Video: How do I maintain the same brightness when zooming with a kit lens?

[ROFLT2i]

I need to film a comedy video in the style of a single-camera sitcom with lots of zooming in and out (a la "Parks & Rec" and "The Office"). But when I zoom using the 18-55mm kit lens that came with my Canon t2i, the brightness changes in LiveView. It gets brighter as I zoom out, and darker as I zoom in. How do I maintain the same level of brightness when zooming?

[dlrpgmsvc]

You must buy a constant aperture zoom lens... very expensive! ;-)

[crazyrunner33]

I agree with the above.  The closest you can get to avoiding the exposure change is by zooming out all the way and setting your aperture to F5.6 or slower, but even then I still notice some exposure changes.

[1%]

Kit lens is f-3.5 to 5.6 so above 5.6 shouldn't be any changes.

[ItsMeLenny]

or shoot in complete auto video

[g3gg0]

without touching aperture, zooming will cause less light being projected to a sensel.

like when you hold a single lens into the sun and move it forth and back.
when all light is bundled to a small spot on the concrete, its the brightest.
same applies to lenses in camera.

[Ervz]

1% is correct. Simply stay 5.6 or higher, and make sure you're in Manual mode. Enjoy!

[dlrpgmsvc]

Wrong! Kit lenses are digitally controlled in steps for aperture values. So you will end up in jumpy light intensities while zooming! Sorry but this is the hard reality...