LET THERE BE LIGHT!

Above, from left to right:

• Fenix TK30 White Laser, LEP, Beam Reichweite 1200 Meter, 500 Lumen, 250€
• Noctigon KR4, 4 x SST-20 4000K, 95 CRI, 3000 Lumen, 55$
• Ultrafire Infrared Flashlight, 5W IR LED, 20€
• KDLitker E6, orange, light blue, white 3000K, 25€
• Fenix LR35R, 10000 Lumen, 200€
• Convoy S2+, purple, orange, green, 25€
• Emisar D18, 18 x SST-20, 4000K, 95 CRI, 10000 Lumen, 109$

Below:

• Ryus Lightworks Light Painters Flashlight, 115€
• Fenix PD36R, 1600 Lumen, 100€
• Emisar D4V2, 4 x SST-20, 3000K, 95 CRI, 45$
• Lumintop Tool AA Titan, 650 Lumen, Nichia 219CT, 4000K, 70€ (Aluminium 25€)
• Convoy S2+, Osram UV-Led, 40€
• Noctigon DM11, SST-20, 4000K, 95 CRI, 1200 Lumen, 60$

BRIGHTNESS

Many manufacturers of torches, especially the not so good ones, like to write the highest possible luminous flux specifications on the packaging or in the flowery descriptions on the website. Ultimately, the lumen rating is not very meaningful. On the one hand, the intensity of the light that reaches the illuminated spot depends on the angle of radiation. The Fenix TK30 with its meagre 500 lumens illuminates parts several hundred metres away very brightly. The beam angle of this torch is only a few degrees. This means that the light cone is very narrow. The opposite of this is the Emisar D18 with a very homogeneous light cone that is approx. 80° wide. The range is about 50 metres. But the illuminated area is very large.

Whether the brightness stated by the manufacturer is achieved in reality (if it is true at all) depends first of all on the battery. The small D4V2 is powered by an 18650 battery. The four SST-20s have a total electrical output of 40 watts. In addition, there is the power loss of the driver. In total, the battery has to supply about 45 watts. This results in a current of 12 amps (45 watts / 3.7 volts). Most 18650 batteries cannot deliver this current permanently. Therefore, the maximum possible luminous flux is not reached. When buying batteries, it is therefore important to ensure that they can supply the necessary continuous current. The maximum pulse current is often specified. Even if this is stated as 20 or 30 amps, this does not mean that the battery can permanently deliver the continuous current required in the example above.

The brightness of most torches is regulated depending on the temperature in order to protect the electronics of the driver, the LED and the battery from overheating. The maximum brightness is therefore not permanently available with most torches. How quickly and how far the brightness is reduced depends on several factors. First of all, the quality and efficiency of the driver. The more heat loss it produces, the faster the torch is turned down. The second aspect is the thermal conductivity of the housing. A small housing made of titanium or stainless steel conducts heat much less effectively than a large housing made of copper or brass. I find it much more important how stable the second brightest level runs. With most good torches, this runs for 20 minutes or more without the brightness decreasing significantly. For light painting work, this is an important aspect.

It took over 17 minutes to illuminate the huge hangar. If the brightness of the Emisar D18 had decreased significantly during this time, the work would have been much harder or the result worse.

COLOUR TEMPERATURE AND COLOUR RENDERING INDEX (CRI)

I lit the rusty Dutchman in complete darkness with the 3000K Emisar D4V2. The torch’s colour rendering index is 95. For comparison: candlelight has a CRI of 100, sodium vapour lamps (street lamps) have a CRI of 35 to 40 and the ugly Led Lenser torches usually have a CRI of no more than 70. This value describes how well and how vividly colours are rendered when illuminated with the torch. The colour temperature also has an influence on the result. Cold white light with 6000K or above is usually very unattractive. Neutral white (4000K) or warm white (3000K or lower) are perceived as much more pleasant by the human eye. When buying a new torch, one should always pay attention to the colour temperature and also the CRI. In most cases, manufacturers specify the former, but unfortunately often not the CRI. However, if the CRI is above 90, this is a purchase argument for many people. For this reason, the manufacturer will advertise the torch with the high CRI. If this information is missing, the CRI will probably be quite low.

SIZE, WEIGHT, MATERIAL

Most torches are made of aluminium alloys. Aluminium is a passable heat conductor, inexpensive and quite easy to machine. Torches made of titanium alloys are much more robust than specimens made of aluminium or copper. You can probably drive over the small Lumintop (middle torch in the picture) 38 times in a crowded bus without damaging the torch. Titanium, however, has two very decisive disadvantages. Titanium is a poor conductor of heat. For this reason, the area of the housing where the driver sits is made of brass. Besides, the stuff is very expensive. The small Lumintop costs three times as much in the titanium version as the same torch made of aluminium.

In principle, it is of course very pleasant if the torch is as small and light as possible, but only to the point that the function is not restricted. The lighter the material, the faster the torch reduces its brightness. In addition, the runtime of the small Tool AA with the small 14500 battery is of course significantly shorter than that of a torch with the same LED and a large 18650 battery.

BEAM

The picture shows two Emisar D4V2s. On the left with floody optics, on the right with clear optics. Both torches are flooders, i.e. they illuminate a large area very evenly. The matt “floody optic” intensifies this effect.

Emisar D4V2 4000K floody optics

Noctigon DM11 4000K

Fenix TK30 LEP

Fenix PD36R

The differences are clearly visible in the beamshots. The distance between the torches and the cellar wall was the same in all shots (approx. 4 metres). The Emisar illuminates a larger area than the camera shows. Unfortunately, my cellar is not larger. The small Noctigon DM11 thrower only illuminates a very small area and therefore a very large range. This effect is even more pronounced with the TK30. However, this is not a normal torch. A phosphor layer is stimulated to glow with a blue laser. This light is then directed forward with mirrors and lenses, bundled and emitted from the head of the torch. LEP torches are currently not available in the European Union. Fortunately, I bought mine a few years ago. The last beamshot shows a classic EDC torch. It illuminates a small spot in the middle very brightly and a larger area around with low brightness. For normal use, this is quite useful. In the dark forest I can see what is coming at me at a distance of 30 to 40 metres and at the same time I don’t fall on my face because the area in front of my feet is still brightly enough illuminated. However, EDC torches are less suitable for illuminating light painting. I would always prefer a classic flooder. And then there are torches with zoom. No one needs such a thing any more. Led Lenser is pretty much the only manufacturer of such torches. All these torches emit a very ugly light. The LEDs have a colour temperature of 6500K – 7000K and a very low CRI. Furthermore, the Led Lenser torches are very expensive. At the latest with the permanently installed special batteries and these strange magnetic charging parts, I am completely out. So stay away from Led Lenser, no matter how many important light painters tell you that you absolutely need them for light painting.

USER INTERFACE

Sven Gerard

Sven Gerard, Jahrgang 1969, geboren und aufgewachsen in Berlin. Er fotografiert seit frühester Jugend mit großer Leidenschaft. Neben dem fotografischen Erkunden zahlreicher beeindruckender verlassener Orte, widmet er sich seit mittlerweile 10 Jahren intensiv dem Lightpainting. Sein umfangreiches Wissen teilt er auf seinem Blog „Lichtkunstfoto.de“, weiteren Publikationen und in seinen Workshops. Darüber hinaus organisiert er Veranstaltungen zum Thema Lightpainting, wie „Light Up Berlin“. Gerard lebt gemeinsam mit seiner Lebensgefährtin in Berlin und hat einen erwachsenen Sohn.

Sven Gerard was born in 1969 and grew up in Berlin. He has been a passionate photographer since his early youth. In addition to photographically exploring numerous impressive abandoned places, he has been intensively involved in light painting for 10 years now. He shares his extensive knowledge on his blog ‘Lichtkunstfoto.de’, other publications and in his workshops. He also organises events on the subject of light painting, such as ‘Light Up Berlin’. Gerard lives in Berlin with his partner and has a grown-up son.