Hope 1 v Ayups

[mattybain]

Ah, suddenly everything is clear (or possibly coated with jam)

So the missing factor is the area they are measuring the light over? without that it's pretty meaningless!!

 

[downfader]

I just fitted the dynamo powered Cyo IQ, and even though it's the one with the reflector (so 40 Lux instead of 60) it is absolutely awesome. The great part is that the LED faces backwards, and is shaped by a reflector which gives a brilliant throw right across the road in a trapezoidal shape like a car headlamp, and which lights the ground right below your wheel- I don't have anything to compare it to myself, but I have seen people with powerful normal LED headlights and their beam is much more centered on a small circular spot, good for helmet mounting but gives you a smaller spot if on the bars.

About the blinding drivers bit, the IQ also cuts off the top of the beam like low beams on cars which means it doesn't blind people despite being so strong, I'm thinking about helmet mounting a hope adventure 1 (the wee version of the vision 1!) if I go on wee cycle paths at night, because with the IQ you can't see low branches and signs so well... or bats!

I'd like to compare it to hopes and ayups in the flesh though, they were my other two choices before I went for this!

Excellent post, that light sounds fantastic.

I currently use a cateye 5xx model (forget which). Very bright but needs to be angled down closer than the standard 10 feet distance you're supposed to aim for. Its frankly no good for seeing the road by, the spot is the size of my fist on the road and despite the quoted 1200 lumens it seems no where near as good as the more expensive models.

My mate at work went to Shirley Market here in Southampton last week and picked up a front light for £3.99. 5x LEDs, good side vis and good throw, quick release too. Quite impressed

 

[sunnyjim]

So the missing factor is the area they are measuring the light over? without that it's pretty meaningless!!

Correct.

What you want to know is:
1) How much light do you get for the money –total lumens emitted in all directions.
2) How is that distributed over the beam.
For a simple spot type lamp, it’s enough to quote the peak intensity (usually at the centre) and the half power angle, so you get a good idea of the beam divergence.
More complex beam shapes are specified as the intensity at a set of points at different horizontal and vertical angles. Eg EN/BS 68010 for vehicle lights.

The intensity at any point is expressed as lumens/steradian* or candelas, and is the local intensity at that angle in the beam only. (ie how bright it looks if you’re standing at that point in the beam looking directly at the source)

1 candela gives intensity of 1 lumen/sq m (=lux) at a distance of 1m from the source, or 0.01 lux at 10m from the source & so on. Hence knowing this distance is pretty important if someone’s quoting output in terms of lux.


*Steradian is a measure of solid angle –there are 4*pi in a sphere.

The units are well defined and intended to measure exactly this sort of thing, so the only reason I can think of for manufacturers giving confusing numbers is indeed to make it difficult to make quantitative comparisons rather than reading the bro-shoot.

 

[semislickstick]

Excellent post, that light sounds fantastic.

I currently use a cateye 5xx model (forget which). Very bright but needs to be angled down closer than the standard 10 feet distance you're supposed to aim for. Its frankly no good for seeing the road by, the spot is the size of my fist on the road and despite the quoted 1200 lumens it seems no where near as good as the more expensive models.

My mate at work went to Shirley Market here in Southampton last week and picked up a front light for £3.99. 5x LEDs, good side vis and good throw, quick release too. Quite impressed

Your Cateye will be in Candlepower not lumens.

1200 lumens should be very very bright from the impression I'm getting.
Now we are getting into adding Marmite on to the jam on the toast territory :-D.

 

[BentMikey]

... and from what I understand the LED lumens is often overstated - e.g. my Exposure MaxxD at 960 lumens might be a fair bit less than this due to less than best of bin LED quality, and losses in the lenses.

It's rather likely that some of the cheaper torches have a considerably smaller output than claimed too.

 

[downfader]

Your Cateye will be in Candlepower not lumens.

1200 lumens should be very very bright from the impression I'm getting.
Now we are getting into adding Marmite on to the jam on the toast territory :-D.

LOL you're probably right. I threw out the box ages ago.. all I remembered was the 1200 bit.

 

[RedBike]

Excellent post, that light sounds fantastic.

I currently use a cateye 5xx model (forget which). Very bright but needs to be angled down closer than the standard 10 feet distance you're supposed to aim for. Its frankly no good for seeing the road by, the spot is the size of my fist on the road and despite the quoted 1200 lumens it seems no where near as good as the more expensive models.

My mate at work went to Shirley Market here in Southampton last week and picked up a front light for £3.99. 5x LEDs, good side vis and good throw, quick release too. Quite impressed

I'm guessing it's the HL-530. In which case this light is nowhere near 1200lumens. You'd be lucky if it was 120lumens. It's rated at 1500 candlepower, which is yet another measurement.
Not that any of this matters.