UK SL-6 & SRTH Turbohead--Lumens

OK, I still don't like it when numbers don't seem to add up with what I'm seeing...

I've got beam candlepower measurements down so that those numbers make some sense.

Back to the pine trees. I wouldn't expect the UK SL-6 to light them up as well as the SRTH Surefire Turbohead...and my expectations were met. The 9P with SOLA (as opposed to HOLA) doesn't do as well as the SL6 at the spot, but is much broader.

Here's the problem.

The SL6's spot is a LOT smaller than the SRTH.

There is little spill from the SL6 (no where near the coverage of the 9P SOLA (standard output lamp assembly -P90).

So why am I confused?

It's the LUMEN OUTPUT ratings now...

UK lists the SL6 as a 200 lumen light (actually, with data provided by UK, it lists as 201 lumens on Bright Guy's site).

The N2 is a 105 lumen lamp
The P90 is a 105 lumen lamp

Over their respective ranges, both 105 lumen SureFire lamp assemblies seem to give out more total light than the SL-6.

Thoughts?

Merry Christmas!

Richard

Just a question I can't find lumens rating on Bright Guy's Site, can you tell me where to find it?

It's not on all pages, but when you go to the detail page for a light, if it's there , it's in the tabular data on the right.

He's using manufacturer-supplied data, so lots'o'grains-of-salt should be handy.

See if you can find it for Underwater Kinetics's larger lights.

Merry Merry and to all a goodnight!

Richard

Thanks!

The bulb may be rated at 201 Lumens but what is the rating for what is leaving the flashlight.
SureFire rate their outputs as thoses measured from what is actually coming out of the flashlight. This value reflects (sic) the losses encountered and therefore is often lower then similar models from other manufacturers.

It may be a case of hyping for marketing etc but I have no proof and prefer to suggest that a more honest mis-representation is being used.

To measure the Lumens output of flashlights is an expensive investment that SureFire have made for themselves because they believe telling it how it is gives the users the ability to compare SureFire's own product range.

Al

Ah lumens, SL6, 7.5 volts 1.05 amps (on mine) that makes 7.875 watts. If you can get 200 lumens from a lamp with 7.875 watts, it's 25.75 lumens / watt. Which is pretty good. But I would prefer to aim for 30 lumens / watt with a 10 hour bulb life. 10 watt with 300 lumens would be good.

Good points, all! Nerd, you're on the right track here...so this is what I got on the other side of the equation.

Surefire 9P 7.45V 1.2A with P90 lamp assembly or 8.94W...rated at 105 lumens or 11.74 lumens/watt.

Hmmmmm.

Cheers,

Richard

If you look at the UK manual, it'll probably say, as mine does, "lumen value derived from theoretical calculation", or something to that effect. I love my SL6, but what this really means is that they pulled at least one number out of their a*& and that number was "lumens/watt".

So for all that's talked about lumens, you might as well just compare watts, because unless you're comparing within a product line, you're not going to get an accurate comparison
.

Originally posted by rlhess:
Back to the pine trees....

Click to expand...

<font size="2" face="Verdana, Arial">Richard,

Apologies if you've already mentioned this, but how far did you say those pine trees were?

Thanks,
Brightnorm

Originally posted by rlhess:
Good points, all! Nerd, you're on the right track here...so this is what I got on the other side of the equation.

Surefire 9P 7.45V 1.2A with P90 lamp assembly or 8.94W...rated at 105 lumens or 11.74 lumens/watt.

Hmmmmm.

Cheers,

Richard

Click to expand...

<font size="2" face="Verdana, Arial">Good points too, is it just that surefire lamps are inefficient? Not very possible if the beam is very white. Here's another thing I found, to achive 30 lumens / watt (not taking any reflector and outside loss into account here), you can take this lamp: http://www.walamp.com/detail.asp?partnumber=01171 and over drive it to 10.56 volts and get a 29.xx lumens / watt efficiency. That's pretty good for me. 10 hours and 438 lumens. That's 14.805 watts. Will the M*g reflector melt? I am seeing something here.... (wait, was that the idea from lemlux?)

Originally posted by brightnorm:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by rlhess:
Back to the pine trees....

Click to expand...

<font size="2" face="Verdana, Arial">Richard,

Apologies if you've already mentioned this, but how far did you say those pine trees were?

Thanks,
Brightnorm</font><hr /></blockquote><font size="2" face="Verdana, Arial">Hi, Brightnorm,

From my usual location for testing, I think the tops of the trees that I use are 150-200 feet away. There's lots of ambient light from streetlights and I'm never very dark-adapted when I do this.

Obviously, the Brinkmann Max Million (1M-CP [not] spotlight--actually 65,000 cd) blows away everything else (except the Vector "banana" 137CO).

I find the pine trees convenient, if not quite far enough, but the big difference I see is the contrast and the ability to see detail (with my distance glasses only, no binoculars) in the needles and coloration at the top. The US, SRTH, the SL6 and the "1M" spots (both Brinkmann and Vector Banana) do this well.

The width of the spot and the evenness of the spot both contribute to the ability to see well. That's where the SRTH really does well. It's peak brightness is about 50% more than the SL6, but the beam is smoother and broader. The US is between the SL6 and the SRTH -- at least the ways I focused it. The beauty of the half-dimpled, half-shiny reflector in the US is that you get a realatively bright corona around the hotspot that gives it advantages for entering a dark room that the SRTH doesn't have. The US can be seen as a simultaneous combination of a 6P and a 9V SRTH. Of course it weighs as much as a 9P and 9P with SRTH combined <smile>.

This flashlight selection business is complex and can't be reduced to a number--but I wish the numbers out there bore some relation to reality. Imagine buying a 12V battery and finding it only delivers 1V! Well, that's about where the Brinkmann 1MCP Max Million spotlight is!

If we had overall lumens and peak candela and polar plots of the light output (candela) and beam shots ALL DONE THE SAME WAY, then I think we could really evaluate lights. BUT, I don't think the marketeers want us evaluating lights on paper. Also, the way each person evaluates the multiple design tradeoffs is significant.

By the way, I dropped my just-turned-off-after-being-on-for-30 minutes E2e from about 4.5 feet onto my concrete garage floor...and the lamp and everything survived fine.

Cheers,

Richard