Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines

Spiros Zaharakis · March 28th, 2011, 12:03 AM

I'm quite surprised at the comments about the colors and exposure on this video though.

On my photo editing (calibrated) monitor it looks like the red channel is overexposed and whites look washed out in some shots (00:23, 00:55, 02:08 and a few more).
Wouldn't it be better if instead of increasing the red channel you were further lowering the blue and green channels?

Philip Lipetz · March 28th, 2011, 02:45 AM

In my previous review I stated that the green channel was too strong in low light. So why did I not change it here? Partially an experiment, and partially because I was on a portable computer, and more simply because decreasing blue and green did not give pleasing skin tones with the auto WB I used as an experiment. No WB on cards. The auto WB failed but was at least consistent from shot to shot.

The white is definitely blown out in some shots. On the monitor it indicated that they would be. Exposed for dark skin. Is this a DR range limit of the camera? In the previous review I stated that in low light the DR is much less. I have to experiment with different gamma curves for low light. Brian Weed in his Vimeo forum has posted some gamma curves for low light XF300 work.

Pat Reddy · March 28th, 2011, 06:58 AM

Spiros,

I don't know enough about it to explain it, but a monitor calibrated for photo editing will not be calibrated for video. It has something to do with differences between how color is handled in video versus still photography. This may have some bearing on what you are seeing.

Pat

Spiros Zaharakis · March 28th, 2011, 07:51 AM

Pat, I am aware of the differencies (not the tech behind them though) but to my understanding in this case the effect would have being even more pronounced on a broadcast monitor.
It has to do with the diffeence between photo white/black levels and video white/black levels.

Every time I have to remember not to make the footage pleasing to the eye or it will have blown out whites and blocked shaddows on the DVD.

I wish I knew more about video color grading and broadcast colors but I hate to go through one more learning curve.

Pat Reddy · March 28th, 2011, 08:43 AM

Thanks for the clarification Spiros. You know more about it than I do. :)

Pat

Pat Reddy · April 1st, 2011, 07:49 PM

Thanks Philip for your analysis and video. These were instrumental in convincing me to order the camera.

Pat

March 28th, 2011, 12:03 AM	#16
Spiros Zaharakis Regular Crew Join Date: Mar 2008 Location: Chania Crete Greece Posts: 171	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines I'm quite surprised at the comments about the colors and exposure on this video though. On my photo editing (calibrated) monitor it looks like the red channel is overexposed and whites look washed out in some shots (00:23, 00:55, 02:08 and a few more). Wouldn't it be better if instead of increasing the red channel you were further lowering the blue and green channels?

March 28th, 2011, 02:45 AM	#17
Philip Lipetz Major Player Join Date: Jan 2011 Location: Columbus, Ohio Posts: 273	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines In my previous review I stated that the green channel was too strong in low light. So why did I not change it here? Partially an experiment, and partially because I was on a portable computer, and more simply because decreasing blue and green did not give pleasing skin tones with the auto WB I used as an experiment. No WB on cards. The auto WB failed but was at least consistent from shot to shot. The white is definitely blown out in some shots. On the monitor it indicated that they would be. Exposed for dark skin. Is this a DR range limit of the camera? In the previous review I stated that in low light the DR is much less. I have to experiment with different gamma curves for low light. Brian Weed in his Vimeo forum has posted some gamma curves for low light XF300 work.

March 28th, 2011, 06:58 AM	#18
Pat Reddy Major Player Join Date: May 2006 Location: Colorado Posts: 288	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines Spiros, I don't know enough about it to explain it, but a monitor calibrated for photo editing will not be calibrated for video. It has something to do with differences between how color is handled in video versus still photography. This may have some bearing on what you are seeing. Pat

March 28th, 2011, 07:51 AM	#19
Spiros Zaharakis Regular Crew Join Date: Mar 2008 Location: Chania Crete Greece Posts: 171	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines Pat, I am aware of the differencies (not the tech behind them though) but to my understanding in this case the effect would have being even more pronounced on a broadcast monitor. It has to do with the diffeence between photo white/black levels and video white/black levels. Every time I have to remember not to make the footage pleasing to the eye or it will have blown out whites and blocked shaddows on the DVD. I wish I knew more about video color grading and broadcast colors but I hate to go through one more learning curve.

March 28th, 2011, 08:43 AM	#20
Pat Reddy Major Player Join Date: May 2006 Location: Colorado Posts: 288	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines Thanks for the clarification Spiros. You know more about it than I do. :) Pat

April 1st, 2011, 07:49 PM	#21
Pat Reddy Major Player Join Date: May 2006 Location: Colorado Posts: 288	Re: Low Light Canon XF100 XF105 Test - 4:2:2 Codec Shines Thanks Philip for your analysis and video. These were instrumental in convincing me to order the camera. Pat