[SeanKP]

Hi guys

I posted some shots in the gallery from my recent trip to the Red Sea and Robski requested that I post to the forum explaining how they were taken so, here goes.

Obviously, the photos were taken whilst scuba diving. Reasonable results can be obtained whilst snorkelling but I find it much harder to get a decent composition from above than in amongst the action.

I used my 350D with a 28mm Sigma f1.8 in a special underwater housing made by a Belgian company. The housing allows you to control virtually all of the camera's functions whilst underwater. The front of the housing contains a port with a perspex front through which the lens points.

Housings for digital SLRs tend to be expensive (more costly than the camera) but there are housings for many of the point and shoot cameras out there at very reasonable prices.

As sunlight moves through water the light is filtered out so, obviously it gets darker the deeper you go. Additionally the various colours are filtered at different rates. Red is the first to be lost, then green and finally blue. This means that, with no additional help, pictures taken below a metre or so will look blueish.

Many (most?) underwater photographers use a strobe (a waterproof flashgun) to bring back the colours but I discovered shortly before the trip that mine wasn't working and so all of my shots were taken with available light. This meant that all my shots had a horrible blue hue to them. However all was not lost. I shoot in RAW format and am able to adjust the white balance of the picture afterwards using Photoshop. Using this technique I am able to fully restore colour to pictures taken at less than about 12 metres deep and I don't have to worry about backscatter which are unsightly white marks caused by the light from a strobe bouncing off particles in the water.

Fish tend to move a lot more slowly than birds (my other photographic obsession) and using the 28mm lens as opposed to a 500mm, camera shake is much less of an issue. Underwater though, it is even more important to get as close to your subject as possible. You need to minimise the amount of light-filtering, particulate-filled water between your camera and the subject as far as possible. This can be tricky as fish, like birds, tend to have a zone of comfort which they don't like being invaded, especially by bubble blowing, clumsy oafs that we divers must appear to be.

I have tended to shoot at ISO 200 on shutter priority with the speed set to 1/100 sec but am planning on experimenting with fully manual next chance I get.

Well, that's probably a lot more than you all needed or wanted to know and so I'll end it there but, if anyone has any questions, feel free to ask.

Sean