Phil Hoppes
October 30th, 2008, 09:33 AM
I hope this is the right forum for this question, was not sure if it should be in Photons, DVX100, or what ever but I'll get to my question and see where it goes.
I've got a new DVX100b. Nice camera. I've hooked it up to my MBP which is running CS4 with the new Apple version of OnLocation. I was focusing on a standard Gretag Still Camera color chart (4x6 color boxes) and noticed a number of things, first off in the Y Waveform display their seems to be a crowning of the waveform, ie, recorded intensity appears to peak in the center and taper off at the edges. I'm not sure if this is simply an artifact of the camera or possibly the setup. I've not changed a thing on the camera relative to setup so it is as it came from the factory. This surprised me as my expectation would be that it should be fairly flat across the field. I changed my illumination to put the camera in a dark room with a single flat, diffused light source from behind the camera and I still see the crowning. This lead me to my real question which centers on camera calibration in general. To this, what are the best chart, charts to use in camera calibration and is there a good reference book or on line source to teach me how to use these charts? I found a web site on charts:
Accu-Chart.com - Vertex Video - Camera Calibration Charts (http://www.accu-chart.com/calibration_charts.asp)
Are these the best charts? Are there others I should use?
And a few good articles on Ken Stones web page:
Video Levels in Final Cut Pro (http://www.kenstone.net/fcp_homepage/video_levels_nattress.html)
Chroma Sampling: An Investigation (http://www.nattress.com/Chroma_Investigation/chromasampling.htm)
While these are both excellent articles what I'm looking for is a tutorial of sorts that explains the chart, the test, what to adjust and why I'm doing it. Not looking for a tutorial here, I can do the reading, just looking for a few good links or books that I should get to help me out.
Tnx,
I've got a new DVX100b. Nice camera. I've hooked it up to my MBP which is running CS4 with the new Apple version of OnLocation. I was focusing on a standard Gretag Still Camera color chart (4x6 color boxes) and noticed a number of things, first off in the Y Waveform display their seems to be a crowning of the waveform, ie, recorded intensity appears to peak in the center and taper off at the edges. I'm not sure if this is simply an artifact of the camera or possibly the setup. I've not changed a thing on the camera relative to setup so it is as it came from the factory. This surprised me as my expectation would be that it should be fairly flat across the field. I changed my illumination to put the camera in a dark room with a single flat, diffused light source from behind the camera and I still see the crowning. This lead me to my real question which centers on camera calibration in general. To this, what are the best chart, charts to use in camera calibration and is there a good reference book or on line source to teach me how to use these charts? I found a web site on charts:
Accu-Chart.com - Vertex Video - Camera Calibration Charts (http://www.accu-chart.com/calibration_charts.asp)
Are these the best charts? Are there others I should use?
And a few good articles on Ken Stones web page:
Video Levels in Final Cut Pro (http://www.kenstone.net/fcp_homepage/video_levels_nattress.html)
Chroma Sampling: An Investigation (http://www.nattress.com/Chroma_Investigation/chromasampling.htm)
While these are both excellent articles what I'm looking for is a tutorial of sorts that explains the chart, the test, what to adjust and why I'm doing it. Not looking for a tutorial here, I can do the reading, just looking for a few good links or books that I should get to help me out.
Tnx,