A set of prints after the trip works wonders, as does buying an extra round in the pub after the trip. Wensleydale Just getting there can be a problem. A waterproof camera box is essential. Once beyond daylight underground, flash guns provide the only practical form of illumination in British caves and mines. Whilst bulb flash guns have a greater light output and duration, most shots are taken with electronic flash guns.
Electronic flash is cheaper and far more widely available.
The disadvantage of this light source is it's aversion to humidity, but nothing the resourceful caver can't get round. The first important decision the cave photographer needs to make is what he wants to photograph and how it should be lit. With no other light sources available, the photographer has almost complete control over the lighting. The current state of the art uses a flash gun mounted on the camera, but covered with an Infra red filter so that no visible light is emitted. The slaves then fire from the infra red pulse of light.