5D mark iii video issue..

[GoodVendettaPhotography]

I bought the canon 5d mark iii just under two months ago from best buy. I bought this camera for photography; however, I went to a concert last night and shot some film...when I got back and opened the file on my Mac, there were faint, big black lines that continuously move up the screen from bottom to top...? Any ideas on why this might be occurring. It sucks because I think I've breached the return day limit at best buy :-/

Thank you

[paul13walnut5]

Were there video screens or a large led display behind the act?   Sounds to me like a clearscan issue, where the camera is out of phase with powered source of light.  This happens most often with computer or tv displays, but can also happen with certain type of lights.  Traditional video cameras above a certain level typically have a clearscan mode so you can change the hz of the electronic shutter.  On a 5d3 you have limited options.  Especially in a concert situation.  Running the camera off mains at the same phase is one fix where practical, sometimes juggling the shutter can help.  Post a clip, but it doesn't sound like a fault.

[GoodVendettaPhotography]

No, everything was dark expect for some lights on the performer. I used the 50 1.2....I'll have to post it up once I get home tonight.

[cinema-dslr]

do you remember how fast your shutter was?
anything faster than 60 can give problems

[GoodVendettaPhotography]

Hmm, I don't, that's a good point though..I was switching from pic to video in manual mode so there's a very good chance the shutter was around 100 at f1.2...

[Hydrosmerc]

Oh jeez I can't believe i made an account just to answer this.

Anyway, your camera is perfectly fine.
It's a problem with florescent lighting vs the progressive scan on the CMOS of the camera.

Just take your camera and shoot some video now and you'll see that it's gone.

Cheers!

[GoodVendettaPhotography]

Hope you're right  thanks, I'll try something else later tonight, hopefully.

[atrocious]

Yeah, you will have that at shutter speeds faster than 50 or so. I generally keep it at 30 when shooting video. You wouldn't have this problem in natural lighting but the frequency of the artificial lighting will cause those scanning bands in the video mode.

[cinema-dslr]

for video the best shutter speed is double the framerate here in pal country it's 25fps so a shutterspeed of 50 is ideaal for smooth motion.
Higher shutterspeeds will give you choppier motion (even in natural light) so only good for very fast moving subjects
also it will give you strobe effect with a lot of lighting sourches and when shooting video walls etc...

you can get away with lower speeds but motion will become more blury/soft.

[GoodVendettaPhotography]

Okay, thanks guys! I had no idea! 

[Axilrod]

Certain types of lights can also introduce those scan lines even if you are using the right shutter speed.  I've seen it happen here and there with christmas lights in dark situations.