The Sceptre - PScal's quest for a superthrower

Excellent aspheric build, I will have to add it to the list of most power flashlights over 1Mcd :slight_smile:

Very nice build!

Nice work on the upgrade. :+1:

Very impressive light! So, are you happy with the new emitter? Higher beam intensity but a smaller beam size.

I think your measurement is high (relative to other peoples’ measurements) not because of your lux meter but because of the method you used to calculate the candela. While the method does make some sense, I’m not sure it is correct. See this thread for discussion: The proper way of calculating lux / cd / candlepower

Thanks for the info about measuring lux. I’ll read up on that. I do like the new emitter. This light is all about lux, so the smaller but more intense beam is perfect. I also like the lower power consumption / heat output and longer battery life that this LED offers.

Yeah I agree, see this post specifically: The proper way of calculating lux / cd / candlepower - #35 by EasyB
I made that thread to explain the concept that I read about on CPF, but after some further research it seems to be incorrect.

The light coming out of a lens is not a single cone of light that diverges from one point, it is an infinite amount of light cones coming from the surface of the lens.
See image 5: Light collimation with an LED flashlight
Based on this, the total lux of the flashlight is simply the sum of all these cones of light.
Since each cone behaves according to 1/d^2, then the sum of all cones also behaves proportional to 1/d^2

So in fact the light converges at the lens, not behind it.

Very nice! I like that you can actually see the shape of the LEDs package in the beam. 1.77Mcd is great!

You could probably still optimize it a bit though. With 75mm lens diameter with no ar-coating and this LED it should be possible to get up to 2.8Mcd with a 315cd/mm^2 LED and perfect placement of the collar. The collar can increase the luminance of an XP-G2 LED by up to 120%. This effect might actually be greater with an even smaller LED.

I would think about modifiying the light so you can use the more high-quality lens. It should make a difference with such a tiny LED because of its more accurate shape.

I wish those wavien collars were more readily available. Pretty sweet build you got there

The initial lux readings are probably inaccurate. I will work on getting better long distance readings.

Due to the easy access I designed into the light, it is definitely possible to spend time optimizing focus of the collar. I will spend more time on that and rig a lux meter to give me real time info while focusing.

The optolife lens was a disappointment. I will take photos to show the difference. That should explain everything. At this point I plan to stick with the dx lens. Lenses get so expensive so fast. Also, part of what I enjoy about this light is the beauty of the elephant host. I don’t want to change the looks to fit a different lens.

Also, keep in mind that I am not driving the LED at 2.5 amps. With 6x 7135 chips, the LED sees 2.28 2.1 amps. I may upgrade the driver at a later time, but I am very close to the top of the curve and diminishing returns are in effect.

Thanks to everyone for the encouraging words and tips on furthering the performance of this light.

I spent some time with the lux meter and the wavien collar. I observed something unexpected due to the asymmetrical shape of the LED. I get the highest lux reading when the rectangle is perfectly centered over the rectangle. However, the die is not in perfect orientation over itself. My thoughts are that I should focus on the die itself and not the entire package / highest lux reading. I’d like to hear others’ thoughts, too. As an experiment, I can glue the collar in place both ways and take measurements, but my free time is a bit limited and I think some discussion could be interesting.

I also realized that my batteries were almost dead, so I charged them up. That should help a bit with lux. :person_facepalming: I’m going to officially scratch the initial lux readings until things are worked out.

Here are photos to illustrate the difference between the Optolife and the DX lens. The optolife lens scatters light. These photos are taken with the same camera settings, stepped down so as not to overexpose. In person, the scattering is much more pronounced.



Wow that is bad.
My optolife lenses had almost none.
What is the product code of the one you bought?
Are you sure it was plano-aspherical?


Ok well that’s unfortunate.
Must be a defective one, or it’s bad because of how low the F number is.
My A380 an A037 are higher F.

I would recommend this one for people who are looking for a precision 75mm lens, it’s pretty cheap:

Excellent build.

The Sceptre is not performing as I hoped it would. Even with fresh batteries, the lux meter gives me lower readings than my GT and from the previous iteration of the light. I suspect the LED may have been damaged or not like being overdriven. I am considering swapping back the “king” xp-g2 or installing a flat black LED. The quest for throw continues!

My guess it that the lens isn’t precise enough. You can check this by looking at the light from far away. The entire lens should be yellow (or lit up when turned on).

I may have to get my wallet out again. I should amend my last post to say: The quest to “throw” money at the problem continues! :money_mouth_face:

That Edmund lens has an even shorter focal length than the Optolife.

You should calculate if this lens actually makes sense with the emission angle of the Wavien collar. If the focal length is too short th lens wont be used completely which leads to less throw.

I think this is the lens used in the Mjölnir from Vinz.

Absolutely. The dx lens is right at the sweet spot for focal length and the collar.