Taillamp: Busch & Müller Secula

On the main page I wondered since ca. Oct. 2012 when I saw the Secula listed on the distributor's price list:

Could this improve on the old SP15 with incandescent bulb?

I expected the Lightring to be like this...


StVZO approval no: K976 & K977
Mass: 39 g (with washer and nut).
Size: 40.8 mm width, 60.0 mm height, 39.5 mm thickness.
Light source: 1 red LED?
Mounting method: On the rear fender.
Cabling/connectors: 2 connectors for a dual strand cable with 2.8 mm plugs.
Construction: Plastic, housing looks to be glued, the black clip on top doesn't seem to have a purpose, with steel bolt + nut + washer.

Price: ca. € 18,-


Beam shots

See the camera settings page for more on the setup and settings to make pictures of the beams of taillamps.

Out of a corner (showing how much light is cast upwards, forwards and to the sides) [ F3.9 & F1.8 ]:

Wallshot (showing the beam pattern):

Visibility from various angles (0°, 45°, 90°, 135°) [ 0.5m, zoom x3, F3.5, ISO80, 1/250s & 1/60s ]:

Comparing taillamps


The Secula does what it should do, give plenty of light without being annoying, the reflector is lit up too. This is a concept that works, besides of course the other possibility to get a large lighting surface, which is lighting up the entire reflector with enough intensity that another lit surface area such as a ring of light is not needed, but such taillamps don't exist yet.

On the beamshots you can see that it produces a lot of light. The Secula puts out a lot of light to the sides, which is good, possibly one of the best in this respect. But this light production is not achieved with little power. Power draw on DC is about 70 mA which is very high, about 5 times as much as the Lumiring or the Line plus... But imagine now what could be done with the same power: I could run 5 Lumiring taillamps in various directions which would give way better visibility. So this taillamp is not at all optimal with respect to power used.

Note: This is the first taillamp I made beam shots of with the RX100 camera, so I made some new pictures of the Lineo taillamp (RX100: F4 ISO 200 0.5s & F4 ISO 200 2s) to compare with those I had made long ago with the EX1 (EX1: F3.9, ISO 80, 1s & F1.8, ISO 80, 1s). A picture made with the RX100 at the F4 ISO 200 1s seems more equivalent to the low setting with the EX1 (so RX100: F4 ISO 200 0.5s seems a bit dimmer than EX1: F3.9, ISO 80), even though the RX100 setting gathers a bit more light... And the F4 ISO200 2s picture seems also a bit dimmer than the EX1: F1.8, ISO 80, 1s picture. I will think about how to deal with this. Perhaps increase the exposure time for the RX100.

2017-1-5: Updates on the Secula:
1. The mounting for any fender mounted taillamp should be stainless steel, not standard steel which is esp. important for fender mounted taillamps as there a lot more water gets onto the bolt... Mine was rusted so badly that in getting off the nut, the bolt is now loose in the lamp, so I will cut it open soon.

2. A reader mentioned that the battery powered version of the Secula has bad weather proofing, and the switch far too easily switches the lamp on, already doing so 'when you look at it' ;-) That's bad for battery powered lamps, you don't want your batteries drained and then to cycle without functioning taillamp!


The first good fender mounted LED based taillamp.

Very good visibility, optics are good (though to the rear not as good as the optics of the Lumiring). Power use is high. The mounting bolt is bad, it definitely needs to be stainless steel for a fender mounted taillamp, even more so than with a rack mounted taillamp.

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