I needed some red LEDs for a night light I'm building, and the ones I had weren't bright enough. I hesitantly bought a pack of 50 (the smallest one) that claimed to emit 100× more light while consuming the same amount of power. Thought it's probably a scam, but the store is reputable and I could probably return them.
Got them today, and while I don't have measurement equipment, I do see that they're like a flashlight while my previous ones are like, um, your ordinary LEDs?
Mind very much blown.
@minoru The luxmeter in N900 has two channels for different wavelengths, not sure if android can export such nuances from your device.
@L29Ah Wow, I didn't think of that! The results are weird though: if it's more than 1cm away from the LED, it gives me 0lux, and any closer than that is 32767lux. Works far better when I aim it at the lamp. I suspect the phone doesn't expect the light to be all red.