Equipment Overview

The environment and techniques of cave photography require the following capabilities of a camera to get the best pictures under demanding conditions:

• Manual exposure (all exposure settings in multiple flash work are controlled manually).
• Manual focus (in the dark wet non-reflective environment underground most autofocus mechanisms do not work reliably if at all).
• Ability to synchronise the shutter with external flashes (i.e. not built into the camera).

This does not mean you cannot use a camera which lacks any of these features, but a camera which features all of them is much preferred. Otherwise you will face situations where your camera limits the pictures you can take. So if you are serious about taking high quality pictures then I recommend you invest in a camera which supports these features.

The reason for this last one is that you need to get the flash off the camera. Even for single flash pictures. If the flash is built into the camera, or attached directly to the hot shoe on the camera then any water droplets in the air (mist and fog) will reflect the flash directly back to the camera, and your pictures will all come out foggy. Even if there is no fog, your pictures will look very flat as any shadow cast by the light from the flash will be hidden by the object casting the shadow. Get the flash even a little way to one side (or above or below the camera) and the fog should become invisible to the camera. Objects will cast shadows in the scene and the whole pictures springs to life.

This is the kit I currently use:

Camera
Canon EOS 5D digital SLR.
I also cave with friends who have the 20D, 300D and 350D models and all the advice here applies equally to any of these models. It most likely applies to all the other models of Canon cameras which have a hot shoe for using an external flash, including their compact cameras.

Flashes
Most large, cheap and manual flashes are perfectly suitable. The main issue is how you trigger them from the camera so that they fire at the same time as the camera is recording the scene without damaging the camera. More on this later.

Slave Units
These are remote triggers for the flashes. I have used radio remotes with limited success. Most reliable and commonly used are Firefly slave units developed by cavers for cavers. Another alternative is to use real live slaves (i.e. people!). These people manually fire the flashes on your command, but this requires a tripod and long exposure to ensure the flash is fired while the camera is recording the scene.

All this equipment needs protecting and operating (so you can't escape the need for real live slaves (or willing volunteers as we prefer to call them).