For those experiencing input lag on the PS3 version of Battlefield 3, Senior Gameplay Designer, Alan Kertz, might have a suggestion or two.

Kertz recently stated that “if you are experiencing PS3 input lag, please check that your TV is in game mode. We have just fixed a laggy PS3 by enabling game mode.” Furthermore, as an example, he explained that “for Samsung TVs Game Mode can be turned On in the General Settings.” He added “we reproduced the lag on a Samsung TV and then eliminated it by adjusting TV settings without changing the game. That’s a fix.”

As another option, “if your TV does not have Game Mode, some users are suggesting PC mode works nicely for their TV,” mentioned Kertz. This seems to be the case for LG TVs specifically. “For LG TVs, press input then blue button, PC mode works better than game mode.”

Additionally, Kertz mentioned to one PS3 user, “I think the latest update added an option to disable vsync. Turning it off can improve responsiveness.” Upon contacting Kertz for further information, he clarified that this option “is under Video in the Options Menu on PS3.” Lastly, “you may also try disabling AA in the BF3 options menu, some users report that improves performance.
Also try this fix from @xKidera: After changing to a higher sensitivity and back to original, lag decreases PS3 BF3 Input lag 2 - YouTube
Un alt fix

You may also try disabling AA in the BF3 options menu, some users report that improves performance.