Weird "Uneven White Balance" across the frame....

[scott_turner2]

<p>Hi all, strange thing happened here today with my XT1. I've noticed recently that in certain fluorescent light, there is a flicker in the viewfinder like when you take video of a TV screen and the frame rates don't match. Strangely, it never showed up in the pictures until today. I'm guessing that there is some kind of frequency thing with the viewfinder that causes this.<br>

Anyway, it looks to me like an uneven white balance across the frame, that shows up as a huge orange band across the picture. Even weirder, it only happens with my 35mm f/1.4 lens. When I put my 18-55 on and took the same shot at 35mm, the problem went away. Even weirder still, I can't get it to repeat consistently. The camera is under warranty still, so I'm not terribly worried. But still, this is a little weird. I've attached a photo below, anyone ever seen anything like this before?</p><div></div>

[scott_turner2]

<p>Nevermind. Did some further googling with a different set of key words. Appears to be an issue with the lights, not the camera. Thanks!</p>

<p>Scott</p>

[Ed_Ingold]

<p>Fluorescent lights flicker at 120 Hz (both sides of the 60 Hz current). Different phosphors have different persistence times. CMOS sensors sample cells one row at a time across the width, creating a rolling shutter effect. There are a things to watch for when using fluorescent lamps.</p>

<p>In the past, I've had trouble shooting video under fluorescent lights. I noticed periodic change in exposure when spooling through the files at high speed. It is due to an aliasing effect between the AC frequency and the usual 30 fps video rate. I learned to keep the shutter speed low (or shutter angle, in moviespeak), typically 1/60 sec (180 degrees). Auto exposure in newer cameras is able to offset the "beat frequency" almost perfectly.</p>

[Sanford]

<p>I've seen something similar to that when using the Velvia mode. The color is so strong and the contrast so high that yellow or whatever will turn to white across the scene with the slightest change in light intensity.</p>

[sebastianmoran]

<p>Some LEDs flicker as well. </p>