How to use Tasker to auto-kill app when screen is off?

[Jakobkraft]

I have full version of Tasker which I use to control brightness on certain apps and which I've read does a million other things. I'm pretty sure that there's also a way to auto-kill an app with Tasker so the app switches off automatically when my screen is turned off but I can't figure out how to do it. My phone is rooted T-Mobile Galaxy S2, btw. I know there are certain Task managers that are supposed to be able to do this but I tried several and none of them worked.
The program I'd like to close when screen is off is LGCamera app -- invaluable since I shoot A LOT of HD video (its fixed-focus mode is awesome), but annoying because very often when I reawaken my phone, the camera display is corrupted. Easily fixed if I close and restart the program but could be avoided if the program would just close on its own when the screen goes off.

Any help would be greatly appreciated -- thanks in advance!!

[androiddeveloper1987]

To use a task killer is not a very good idea. Go to this link!
http://androidcommunity.com/forums/f8/to-use-or-not-to-use-task-killers-77261/

[Jakobkraft]

To use a task killer is not a very good idea. Go to this link!
http://androidcommunity.com/forums/f8/to-use-or-not-to-use-task-killers-77261/

Normally I would agree but the fact is when I turn on my screen, if my camera app was open when the screen timed out, the display is completely corrupted and unusable. Go here to see video of the issue: http://androidforums.com/android-applications/455693-lgcamera-app-screen-goes-corrupt-if-screensaver-comes.html
(http://androidforums.com/android-applications/455693-lgcamera-app-screen-goes-corrupt-if-screensaver-comes.html)
In this case, the app does NOT turn off on its own from disuse as that thread you linked suggested, so an app killer is most definitely a 'good idea' in this case.