A Last Lights Questions (From me anyway)

[Graham O]

Well my new dynamo turned up yesterday from Germany. Ordered Monday and delivered Thursday. Well done www.roseversand.com. The big question now is about a front light. The choice is going to be either B+M IQ Fly Senso or the IQ Cyo. However I am a bit lost after reading their website. Am I right in thinking that the Cyo has 60 Lux output because it has a more concentrated beam than the Fly which has a more dispersed beam? There is a beam pattern for the Cyo, but not for the Fly. Any help much appreciated.

Of general interest, I've found the recent bit of information on an American site:

The output claimed is 40 lux at ten meters. As the light patch is about 12 square meters at this distance, this equals about 500 lumen worth of output...out of a 6V/3W dynamo hub...

The good thing about this is that it sums up the science of Lumens vs Lux. Lux is the density of lumens, i.e. lumens per square metre at a specific distance. This is much more useful than just Lumens as it gives some idea of the lights illumination properties, provided the beam pattern is shown or defined. So it is a bit frustrating that the beam pattern for the Fly isn't shown.

 

[PatrickPending]

http://en.wikipedia.org/wiki/Lux


personally I prefer irradiance, though I can see why others are used - taking into the response of the eye.....

 

[bikepete]

As I understand it there are two versions of the Cyo, both of which are somewhat brighter than the IQ Fly (due to various refinements to the LED and lens system, though I can't find the reference to that just now).

The first one has a built-in reflector (to comply with German regulations) which also modifies the beam pattern to cast more light down close in front of your front wheel. This is the 40 Lux jobbie.

The 60 Lux model has a clear lens instead of the one with reflector moulded in, and so throws more light forwards.

I'm not entirely sure whether there's actually a difference in output, or whether the light is just distributed differently between the two models.

Beam patterns are shown here:

http://bumm.de/index.html?docu/175q.htm

 

[Randochap]

lights

What kind of dynamo -- hub or bottle?

I couldn't find any on that site.

I run the Schmidt hub and recently replaced a dual-E6 set-up with the amazing new Edelux. It's a bit pricey but worth every penny.

The IQ Fly is a very good light, and, in fact shares the same optics as the Edelux. You'd be happy with either one.

There's a description of the light in use and link to the company's specs here.