Quote:
Originally Posted by old_tv_nut
Pete - Some things you could try: you could set your camera for a slower shutter (like 1/8 or slower). Also, you can check if the green appears this dark and the cyan this light to the eye. Also, you could check the relative gain of I and Q.
If you look at the R, G, and B outputs with a scope, you can check for waveforms that are nice and flat and equal-height sqiare waves.
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Clearly I have not mastered the new camera, a Canon A630, that takes unbelievably good pictures in AUTO -- if you're taking pictures of people or things other than CRT images. So far I've played with exposure time. Longer exposures (under 1/8 second) seemed to darken the image for some reason and so 1/15 second seems best.
Attached are G1 waveforms (taken waiting for the Times Square ball to drop), plus my best shot of the screen image those waveforms generated. I think you can see an improvement over the other (pre-cal) color bar image. The screen looked okay to me through R, G, and B filters. The A630 overexposes my scope shots, but you can see the red trace amplitude is greater than green and blue, as it should be driving a 15GP22. Vertical sensitivity is 50 V/cm.
I have yet to check the I gain (later today maybe), but the control is so narrow I will be surprised to find a problem there.
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1-1-2008
Yesterday after downloading images to the computer and while still connected to the computer I found a menu showing sRGB. There were options for many other color spaces including 1953NTSC, which I promptly invoked. I can't believe it was that easy to shift an A630 to the coveted original NTSC specification. Anyone familiar with the Canon A630 who can make some sense of it? The three shots below were taken after the 'change' if that's actually what I did...
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