Lights: how bright is too bright?

[BentMikey]

The crucial thing for dazzling people isn't actually the ultimate lumen it's the surface brightness of the oncoming light, in this regard the Maxx-D is no more powerful than the Joystick. The reason is simple while Maxx-D has 960 lumen output it's spread over 4 240 lumen LEDs, the Joystick has 1 240 lumen LED. So while the Maxx-D has 4x more output the surface brightness of the two lights is the same... the Maxx-D just has more surface area.

I don't think this is correct. I would have thought that the blinding ability of a particular light is dependant on how much light is reaching the observer, and not over what area the light is being emitted at.

 

[GrasB]

The source intensity defines how big the 'impact' is, the surface area defines how big a spot in the vision is 'impacted'. Yes the brighter Maxx-D will make the pupil contract more but the real lasting impact, which leaves you with a blind spot in your vision, is the residual image & that's down to light source intensity.

 

[2Loose]

Stop pointing them at peoples eyes!

 

[scouserinlondon]

Well one of my two $11 DX torches has started to give up the ghost. It was mainly off during my commute tonight. Time to admit defeat and ordered myself a hope 1. You get what you pay for etc...

 

[Sheffield_Tiger]

Stop pointing them at peoples eyes!

That's it, really.

"How bright is too bright" - well, there isn't a definitive answer. Even a £15 flashing LED light aimed directly at eye level could be a distraction, but a massive floodlight, if pointed down so it bounced off the road and lit you up in a pool of light like an escaping POW in the searchlight, ought to be fine

 

[knonist]

I was stopped in the middle of NCN11 (in Cambridge, an unlit stretch of cycle lane) last week by another cyclist saying my light is too bright.
I was using two LD20 on medium at the time and I need to see the road in front of me clearly for the new potholes; and before I got onto the NCN11, I had to cycle through 5 miles of unlit country lane.
Am I really too bright?

 

[HJ]

No, you just met the village idiot...

 

[Armegatron]

I was stopped in the middle of NCN11 (in Cambridge, an unlit stretch of cycle lane) last week by another cyclist saying my light is too bright.
I was using two LD20 on medium at the time and I need to see the road in front of me clearly for the new potholes; and before I got onto the NCN11, I had to cycle through 5 miles of unlit country lane.
Am I really too bright?

LD20 on medium shouldnt be too bright, especially if pointed down at potholes etc. I have one on my helmet on turbo and never get any complaints.

 

[scouserinlondon]

LD20 on medium shouldnt be too bright, especially if pointed down at potholes etc. I have one on my helmet on turbo and never get any complaints.

I have mine on the one below turbo on my lid, turbo for the sprint across the common.

Turbo is bloody bright.

 

[Wheeledweenie]

I was stopped in the middle of NCN11 (in Cambridge, an unlit stretch of cycle lane) last week by another cyclist saying my light is too bright.
I was using two LD20 on medium at the time and I need to see the road in front of me clearly for the new potholes; and before I got onto the NCN11, I had to cycle through 5 miles of unlit country lane.
Am I really too bright?

Perhaps it was the angle. Cyclists looking behind might be dazzled by something not too bad for motorists.

 

[Glow worm]

I was stopped in the middle of NCN11 (in Cambridge, an unlit stretch of cycle lane) last week by another cyclist saying my light is too bright.
I was using two LD20 on medium at the time and I need to see the road in front of me clearly for the new potholes; and before I got onto the NCN11, I had to cycle through 5 miles of unlit country lane.
Am I really too bright?

Not as bright as the cars whose driver's assume they don't have to dip their full beam for cyclists/ peds. Seems to happen all the time around here. Don't think you can be too bright on a bike if the lights are positioned correctly.

 

[GrasB]

Stop pointing them at peoples eyes!

My joystick is aimed so it's centre beam is hitting the ground about 7-8m in front of my wheel & even on Maxx (240 lumen) this doesn't seem to be an issue for motorists. However what kickecd off the brightness/dazzling discussion was this:

It's not about absolute lumen output it's about lux at the light source. If you compare a Joystick to a Maxx-D you have 1/4 the lumen produced over 1/4 the surface area. When aimed (in)correctly this surface brightness is more than enough to leave a nasty after image which lasts for about 30s or so, in this regards the Joystick actually manages to outperform all but the brightest car headlights on main beam.

The bit in bold is important.

 

[dellzeqq]

bright rear lights can be a bit of a pain on group rides, but some of the front lights are just too much. Wowbagger's front light turns off street lights!!!

 

[BentMikey]

What light has he got, Mr L3?

 

[fossyant]

bright rear lights can be a bit of a pain on group rides,

We've got a Bike to Work coming up again next week, and I'll stick to the rear with my Mars 4 and RSP Astrum.....not nice to follow on a bike...........