True in this case the current limiting resistor is built in, that is why I said there were exceptions, this one is such an exception.
Not everyone who reads posts like this will realise that, and later might remember someone talking about powering a LED from just a voltage source, and make the wrong conclusion that that is fine to do so! So its advisable to once again explain that any LED needs a current limiting device, so that they will not try to just power a LED without thinking about the need for current limitation. Time and time again I see people making such a mistake, often with dire consequences.
but yes, in this case the "3W 850nm LED" has it built in..... I post edited my previous post somewhat to make this more clear.
By the way it is typical for resellers like this that they don't even mention on which voltage this device is intended to operate, but like I said it cannot be intended to be operated from the 3.3Volt supply, as for a 3W device it would indeed draw almost an ampere from the 3.3V supply.
Its also unlikely that it is using a single LED, if it really is drawing 3Watts, more likely its a 5V powered device that has two 2Volt LED's in series, so that the current regulator only has to dissipate 1Volt. That my best guess, but who knows with products like this that come with no technical info at all....
On second thought, I can see that these LED's are meant to be directly screwed to a raspberry PI camera board, so in that case the voltage and polarity is fixed anyway. Problem with that is that AFAIK raspberry PI cams do not have any voltages on the four mounting holes this LED is supposed to be mounted to, so you probably have to also buy an aftermarket camera with it, and I have seen two of these LED's mounted on either side of what seems to be a fake cam, meaning they power it with 2A and 3V3, (the only power voltage available on the camera module) which is ridiculous as 2A cannot be supplied by any PI on the 3V3 line, and besides 2A through the single 3V3 pin of the FPC camera cable would fry the connector, so these cannot ever be 3W LED's, the plot thickens.