user1417: I often shoot indoors for interviews with my D90, but I often get a sort of strobing with it.  Check out the attached picture, to help you see it on a picture, I added red marking, so simply look on the curtain on the right of that.

My best explanation so far was the type of lighting in the room, which is common in most offices, similar that was is in the picture:

Does anybody know what is going on?
Similar experience?
Solution?
Explanation?
Thanks for any input.

user6226: Many types of artificial lighting flicker at twice the rate of the power source. This is most pronounced with fluorescent lighting, but also happens to a lesser extent with incandescent. Common power sources are 50 Hz (in Europe and most of Asia) and 60 Hz (in North America), which cause 100 and 120 pulses of light each second, respectively.
Other than changing the lighting, one has two options for overcoming this problem:
Frame Rates. Choose a frame rate equal to the lighting pulse rate divided by some integer. This is often the simplest option since most corresponding shutter speeds will appear flicker-free.
Shutter Speeds. Choose a shutter speed equal to the lighting pulse rate divided by some integer. This option often isn’t as straightforward, and can constrain one’s ability to control motion blur. On the other hand, this option typically minimizes flicker under a broader range of lighting and power types.
For example, in North America, the standard 24 and 30 fps settings work with most shutter speeds (since 30×4 and 24×5 = 120). Use the tool below to find other flicker-free shutter speed and frame rate combinations:
http://www.red.com/learn/red-101/flicker-free-video-tutorial

user-1: You seem to be on the right tracks, fluorescent tubes are notorious for flickering and CMOS sensor is read row-by-row in video mode. 
Try shooting under window light and/or use your own lighting, e.g. a LED video light. Try shooting so there's not much office visible in background, you won't be able to light it all.

1417: <p>I often shoot indoors for interviews with my D90, but I often get a sort of strobing with it.  Check out the attached picture, to help you see it on a picture, I added red marking, so simply look on the curtain on the right of that.</p>

<p><img src="https://i.stack.imgur.com/dcXrt.jpg" alt="strobing effect when filming with D()"></p>

<p>My best explanation so far was the type of lighting in the room, which is common in most offices, similar that was is in the picture:</p>

<p><img src="https://i.stack.imgur.com/nJNrE.jpg" alt="Office lighting"></p>

<p>Does anybody know what is going on?
Similar experience?
Solution?
Explanation?</p>

<p>Thanks for any input.</p>
 6226: <p>Many types of artificial lighting flicker at twice the rate of the power source. This is most pronounced with fluorescent lighting, but also happens to a lesser extent with incandescent. Common power sources are 50 Hz (in Europe and most of Asia) and 60 Hz (in North America), which cause 100 and 120 pulses of light each second, respectively.</p>

<p>Other than changing the lighting, one has two options for overcoming this problem:</p>

<p>Frame Rates. Choose a frame rate equal to the lighting pulse rate divided by some integer. This is often the simplest option since most corresponding shutter speeds will appear flicker-free.</p>

<p>Shutter Speeds. Choose a shutter speed equal to the lighting pulse rate divided by some integer. This option often isn’t as straightforward, and can constrain one’s ability to control motion blur. On the other hand, this option typically minimizes flicker under a broader range of lighting and power types.</p>

<p>For example, in North America, the standard 24 and 30 fps settings work with most shutter speeds (since 30×4 and 24×5 = 120). Use the tool below to find other flicker-free shutter speed and frame rate combinations:</p>

<p><a href="http://www.red.com/learn/red-101/flicker-free-video-tutorial" rel="nofollow">http://www.red.com/learn/red-101/flicker-free-video-tutorial</a></p>
 -1: <p>You seem to be on the right tracks, fluorescent tubes are <a href="https://photo.stackexchange.com/questions/4115/do-fluorescent-lighting-and-shutter-speed-create-a-problem-with-color-cast">notorious</a> for flickering and CMOS sensor is read row-by-row in video mode. </p>

<p>Try shooting under window light and/or use your own lighting, e.g. a LED video light. Try shooting so there's not much office visible in background, you won't be able to light it all.</p>
