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-   -   banding under studio lighting at all shutter speeds above 50 (http://www.dvinfo.net/forum/canon-eos-full-frame-hd/474925-banding-under-studio-lighting-all-shutter-speeds-above-50-a.html)

Richard Gooderick March 16th, 2010 03:10 PM

banding under studio lighting at all shutter speeds above 50
 
I was shooting in a photographic studio today. It normally caters for photographers but because I had to shoot some small reflective products it seemed ideal.
It was, except for one thing.
At any shutter speed above 50 I was getting the kind of banding that I have only seen before under street lighting when shooting at 60 (in the UK).
The banding persisted up to 1,000 shutter speed.
It's a problem because I want to film wine pouring from a bottle and to try slowing it down in post.
All the lights were halogen. No fluorescent.
I have a half day in the studio tomorrow to finish off the shoot.
Any ideas anyone as to what is going on and whether it can be rectified?

James Miller March 16th, 2010 03:55 PM

Hi Richard, I take it you are running the latest firmware?

Richard Gooderick March 16th, 2010 04:12 PM

Hi James
I have downloaded it this evening but haven't installed it. I'm halfway through this shoot and thought that it might be safer not to mix framerates.
But I'm converting to 1280 x 720 (using TMPGEnc) anyway so it probably won't matter.
Do you think that upgrading would help? I assume you do you or you wouldn't have asked.

Dan Brockett March 16th, 2010 04:33 PM

When you say banding, do you mean banding in the gradients and or high con areas of the image or do you mean flickering in the picture? From your description, it sounds as if the issue you are describing is flicker.

If it is flicker, assuming you are shooting the UK, assuming you are shooting at 25p, any multiple of 25 should eliminate flicker, 1/25th, 1/50th, 1/100th.

If the issue really is banding, I am at a loss to say what would be causing that any more than normal shooting. The Canon does record 8-bit so you should expect to see some banding and certain situations will exacerbate the banding.

Clarification, please?

Dan

Richard Gooderick March 16th, 2010 05:25 PM

I have probably used the wrong term in that case. It's not what you describe as banding. I didn't realise that is what it is called.
It's not banding as in the areas of the image that change colour but aren't rendered as a smooth gradient.
Its probably flicker. But it appears in bands across the screen. As in noisy horizontal stripes. I normally shoot at 1/60 shutter speed (twice the framerate) but drop down to 1/50 when I see this happening. Usually under street lighting. In this case, in the studio.
I was shooting at 30 frames per second. I have only just downloaded the firmware update this evening and have not installed it yet so I couldn't shoot at 25.
Maybe I should experiment a bit more. My impression was that it was occurring at all speeds above 50 but now I'm not so sure. You have sown the seeds of doubt.
I am in the same studio tomorrow morning and will test the various shutter speeds at greater length.
Not sure whether I should install the firmware update to see if that make a difference.
Thank you for your response. Much appreciated.

James Miller March 16th, 2010 05:50 PM

Richard, install the firmware it will eliminate your problem. The only time you will see it is when you magnify the image (focus assist).

All the best, James

Richard Gooderick March 16th, 2010 05:52 PM

Thanks James
I have just installed it as your post appeared. Thought I may as well. Will report back tomorrow. Many thanks.

James Miller March 16th, 2010 06:10 PM

Hi Richard, excellent. Here is a quick test for you on vimeo.
NTSC at 30 followed by PAL 25 shutter speeds from 50 to 200.
BR, James

Password to view: bulldog

Link:

Yang Wen March 16th, 2010 09:07 PM

I've had the same issue on my 5D2. It had to do with the on-camera LED light I used. It would create banding on the 5D2 but not with my HMC150. I didn't have too much time to do a comprehensive test but I remembered it being not too easily avoidable with that LED light..

I'm sure the latest firmware will not help since it did not address anything specific to this type of issue.

Richard Gooderick March 17th, 2010 01:24 AM

James
Thank you so much for making this clip and putting it up on Vimeo.
The flickering did seem to disappear in the NTSC version at 100.
But it was completely absent in the PAL version.
I can't wait to get into the studio to try it out.
I have downloaded it so that I can show it to the studio owner. He was perplexed.
Many thanks again.

Yang. Thank you. I think that is a question of the different cycle rate of the electricity supply here in the UK interacting with the NTSC framerate. So switching to PAL ie 25 fps with the new firmware upgrade changes that.

Yang Wen March 17th, 2010 07:38 AM

Ahh I just watched the video.. I would describe that as "flickering". "Banding" to me and in my case, was much higher frequency dark bands going horizontally across the image. Probably more than 20 bands fit within the height of the image at any given time.


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