Which light is brighter?

[gaz]

One light claims to output more than twice as many lumens as the other, but which is which?

 

[The Brewer]

Worried that Gaz is using red lights

Right seems a little brighter from the first pic

 

[gaz]

Worried that Gaz is using red lights

Right seems a little brighter from the first pic

These are rear lights :P

The right one is in fact the light that is rated as the less powerful of the two.

 

[MrJamie]

What lights are they and are the beam angles very different? The 2nd shot of the wall looks much bigger coverage, although it's hard to judge brightness from photos

 

[gaz]

What lights are they and are the beam angles very different? The 2nd shot of the wall looks much bigger coverage, although it's hard to judge brightness from photos

The light which claims to be brighter has the tighter beam angle (first of the wall shots).
The other one has a much wider spread for several reasons, one being a diffuser lens.

The two wall shots are taken seconds apart from the same location and with the same exposure, shutter speed and iso. Although I wasn't using a tripod, hence the slightly different line up of the shot.

 

[Matthew_T]

I was once riding down the coastal path and noticed some people setting off fireworks. I watched them for a little while and then noticed a couple watching them too. I went over and asked them how long the people had been setting off fireworks. They said they just turned up and started doing it.
The couple then said "We thought you were a train with that bright light". It cracked me up. It was soon after I had got it and it is mighty bright.

TBH my commute is starting to enter the daylight hours on the return leg (I leave college at about 8pm) so the need for lights is becoming lesser. I also have only a month left of commuting.

 

[GrasB]

CCD/CMOS sensors are more sensitive at longer wave lengths (towards the red end of the spectrum). So on my D70, for instance, an Osram deep red LED looks brighter than it's normal red counter part, however a human's eye says that the normal red LED is brighter! Also before anyone can make that call from those photos people need you to take a photo of the lights which aren't fully saturated (your first picture). Then we need the following information:
The nominal LED wave length
The LED spectrum spread
The IR cut off filter wavelength
The CCD/CMOS sensor in the camera
The red quell balancing algorithm of the camera

Only then does anyone have a chance of really answering your question. It would also be nice to have the luminosity plot of the lenses used on those lights. A tight centre beam may be hiding a higher luminosity at extreme angles - throwing 30% of your lumen out in the +/-80 to 135 deg band will significantly reduce the centre spot brightness compared to a lens which has 0 illumination beyond +/-90 degrees.

 

[shouldbeinbed]

The light which claims to be brighter has the tighter beam angle (first of the wall shots).
The other one has a much wider spread for several reasons, one being a diffuser lens.

The two wall shots are taken seconds apart from the same location and with the same exposure, shutter speed and iso. Although I wasn't using a tripod, hence the slightly different line up of the shot.

you can see that in the facing shot too, its centre (lets call it) white area is more compact than the right side one too.

more general blather

I think light intensity gets to a point where extra is just unneccesary, you can see & be seen clearly at 'x' lumens; as long as mounting angle etc is right; but manufacturers have to bring out new products to stay in the users perception and those new products have to be sold. 'Look at how bright this one' is tends to be one of the faux USP that they use to persuade us to part with our cash.
I guess theres a point at which the human eye & brain hits sensory overload and lacks the facility to differentiate as well as a benchmark lightmeter test too, so you end up paying for what you can't actually derive a safety benefit from and if its blinding a following driver or bleaching out the scene in front of you could be doing you more harm than good.

I tend to buy lights that are of a decent illumination but which have other factors going for them, waterproof, solid mount etc

 

[GrasB]

you can see that in the facing shot too, its centre (lets call it) white area is more compact than the right side one too.

more general blather

I think light intensity gets to a point where extra is just unneccesary, you can see & be seen clearly at 'x' lumens; as long as mounting angle etc is right; but manufacturers have to bring out new products to stay in the users perception and those new products have to be sold. 'Look at how bright this one' is tends to be one of the faux USP that they use to persuade us to part with our cash.

The problem is we're thinking in lumen where actually we need to think in lux of the apparent light surface. A friend of mine is looking into making his own rear light & found that the typical car rear light is something like 1000 lumen, HI rear lights are nearer 2500-4000 lumen & brake lights are typically 10-20% higher than the HI rear. Those very high lumen figures are the reason you can see car rear lights at large distances. However that's only half the story. Because of the large surface area they are no where near as intense at close range.

This is the problem with bike lights, if the light isn't to intense at close range the lumen are to low to be effective at distance (which is required for effective light on 50mph & NSL roads) but if it's bright enough to deal with the distance issue the apparent source is too intense at close range.

 

[Matthew_T]

Is there any legallity about how bright a bike light can be? I have had people flash me before when I have had my light on full (when I first got it I had it on full on the roads).
I know it is polite to turn down the light when you see a car coming but what is the legality on the actual brightness? My light claims to be 1800 LM (doubt that) and there are people on here with much brighter.

 

[fossyant]

Which lights have you there Gaz - I assume one is a magicshine ?

Got myself two c&b seen jobbies now - OMFG !

 

[fossyant]

Is there any legallity about how bright a bike light can be? I have had people flash me before when I have had my light on full (when I first got it I had it on full on the roads).
I know it is polite to turn down the light when you see a car coming but what is the legality on the actual brightness? My light claims to be 1800 LM (doubt that) and there are people on here with much brighter.

No law as such, but it's not good practice to dazzle other road users. Your light being a Magicshine clone T6 will be about 700 lumen, not 1800.

 

[siadwell]

Is there any legallity about how bright a bike light can be? I have had people flash me before when I have had my light on full (when I first got it I had it on full on the roads).
I know it is polite to turn down the light when you see a car coming but what is the legality on the actual brightness? My light claims to be 1800 LM (doubt that) and there are people on here with much brighter.

Highway Code rule 114:

You MUST NOT

• use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders
• use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves to avoid dazzling other road users (see Rule 226).

In stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights. This will minimise glare to road users behind until the traffic moves again.
Law RVLR reg 27

The HC itself is not law, but MUST and MUST NOT rules are backed up by law, in this case Road Vehicle Lighting Regulations.

 

[gaz]

Which lights have you there Gaz - I assume one is a magicshine ?

Got myself two c&b seen jobbies now - OMFG !

Nope. one of them is c&b seen rear light. I doubt it is what it claims.

 

[BSRU]

I had a driver complain about my rear light once, a Dinotte, 200 lumens, the irony of the situation was I was behind a new mini with a driver who had their foot on the brake pedal, new mini brake lights a way brighter than my Dinotte,
The complaining driver did not complain about the mini's lights and shut up when I pointed out there car related blindness.