A common topic I get asked about is how to do split shots or half-halfs.
Here is a fairly typical example of this kind of shot below. I shot this on one of our Maldives workshops earlier this year, and it pictures a diver waiting on his safety stop with a Maldivian island in the background.

Split shot in calm water of UW photographer on safety stop.

Split shot in calm water of UW photographer on safety stop.

This was grabbed on the fly so to speak and there was no planning beforehand.
I had realised at the beginning of the dive that there may well be an opportunity for this sort of shot, because of the fortuitously placed tropical island, but it was entirely luck that the diver happened to be in a perfect position to pull this off successfully.

Split shots require a fair bit of patience and the conditions need to be in your favour. Ideally mirror calm seas.And with the sun preferably behind you.This is because you are going to have to place the waterline along the centre of your dome port or additional lens, and its better to have the sun behind you because its much easier to balance your exposure this way.
The bigger the dome the better and easier it is to do, but I usually shoot with a very small 4inch dome, which is a popular dome these days, with shrinking cameras and housings,fast replacing more conventional larger DSLR setups and huge domes.
I put loads of air in my BCD, to make sure I am held high in the water, and my technique is to “shoot from the hip”
This is my friend Simon taking splits at the surface in this way.

ShootingFromTheHip

Which means I take a couple of test shots and review onscreen to see if I am somewhere close. I then fine tune my positioning in relationship to the subject, and fire away.Even with flat seas there are still small waves to contend with so there is a random aspect to all this, so take as many shots as you need, and have time to do.
This is my split of Simon in the foreground and the boat in the background, im betting he has a pretty similar shot!

My shot of Simon and the Dhoni in the background, whilst we wait for our turn on the ladder

My shot of Simon and the Dhoni in the background, whilst we wait for our turn on the ladder

Exposure wise I try and balance the exposure with a small emphasis on slightly,( and I mean slightly) overexpose the top half of the shot. If you overexpose too much then it’s almost impossible to recover the highlights in your shot afterwards, this is another reason to take a few test shots, to get this aspect correct.
It’s a good idea to shoot in RAW format too because you will have more scope when editing if the exposure balance is very wide.

All being well you should get some results, don’t be too disheartened if they don’t work out first time. Review where you went wrong and have a bash next time the opportunity arises.
Speaking of ideal opportunities, when you are ready to board the boat and are waiting your turn for the ladder, this is a great place to have a go at some splits. There is usually subject matter both below and above the waterline to liven up your composition.This shot below was achieved with a compact camera and an add on lens. This is more difficult to pull off, because as you are moved around by the waves, and the small waves are splashing over the very small add on lens there is a random element to all this so take lots of pictures. With external add on lenses you also have to dunk the camera below the waterline quickly to fill the space with water between the lens and the front of the housing, and then quickly take your shot before the water drains out.There was quite a discrepancy between the white paintwork of the boat and the below water part of the shot, so having this shot in RAW enabled me to recover the information better than a Jpeg. So it’s great when you pull it off, very achievable though, just need to be a bit patient and not get disheartened when it doesn’t work. I have hundreds of shots that didn’t work!

A split shot at the back of the boat, shot with a Sony RX100 and a Fix Fisheye Lens.

A split shot at the back of the boat, shot with a Sony RX100 and a Fix Fisheye Lens.

The previous two shots have both been achieved with only the available light at the time. Another more advanced type of split is if you use your strobes to help light the bottom half of the shot. This only works when the bottom half subject is relatively close to you. You also have a more practical issue to think about in managing the weight of your strobes just at the waterline, so this is maybe a type of shot you may want to plan more ahead. I recently saw Alex Mustard and some of his workshoppers at The Barge at sunset, doing these sort of splits, and made a mental note to do the same thing with my bunch on our Winter Warmer trip in early 2014. And of course sunset or sunrise livens up the sky.
This Barge is ideal as there is a shallow reef just below the surface, and the sun goes down or up very near to where the boats are moored.
I had a go very early morning with mixed results, and will perfect it on the next trip there in February, but for now here is my strobe split attempt of a diver, I have positioned one strobe above and one below,tweaking their output to match the subject, it’s definitely easier doing this sort of thing with a smaller camera set up as the weight above the waterline makes things trickier with a full blown rig.

A split shot using strobes above and below the waterline

A split shot using strobes above and below the waterline

In all you can probably work out that there is a random aspect to shooting splits as it’s almost impossible to control all the variables. Please don’t let that put you off though some of my personal favourite splits have been the very random ones, they often have a more dynamic and active feel about them. And as you can see it’s not impossible just more difficult with a compact camera rig than it is with a large domed camera housing rig, so when you get a good shot give yourself a big pat on the back for pulling it off.