Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Question sums it up. In the interests of keeping this reasonable, I already acknowledge the lasgun-flashlight meme, this is about the lowest power on a lasgun seen in the fluff.

Laser pointer?

I know highest is penetrating the weaker points of power armour..

But that's something like 25% of magazine per shot or even higher, maybe 2 shots a magazine.

Lowest is enough to cause a serious blister and some heat damage, but nonlethal.
Source: First And Only

But only on las guns with variable power setting capability. I don't think they have that.

The lowest setting is heresy, the others are deliverance and purify!

In the tabletop game, Dark Heresy, you basically have three options for Lasguns/Laspistols: You can fire it normally, (Giving a shot that's marginally weaker than an Autogun/Autopistol,) you can overcharge it (Doubling the charge consumption, but increasing the damage and AP by 1, making it slightly stronger than an Autogun/Pistol,) or you can double overcharge it (quadrupling ammo consumption, but increasing damage and AP by 2, making it fairly formidable.)
(For reference, most guns deal damage in the d10+3 range, but it is then reduced by 3-4 points of Toughness and 3-4 points of Armor, against people who generally have 10-12 wounds. Usually, you need to roll something between 4-6 in order to cause damage, and that's only going to chip away a few wounds.
So adding effectively 2 or 4 points of damage usually amounts to a pretty hefty increase in damage dealt, making even the weakest roll capable of hurting most characters, and making better rolls go from 'A bit of damage' to 'You just killed a guy'.)
(There's also a 'Hot-shot charge pack' which increases the damage by a huge amount (+2 damage, +4 to armor pen, and you get to roll two dice and pick the highest for the d10, which is awesome,) but it's one-use before you have to recharge it.)

In short, the settings don't seem to actually go very low, which makes sense - It's a heat gun, not an electricity gun, so whereas a Star Trek phaser might conceivably be able to 'Stun' someone, a low-powered Lasgun is just going to warp the paint on their armor. It's a gun designed for killing people, not restraining them.