T3i, Prevent Auto Focus From adjusting exposure in Videos?

[4co2op0]

Hi, First post, searched for an answer but couldnt find what I was needing... I have the Rebel T3i, I have been messing with the video mode and the Auto Focus setting when pressing the shutter half way. The problem I am having, or not enjoying, is when AutoFocus is applied, the videos Exposure is also adjusted. (I am Assuming it changes exposure to get the detail needed to adjust the focus correctly)

What I would like to know is if it is Possible to turn that feature off? I want to use Auto Focus some times, but I do not want the exposure in my final shot to be jumping all over the place. Can this be done?

I have messed with the AE/AF lock features, I tried locking the exposure with the * button, then pressing the shutter button half way for the auto focus, but the exposure still adjusts for a momment during focus.... I am stummped, Please help.

[hsbn]

It's better to put it on manual metering when you shooting video. However, you can try to turn on "back button focus" option. It will take the focus away from your shutter release button.
Canon talks about it here: http://www.learn.usa.canon.com/resources/articles/2011/backbutton_af_article.shtml?categoryId=121
Hope this helps.

[4co2op0]

I have tried changing the button on the back for AE Lock and Shutter Half press options, every setting still ends up adjusting exposure temporarily while auto focus is adjusting. It seems as if it is using it to brighten the scene so it can use the auto focus feature, then it re adjusts back down once in focus. The link you provided I actually had looked at already, but thank you. It does not solve my problem.

Perhaps I can not do what I want it to do, but that just seems silly for canon to have done that, it pretty much destroys the ability to use auto focus, because I do not want the video to be blown out, or darkened, during focus. I can handle the auto focus going way off focus before adjusting to in focus after a few seconds or even just being really slow at adjusting, but I can not handle the image being brightened/darkened whenever attempting auto focus. Any suggestions? Or is it just not possible?