Nikon D7000 Aperture?

My nikon d7000 isn't changing aperture. I have aperture control in Manual mode, only when i use the eyepiece. When i switch to the live view i lose control over the aperture. Is there a lock on this or something else going on.thanks

Added (1). I'm not sure I'm explaining this well enough… When I'm in Manual mode, I use the eyepiece, I can control the aperture. I then switch to live view because I want to take a video. I spin the aperture wheel and nothing changes?

Added (2). Not an issue on canon's

Have you read the manual? You shouldn't see the aperture change even in manual mode. The aperture will only stop down when you press the shutter release button. You can control aperture straightforward in manual mode (M) and aperture-priority mode (A) using the wheel. In manual mode, you can also use the aperture ring if the lens has it. Just make sure to return the aperture ring to the largest number when going out of manual mode. LiveView shouldn't be an issue. You really have to read the manual.

That's correct because most cameras go to full auto in video. Do some homework sport and crack the book - what a novel idea actually reading the owner's manual. You may learn something.