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7D shutter accuracy


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#1 Colin McQuillan

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Posted 13 September 2011 - 12:57 AM

I have the feeling my shutter is inaccurate on my 7D. I'm wondering if this is a common issue, or should I have my 7D body sent in for repair.

The last few times I've shot near fluorescent lights I am getting horizontal banding lines typical of shooting with the wrong shutter speed through my frame even though my shutter is at 60 - dialling the shutter up or down only makes the banding worse. The first few times I saw it I figured it was due to an issue with the ballast of the light fixture or the tube itself.. But I have been seeing the issue far too often for comfort. Also, powering my camera off, then on again at times seemingly softens, or worsens the problem.

Anyone else seeing issues with their 7D shooting @ shutter 60 near tubes?
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#2 Ian Hedley Wakefield

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Posted 13 September 2011 - 06:56 AM

What part of the world are you? Probably the flicker rate of fluro's is 60Hz?

However... Why is your shutter at 1/60? If you're shooting 25fps you should have a shutter of 1/50sec and if you're on 50/60fps shutter should be 1/125sec. For a standard 180 degree shutter.

Hope this fixes your issue.
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#3 Colin McQuillan

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Posted 13 September 2011 - 05:03 PM

What part of the world are you? Probably the flicker rate of fluro's is 60Hz?

However... Why is your shutter at 1/60? If you're shooting 25fps you should have a shutter of 1/50sec and if you're on 50/60fps shutter should be 1/125sec. For a standard 180 degree shutter.

Hope this fixes your issue.


Shutter is at 60 because I am in N. America and shooting in an environment with lots of fluorescent tubes (with 60Hz power running through them.) Any other shutter speed (save a multiple of 60) would create scrolling lines through my footage.

My shutter being at 60 is not the issue here.. My issue is whether or not the shutter speed on the 7D is accurate - as when set to 60, shooting around fluro tubes I am intermittently still seeing lines through my footage.
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#4 Ian Hedley Wakefield

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Posted 14 September 2011 - 04:24 AM

probably cos 30p is actually 29.97p

Try a shutter speed of 1/50 as per this video I found. (about 0.29 sec in)



Hope that helps.

Being down under I haven't come across this before.

All the best.
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#5 Phil Rhodes

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Posted 14 September 2011 - 05:00 AM

I had a situation rather like this back in April when shooting with a 7D under 60Hz HMI light. There was no combination of settings that would completely remove banding; we actually only found this out in the edit when scrubbing through, which makes things a bit more obvious. It wasn't bad enough to wreck the shot, but it wasn't ideal.

P
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#6 Colin McQuillan

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Posted 14 September 2011 - 11:15 PM

probably cos 30p is actually 29.97p

Try a shutter speed of 1/50 as per this video I found. (about 0.29 sec in)

http://vimeo.com/14885028

Hope that helps.

Being down under I haven't come across this before.

All the best.


Hello Ian, Thanks for the replay - Unfortunately frame rate (29.97) is not the issue here. Also - as mentioned in my initial post changing my shutter up or down made the problem worse.

Shutter speed in this case is being used to eliminate horizontal banding caused from flo-tubes running on 60hz power. Regardless of my frame rate (I am actually shooting 24fps, or 23.976 to those who like specifics) - setting my shutter to 60 should eliminate the the scrolling line of flo tubes as it does on all of the various pro cams i shoot with.

The link you shared however is helpful as that guy seems to be experiencing issues similar to mine. It leads me to believe the problem is with the shutter of the 7D being inaccurate. As I haven't heard many rumblings about this from others I also suspect that perhaps it is only an issue with my camera, a certain production/manufacturing cycle of the camera or is an inherent problem with the camera that just hasn't caused others much grief. I did purchase mine after the tsunami mind you..-- traces of radiation fluctuating the electronics? that would be interesting..
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#7 Ian Hedley Wakefield

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Posted 15 September 2011 - 03:29 AM

Sucks. :(

Hope you get it sorted, may be a warranty/service jobbie.

All the best.
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