I have been looking for the solution with the mobility, especially with the good proportion of illuminating power, weight of the lighting equipment and the time effectiveness. The additional need was also the ability of zoom in and zooms out of the beam, which would allow reaching the part of the cave which was not accessible by foot.
I was testing the Microfire Warrior xenon torch with the power of 35w and 3500 lumens in the summer 2008. Great torch but unfortunately not appropriate for cave lighting as it was not possible to correct the power of the light in close and far distance. The enclosed accumulator gave only a bit less than an hour of effective use.
I bought Led Lenser X21 torch with about 1000 lumen in February 2009. Intensive ground work and testing gave very positive results. The torch is with enough lumens, possibility of zoom in –zoom out of the light beam, it is relatively light (1.5 kg) and with the effective use of over 10 hours with 4 alkalis D type batteries. That means that is appropriate even for the cave expeditions to remote areas where no chance to fill accumulators is.
I tested Led Lenser X21 in huge volume caverns and tunnels as it is Planinska jama from the entrance to the subterranean confluence of Pivka and Rak Rivers which is the greatest subterranean confluence of rivers in Europe, the entrance hall of Križna jama and huge Dolines of Zelške jame. The results were excellent. It is interesting that the result was fine even in Planinska jama which is problematic with the photography due the haze.
The test of robustness and effective time use followed in more extreme conditions. I have got a permission from the Ministry of the environment to enter Nova Križna jama, which is cave with very sensible habitat with the unique ecosystem and is with the highest level of the protection. The entry was allowed only for scientists and researchers with the special permission.
The progress of the technology and the handy use of the X21 were noticeable with the fact that I did in few entries into this cave in February and March 2009, the same or event more work than in previous years of stage entries from 2000-2003.
Last decade wasn’t only with the revolution of digital cameras but also with the technological revolution of effective conversion of electric power into the light.