The stress of packing, check-in and travel is behind you. Late last night you arrived at the hotel and stumbled to your room through the dark and the fog of jet-lag. Now it's morning, and you’re excited to dive.
Except it isn’t glorious tropical sunshine that is beating down, but a torrential downpour that is drumming on the plastic sun-loungers.
You’ve come all this way to a classic wide-angle destination, famed for picturesque reef scenery and friendly marine life, and have been welcomed by far from ideal photographic conditions.
The good news is that bad weather rarely lasts long in the tropics. However, the aim of this month’s column is to encourage you to embrace those rainy days and to try some creative techniques that are actually easier under thick cloud.
The obvious option on a rainy day is to reach for the macro lens. And this is a sensible choice. But today I want to focus on shooting wide-angle in the rain.
First, it’s valuable to understand how heavy skies affect light under water. Obviously they make everything darker, but there is also a subtler effect, because thick cloud also causes light levels to fall off more rapidly with depth.
Under a high sun, with blue skies, light penetrates deeply under water. If we take a vertical wide-angle picture the camera will record a pleasing range of blue throughout the frame.
Heavy clouds don’t just lower light levels at the surface; they produce a faster fall off of light through the water column. Take a vertical wide-angle now, and the bottom of our frame will be almost black and the top almost white.
We don’t want such unattractive backgrounds in our pictures. Rule one for wide-angle under thick cloud is to be really careful with our blues.
We should compose so that the camera only sees a manageable range of blues in our compositions. It is better to shoot horizontals rather than verticals.

PHOTOGRAPHY IS A STATIC MEDIUM, but the underwater world is always moving. One of my favourite ways to capture this feeling is by using long exposures.
The key is to drop our shutter speed to a range of 1/15th to ¼ of a second, while still producing a good exposure in the background. This is long enough to create blur, yet short enough to be precisely controllable. I use this range for all the techniques below.
On a sunny day it’s a challenge to use such slow shutter speeds without massively over-exposing the background. This is the main reason I look forward to diving on rainy days, because the darker conditions are ideal for capturing motion blur.
Finally, I find it easiest to divide movement shots into those where the camera is stationary and those where the camera is moving, panning or zooming. This division helps us to choose the right technique.
As you may know, SLR and mirrorless cameras can be set to fire their flash at the start or the end of an exposure.
With normal fast shutter speeds the difference is not important, but when we slow down the shutter speed this feature becomes a valuable creative tool.
The camera’s default is to fire the flash at the start of the exposure, but second or rear-curtain synch fires it at the end. The latter is the traditional approach with long exposures, and is the way to go when we hold the camera stationary.

THINK ABOUT THE image-making process and you can see the advantage of rear-curtain. Imagine shooting a long exposure of a fish swimming over a reef. We hold the camera still and press the shutter. With standard front-curtain the shutter opens, the strobe fires and the fish continues to swim across the frame before the shutter closes.
The picture is disappointing because the fish looks as if it's swimming backwards, because the blurred movement extends forward from its flash-frozen image.
Rear-curtain is designed to solve this problem. Now when we shoot, the shutter opens and the fish swims across the frame, being frozen by the flash only at the end of the exposure. This means that the blur extends backwards, and looks much more natural.

SO WHEN SHOULD we use standard front-curtain synch? I actually use this mode for almost all my long exposures because it is best when the camera is moving.
With front-curtain the flash fires immediately we press the shutter, giving us exactly the composition we want.
We then generate the movement with intentional camera movement, through accelerated panning, zooming the lens or spinning the camera.
To avoid the problem of the fish looking as if it is swimming backwards we use accelerated panning, where we pan the camera faster than the subject, overtaking it and therefore making the blur extend behind it.
Moving the camera also exaggerates the amount of movement blur, which adds to the drama.
Zoom blur is a classic photographic technique created by zooming the lens during a long exposure. It creates characteristic lines exploding out from the subject.
Start with the lens at its widest angle, click the shutter and zoom it in. It can take a few attempts to get a good one, but it’s a fun challenge with everyday subjects.
The final option is the spin, which is made by rotating the camera during a long exposure. The challenge is to blend sharp, in-focus details on the subject with a blurred background.
Sharpness comes from lighting the subject, but not the background, with our strobes. So look for a subject that is a little away from the reef.
You don’t need to rotate the camera really fast – aim for the speed at which you would steer a car around a mini-roundabout.
Again, it takes a few attempts to get the spin centred on the subject, and it's easiest to pull off when not looking through the viewfinder!
I hope these ideas will brighten up those rainy days. But if all else fails, a helpful photographer suggested to me this: just head to the spa when it rains!

Certain subjects look at their best in the rain. Many anemones ball up under dark skies, revealing their colourful skirts and concentrating their anemonefish into a pleasing gaggle at the top.
Shoot them in horizontal compositions to avoid whiting out the surface of the sea.

When the weather is bad we should keep the window closed. Not just at home, but under water.
The large exposure difference between the surface and depth in poor weather means that we should keep Snell’s Window out of our shots when exposing for the blue. If not, it will white out.

The best motion-blur shots contain both sharp areas and blurred areas. This means lighting the subject with flash to freeze it and to have unlit details behind to blur.
A totally blurred image is rarely effective, as it leaves the viewer wanting more.