MY PENSION POT TOOK A HAMMERING when I decided to buy a top-of-the-range DSLR camera that would take grain-free pictures at very high light-sensitivity settings.
I imagined that Id be using it to take natural-light pictures at depth.
It does do this, but the first thing I realised on using it is that natural light under water is always diffused and from above. When trying to take pictures that look interesting, I soon got bored with the sameness of that.
The other problem was that as soon as you get more than a few metres from the surface, the water absorbs all the light at the red end of the spectrum, and shots start to look very monochromatic.
You cant use a filter because you cant put back the colour of light that simply isnt there.
It can give a moody look, but doesnt bear too much repetition between pictures.
Despite what some people may tell you to the contrary, if you want colourful underwater pictures at any depth greater than a few metres, you need to take some white light with you.
By white, I mean a light source that emits a full spectrum of colour.
It would be nice if there existed an inexpensive lamp bright enough to illuminate still pictures. What you really need, whatever sort of camera you use, is an underwater flash.
Remember that the red part of the spectrum is absorbed after travelling only a short distance through water, and this explains why super-powerful flashes dont necessarily give a better performance over a longer distance.
This YS-01 flashgun from Sea & Sea is designed to work with almost any type of modern digital camera that has a built-in flash, and you can use it either as a digital slave or in fully manual mode.
It is very compact at 13cm along its longest side, and weighs only half a kilogram.

Electrical connections have always been susceptible to failure under water, so Sea & Sea has opted for a flexible fibre-optic connection between the YS-01 flash and camera, using the cameras on-board flash to trigger the other. Fibre-optics are impervious to flooding.
Its essential that the YS-01 fires at exactly the same time as the camera takes the picture, but because digital cameras have different ways of firing their on-board flashes, you need to select the setting thats right for your camera.
One setting ignores any pre-flash that the camera might make. Another allows a degree of through-the-lens exposure control. The third is a simple manual connection.
Thanks to the instant results possible with digital cameras, you can do this in the comfort of home, and simply need to remember which setting is right for you.
The fibre-optic connection is designed to plug directly into Sea & Sea DX compacts as well as Sea & Sea polycarbonate camera housings. Depending on the connection, you can also use the YS-01 with any other compact.
You may need to cut off the Sea & Sea elbow at one end and push the fibre-optic cable into another hole on your non-Sea & Sea cameras underwater housing, so that it can see your on-board flash when it fires.
The YS-01 flash has two synch sockets, so you can daisy-chain several units should you so wish.

Power Supply
The YS-01 is powered by four AA batteries enclosed in a floodable compartment. If you flood it, the batteries are ruined, but at least the rest of the flash should remain salvageable.
It takes slightly less than two seconds (with ni-mh batteries) to get ready for the next shot after the flash is fired.
The manufacturer claims around 230 flashes from a set of alkaline batteries, or a massive 330 if you install ni-mh rechargeables.
A pressure-relief valve takes care of any battery gases that might otherwise build up.

Light Output
If you choose to use it in manual mode, there are ten output settings from which to choose.
The even coverage of the light is 100°, but if you use it in conjunction with a lens of a wider angle-of-view, or have the lamp so close to the subject that the lowest output setting is still too bright, you can opt to fit the snap-on plastic diffuser supplied.
The colour of the light represents daylight on a day with bright sun and white clouds.

In the Water
I had no compact camera of my own to hand, so I used the YS-01 with my professional-quality digital single-lens-reflex. My own underwater camera housings have no provision for using the cameras on-board flash, so I used it as an additional flash, and fired it by the light of the other flash I had hard-wired to my camera.
The YS-01 mounted nicely on the mounting balls of my housing by means of the Sea & Sea jointed arm (at extra cost) and I was able to aim it exactly where I needed it.
Even at full power I found it effective only for close-up photography, but this is the style most often effective with a compact camera.
Of course, used in this way I gained no advantage from its advanced TTL features.
When I shot a sequence of more than, say, four pictures, I had to wait several seconds for the Sea & Sea YS-01 flash to recover and get ready for the next shot. Otherwise it seemed as quick to recycle as my regularly used flash.

The red ready-light turns to green to confirm that the flash has adjusted automatically when in TTL slave mode. This function is available with almost any camera that has a pre-flash mode.
There is also an LED targeting light that, once turned on, turns off the moment you take the picture, so it doesnt add an embarrassing light spot in the centre of the photograph.
It comes on as soon as the flash is ready to go again.
The YS-01 makes a viable alternative to other compact ancillary flashguns on the market, especially at the price, which puts it in a category of its own.

Inon 240Z, £650
Inon S2000, £439

PRICE £345. Mounting arm £200 extra, fibre-optic connection £56
GUIDE NO 100 (ISO100) in air
BEAM ANGLE 100° (110° with diffuser)
NUMBER OF FLASHES 230 (alkaline), 330 (ni-mh)
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%