Oxford University Cave Club1989 "Juracao " Expedition Final ReportPicos de Europa, Spain |
Contents |
by Graham Naylor
The idea of making a film of the expedition was initially conceived in late 1988. It was a way of telling the story of OUCC expeditions after the success of the book "Beneath the Mountains''. After considering the various image recording media, it was decided that video would be most suitable in view of its sensitivity under low lighting and ease of operation.
A video camera was duly hired for a weekend to gain some experience of underground filming. As lighting we tried using camping gas lights, multi jet carbide lights and quartz halogen lights powered by lead acid rechargeable batteries. Within ten minutes of entering Sunset Hole all that could be seen through the view-finder was the word "dew''. A hasty retreat was made to the Hill Inn for a rethink and to dry out the camera before returning it. From this initial experiment several things became clear. Underground filming was very difficult, a video camera for underground use should have some degree of waterproofing and camping gas lights were pretty useless. The most convenient light source was found to be quartz halogen lamps. The bulb was defocused in the reflector and a diffusing screen over the front was used to produce a wide area of uniform illumination. A 100W unit and several car headlamps and "task lamps'' of 55W each were used. These were powered by sealed lead acid batteries (6.5 and 15Ah) packed in ammo cans. A Sony SP5 video 8 camrecorder was used since its housing was sealed against falling water and dust, and very well it performed too!
After a few practice trials in the UK we joined the expedition in Spain to take the shots. A wide angle lens was added to the kit to shoot the shaft series. The camera was stored in a large ammo can to carry into the cave and protect it between shots. This box proved to be a complete b*****d in the rifts and carrying the lead acid batteries out from 800m was quite exhausting. About 50 minutes of underground footage was taken on a one day trip and one three day camping trip. Two rechargeable Ni-Cad batteries were used for the camrecorder and were recharged underground from duracells (two 4.5V duracells, in series, charged a 6V Ni-Cad with just less than 1A constant current limited by the internal resistance of the duracells). An hour of video was taken on the surface over a few days. The video has been edited onto VHS tape to produce a sixteen minute film of the expedition.