Actually its a problem with a psyker in my group using Distort Vision in a highly creative fashion.

I have read the rules on the psychic power and I have seen his "interpretation" of the rules and they do kind of make sense. However it is sucking the fun out of the game for the other players, who have come to me and asked me, as the GM to do something. I have suggested I will look into it, but that they should also ask him to let them do something.

Here is the scenario;

The group infiltrate a known heretic building, and come across an open door. By casting distort vision, this player can go look inside the room, then come back out. He can theoretically press any buttons he likes and do whatever else he wants in this free turn, as the power is free to cast. Also he uses his distorted vision to move around and pretend to be him, distracting enemies etc. I can see no rule allowing this in the book, but it also doesn't say this is not possible.

The other players are getting a little perplexed as to how this low level minor power is so good, and I am having trouble myself with explaining this, but it doesn't appear to be against the rules.

Any thoughts? Anyone else come across such interpretations, and if so how did they deal with them? I don't want to penalise good ideas, but at the same time, every encounter starts with him going invisible, and hiding, or running behind someone to unleash some point blank range death with a shotgun or similar item next turn.

If I understand it correctly the image of him will still have to follow his actual actions, and stay within 10 meters of him at all times. He also reappears every turn in his actual location since the power is not sustainable. The NPC's can easily catch on after a while. Also distort vision only effects vision based sensory. So Psyniscience, Smell, Touch, Auditory, and taste still work fine. Have a few npc's charging at the image accidentally run into the actual character, or pressure sensitive plates in the floor set off alarms when the image is walking on something else entirely. Or throw in a random psyker to oppose him. He'll be too busy directing his efforts at the psyker to mess with your other npcs.

Distort Vision was never intended to function in that fashion - it has been altered to far closer to what it was intended to be in the Dark Heresy Erata 2.0 doc. The changes are "official" from FFG's point of view.

They're also official from my point of view, for what it's worth. I think his use of the original power is very clever though - I could see a write up of such a Discipline Power with a far higher Threshold.

I had no problems with it being used as it was, but the other 5 players were getting annoyed at him being able to solve pretty much everything on a really low casting value, meaning other stealthy characters were effectively outgunned in their chosen field by a psyker who could also shoot lightning and do various other things.

It was a sore point where an assassin with blind fighting still could not find this guy, even with the best quality bionic eyes as these too were apparantly fooled. I think the ammended version makes a lot more sense.

I have the errata, I just had not noticed that this particular power had been changed. I guess I need to take a better look at the errata!

Thanks for confirming this, I will go through the errata more thoroughly before the next session and inform the group of these changes.

Yeah the Errata 2.0 is pretty much the munchkin psyker's worst enemy.

But I don't think Distort vision would allow the psyker to see anything through the eyes of the image he created. I play a pysker and under the old rules I could project my image inside a room but never gain sight from what the image sees...

It was the invisible self that did lots of mischief. The image just jumped around waving hands, to distract bullets towards him, or various other silly acts.