need long exposure times and high lighting levels but the depth of field is large. Then you have to take into account another issue. At low f/stop settings the subject in focus will be very sharp and that which is not in focus will be blurry. Whereas with high f/stop settings most of the image will be in focus but the image will not be as crisp and sharp. Get it?

Wide Angle is from 10mm(very wide)-30mm(not very wide) this is where you can see a huge area in your viewfinder-typically a wide angle lens is used for landscapes. As you get a big area in your frame. Telephoto's start from(arguably) 70mm and go up to 1000mm. These are like looking through a telescope-so rather than having to walk right up to your subject you can, in reason, take a shot of something that is quite far away.
This is as basic an explanation as i can do.

Thanks Martin those are both great explanations. Although I wasnt looking for an explanation for my self, rather just an expansion of Andy article to explain what a good sized lens for a UW camera would be.

For example my Canon G10 has a 28mm- 140mm lens with f stop of 2.8-8.0

28mm seems as small as a P&S will go, there maybe something smaller but most are larger. eg G9 was 35mm-210mm. Thats better as far as telephoto goes but not as good for wide angle shots that would be used more under water.

A genuine question;

Are the figures for the lenses that you are talking about quoted in 35mm camera equivalent, because you often see a figure of, for example 5mm-15mm, but then followed by a 35mm equivalent conversion which is always much higher?

Many P & S cams have a smaller sensor than a 35mm film, or digi, cam. Up untill recently they even had a different type of sensor. Depending on what P&S cam it is, what make and what age it is will depend on what the actuall range the camera is.
I'm talking about 35mm DSLR's or SLR's. Although it gets a bit confusing with FX format Nikons as the sensor isn't the same size as a 35mm full frame(film). Hence if you bolted on a 70-200mm lens to my FX Nikon it's actually X 1.5. So the 200mm end becomes 300mm. Unless the lens is a designated FX lens and then it does what it says on the lens, so to speak.

So when i put my 1.7 times teleconvertor and my 70-200mm on my Nikon i get an actuall focal length of 510mm. Which is nice

Yes, its mostly quoted as 35mm equivalent. though not always stated as such.

For example my G10 has a 6.1-30.5mm lens (28-140mm 35mm equivalent).

As Martin points out there are many sizes of sensors out there now so its hard to compare 2 different sized lenses in from of 2 different sensors unless they are compared to an industry standard. E.G 35mm film.