Old 10-11-09, 11:30 AM
  #23  
2_i 
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Originally Posted by PaulRivers View Post
Personally, I wouldn't assume it was a technical issue (especially after they've gone to so much work to shape the beam), I would assume most of these companies believe consumers prefer to have more light up ahead rather than less light up ahead and more light close to the bike. Or alternatively, it's not unreasonable to think that perhaps they figure everyone buys lights based on the lumens/lux rating, and they can give it a higher lumen/lux rating by concentrating more farther ahead of the bike rather than lighting the area immediately in front of it, thus doing it for no reason other than marketing.
I think that, on one hand, you underestimate the complexity of the optical problem, both from the mathematical and engineering points of view. On the other hand, most of the successful manufacturers of dynamo lights are in Germany and Switzerland and the bulk of their customers are in those 2 countries + Austria, Netherlands and Denmark. I do not think that the riders in those countries get primarily swayed by the lux values more than anything else - the societies there tend to be more multidimensional in a variety of ways. E.g. many might be bothered by the fact that they could blind the passer-bys.

Originally Posted by PaulRivers View Post
I think this is most likely the crux of the issue. If I go twice as fast, I need to be able to see...twice as far ahead? The beam can have twice as big of a gap in front of it for me as it can for you. Likewise, what you consider "increase in the range that one anyway barely sees" is for me the part of the road I really need to be able to see when cruising down a hill, and it's rather nice when I'm on the flat, to.
That is clear, the distance over which one looks reflects the reaction time. The faster you go, the farther you need to look. However, even a fast rider may eventually reach a difficult terrain where he needs to slow down and look over nearby details.

Originally Posted by PaulRivers View Post
Because on a dynamo light you only have so much power, so if you use light in one place that means you've lost it somewhere else.
Surprisingly, IQ Cyo consumes less than a third of the power of an incandescent lamp. I wonder whether Edelux consumes more. There is a lot of power that could be utilized e.g. by an additional emitter.

Originally Posted by PaulRivers View Post
I don't really disagree that it would be rather nice if they illuminated more of the road close to the bike. When I first got the light, I remember thinking that it would nice if that gap between the main part of the light and the front of the wheel were lit up about twice as much. But we disgree on whether this is a really important issue or just an annoyance.
Sure.

Originally Posted by PaulRivers View Post
I think you missed the reason I was making the comparison. What I was saying is that while I haven't myself used the Cyo Nearfield (40 lux), I have used another light that has the same lux rating and uses the exact same beam pattern, minus the nearfield part. I used the lux rating simply to say that I used another light that should, theoretically, put out exactly the same amount of light as the Cyo nearfield. And I felt it didn't put out an intense enough light to really light up the road so I could see small hole, twigs, etc. I was saying that I imagine I would have the same feeling with the light intensity of the Cyo nearfield.
Well, I made a mistake thinking that Ixon IQ was an earlier LED lamp by B&M and so could have had less developed optics. Looking closer, it appears that it has similar optics to IQ Cyo Sport not Cyo R, as it lacks the refractive lens. Here we could argue again why Ixon IQ fails to illuminate near-field. You would say that this was because of a too low lux-value. I would say because of the beam shape. Bisy has no problem illuminating near-field with only 17 lux.

Well, we are coming to this:

Originally Posted by PaulRivers View Post
This also relates to why I would or wouldn't insist that the light lights that gap in front of the bike - I think it would nice if that area was lit up more (while you find it very important), but I wouldn't be willing to give up the greater intensity in the main area of the beam, which I find is very important (though you do not).
It is OK, maybe even unavoidable, to differ in these or other priorities.
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