I just ordered 3 of these lights this week and a few gel sheets. The 1/2 minus green, a 1/4 minus green and a ND-gel. I hear they where bright ;)
I was actually looking for a LPmicro, but this is a really good deal. A shame i couldn't find them in europe, now i have to pay a lot for shipping. They should arrive in a few days.

My previous post was clumsily worded, my apologies!

Thanks for understanding, Chris, and thanks for the explanation.

Not any more... they're now apparently quoting $79 !!!!

So, either their production costs have gone up to double what they were or they're raking in a hefty profit!

I found them on ebay and amazon for $34, at b and h for $49 one minute ago.

Got mine from eBay as well. Even with postage to the UK they're still a bargain. Listed as Sima and not Sigma as the title of this thread uses.

Reduction in the intensity of lights
 

I got two lights from VideGuys for $29 each. They work great for 15 minutes and then the intensity of the light comes down a good bit. Is that normal with these lights?

I DO know that as the battery voltage drops, the light output WILL change. What I do not know is whether a LED's lumen output is linear to voltage or not, but I have not observed a sudden drop, but have observed a gradual one. I find that the rechargeables have a definite rebound effect, so turn them off between takes... even one showing some dimunition in light output will recover enough for a brief spell at full brightness if given 5 minutes to recover... but to answer you directly, I am not sure I have left them on full long enough to oberve your situation. I'll have to try it.

Thanks Chris for the info..

Mine arrived from the US. It comes with a 110v charger rather than a 240v/110v version. Luckily it's 5v and I had a compatible UK version in my box of bits.

Nice little light, for the money it's hard to beat.

Mine arrived too, yesterday. I also didn't think about the US-charger, so i had to spend some money for an adapter. So, after 4 hours charging i turned the first one on facing my eye's... Man that hurt :)
Luckily the gels had arrived too, i didn't have the time for testing, but i think the 1/4 minus green gel is almost perfect too remove the very slight green tint.

I like the fact that the lights weights almost nothing. Any 4xAA or accu light will be really heavy compared to this one.

How did you get them for $29 each, as videoguys has the Sima light for sale for $39.95 each?

Oddly, I have bought these lights from VideoGuys three times and everytime the item page says $39.95 and when I put them in the basket the checkout page goes to $29.95. Maybe they're on sale or it's a mistake, but they honor the price.

Nice little lights, we issue them with video kits the reporters take and bought some for the Canon S5is cameras that some others use. They are a little spotty, but some frost acetate and a little tape improves the quality of the light somewhat, although for quick interviews in dark places nobody bothers... I just wish they took interchangable batteries..../Battle Vaughan /miamiherald.com video team

I ran a test to see how long these lasted, just turn on and run, I didn't notice a drop off over the 45-50 minute run time, but then again I wasn't watching for it... looked about the same to me the whole time. Great little lights for the $, I paid around $35 @, shipped from an eBay seller. I've been fiddling around with a diffuser, as they are bright enough that it's probably a good idea to make it easier on the subjects's eyes.

You could buy ten of these for less money than one commercially available leds. The only drawback that I can see is that you can't run them on the power supply. I imagine a little investigation and a switch could remedy that.

That's what happened for me too. At the checkout it showed up as $29