Explanation

Location for comparison

All photos show Sandtunel in Hirlatzhoehle behind Sandbiwak when going inwards. The yellow bag has a distance of about 10m from the caver, orange one of about 20m and the most distant part of the wall is at about 30m.

This part of the cave is dry and reflects quite well, i.e. it looks light. This place is suitable to compare normal Work-Lights, which you will use most of time when moving in a cave. It is also suitable to campare the ability to illuminate big halls, even though this room is not realy large.

This place is not suitable to campare spots or throwers, because there is no narrowing in the foreground, which may blind you. In this room you definitly do not need any spot. Some cavers even think, that in general there is no need for an additional thrower.

Conventional headlights

Carbide lamps had a relatively large flame. Therefore they didn't blind, even if you look directly on them. The disadvantage of a big source area is, that focussing is not possible - but on the other hand any reflector would be smoked black in short time anyhow.

LED have a source area of only 1mm², thus their light can be focussed easily - but most commercial LED headlights blind extremely! Focussing is good for illuminating narrow shafts in the ceiling or deep pits. But it is not so good for normal walking around and climbing.

The beam of most commercial headlights are too narrow, as we demonstrated in 'Old Comparison' at the example Petzl Ultra. Scurion is a laudable exception, it offers a roomlight comparable to carbide lamps (bare emitter, 125° FWHM, full width half maximum). Additionally it provides a thrower too (about 8°) Both sources can be used separately and/or in combination.

Unfortunately this combination is not optimum: the roomlight gives not enough brightness fare in front of you, because it illuminates areas too, which are of no interest for the bearer. The additional thrower cannot compensate this, because it is too narrow, as you can see on the photo 'Scurion, 3|1'.

Possible Improvements

New testdevice 3 has a roomlight reduced to about 80° FWHM softly and tilt down by about 30°, sufficiant to illuminate all you need to see during moving around with high efficiency. The spot is a soft meadium beam (25°) and not tilt. Thus it can compensate the weakness of the roomlight fare in front of you smothly, as you can see on the photo 'New testdevice 3, Work-Light 2'.

Since the thrower is now no more a real spot, the new testdevice provides an additional thrower with sharp edge (9°). This will never be used together with the two other lights to avoid blinding by the foreground. The medium beam allone is used for Hall-Light with maximum power (both other LED off).

Blinding of Work-Light is much less with New testdevice than with Scurion.

If you are interested in technical details, please read the expert discussion in Candlepoweforums (it is very extensive!)