shifting colors at dusk at DVinfo.net

Brent Hamilton · September 22nd, 2007, 12:51 AM

Occasionally when shooting my son's football games I can see a color shift toward a reddish hue, then shift back to to a balanced color. Tonight it occurred at dusk under stadium lighting. I was shooting in manual mode at 1/120 to 1/150 shutter speed, f3.0. Custom WB set using lastolite.

I have observed this during previous practice sessions when the shutter speed was too fast.

Anybody have any ideas as to what is going on?

Erik Norgaard · September 22nd, 2007, 02:54 AM

Quote:

Originally Posted by Brent Hamilton

Occasionally when shooting my son's football games I can see a color shift toward a reddish hue, then shift back to to a balanced color. Tonight it occurred at dusk under stadium lighting. I was shooting in manual mode at 1/120 to 1/150 shutter speed, f3.0. Custom WB set using lastolite.

I have observed this during previous practice sessions when the shutter speed was too fast.

Anybody have any ideas as to what is going on?

I think you can find a number of threads on this or similar issues. Take a look at the "No Magenta" preset, it should address that problem.

Cheers, Erik

Don Palomaki · September 22nd, 2007, 06:02 AM

Do you see this at 1/120, or just at 1/150 and faster shutter? Do you see it ata 1/60 shutter?

If only at 1/150 and faster shutter, it is probably caused by the slight variation in output color of the stadium lights over the power frequency half-cycle, and the fact that the camcorder field rate is not exactly at line frequency. Keeping the shutter at 1/120 or 1/60 would be a solution.

Brent Hamilton · September 22nd, 2007, 08:36 AM

It happens at 1/150 and faster for sure. I've also noted at some stadiums 1/150 or 1/120 shows no phasing. I guess the next time this occurs I'll keep lowering the shutter speed until the phasing disappears. However for shooting football games I probably should not go lower than 1/100...correct?

Don Palomaki · September 22nd, 2007, 05:44 PM

Faster shutter allows better freezing of action within a video field, so you have less motion blur in field captures, and perhaps more distinct interlace artifacts in frame grabs. However, faster shutter can also yield a bit more strobe-like feel to video.

Slower shutter will give video a more smooth/fluid look thanks to the motion blur that makes the visual transition from field to field not as sharp. Which is better depends on which look you prefer. Also the slower shutter may allow smaller aperture for better depth of field, if that is an issue, or perhaps a biit less gain for a cleaner image.

Whether or not it is an issue at a field will depend on the type lighting used. Discharge lamps are more prone to this effect, but if 3-phase lighting is used on each light pole, it will not be as pronounced.

Brent Hamilton · September 23rd, 2007, 06:50 PM

Thank you for the information.

September 22nd, 2007, 12:51 AM	#1
Brent Hamilton Regular Crew Join Date: Aug 2007 Location: Oklahoma City, OK Posts: 30	shifting colors at dusk Occasionally when shooting my son's football games I can see a color shift toward a reddish hue, then shift back to to a balanced color. Tonight it occurred at dusk under stadium lighting. I was shooting in manual mode at 1/120 to 1/150 shutter speed, f3.0. Custom WB set using lastolite. I have observed this during previous practice sessions when the shutter speed was too fast. Anybody have any ideas as to what is going on?

September 22nd, 2007, 06:02 AM	#3
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Do you see this at 1/120, or just at 1/150 and faster shutter? Do you see it ata 1/60 shutter? If only at 1/150 and faster shutter, it is probably caused by the slight variation in output color of the stadium lights over the power frequency half-cycle, and the fact that the camcorder field rate is not exactly at line frequency. Keeping the shutter at 1/120 or 1/60 would be a solution. __________________ dpalomaki@dspalomaki.com

September 22nd, 2007, 05:44 PM	#5
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Faster shutter allows better freezing of action within a video field, so you have less motion blur in field captures, and perhaps more distinct interlace artifacts in frame grabs. However, faster shutter can also yield a bit more strobe-like feel to video. Slower shutter will give video a more smooth/fluid look thanks to the motion blur that makes the visual transition from field to field not as sharp. Which is better depends on which look you prefer. Also the slower shutter may allow smaller aperture for better depth of field, if that is an issue, or perhaps a biit less gain for a cleaner image. Whether or not it is an issue at a field will depend on the type lighting used. Discharge lamps are more prone to this effect, but if 3-phase lighting is used on each light pole, it will not be as pronounced. __________________ dpalomaki@dspalomaki.com

September 22nd, 2007, 08:36 AM	#4
Brent Hamilton Regular Crew Join Date: Aug 2007 Location: Oklahoma City, OK Posts: 30	It happens at 1/150 and faster for sure. I've also noted at some stadiums 1/150 or 1/120 shows no phasing. I guess the next time this occurs I'll keep lowering the shutter speed until the phasing disappears. However for shooting football games I probably should not go lower than 1/100...correct?

September 23rd, 2007, 06:50 PM	#6
Brent Hamilton Regular Crew Join Date: Aug 2007 Location: Oklahoma City, OK Posts: 30	Thank you for the information.