Info on how to take screen shots? Where??

Computer or camera?

Camera, use a tripod--d'uh... As far as ISO settings, etc. What type of camera are you using?

turn your flash off and use a tripod. Im no expert, but it first starts with the source which in this is is pasuing the movie at a frame which looks good.

Here is what I got using a crappy HP cam on a tripod with no flash. Im sure if I would have turnned the lights off and got into a better position the shot could have been 100% screen and would have turned out pretty good as far as a screen shot of the movie.

I just set my Olympus E-300 to auto with flash off on a tripod and it works pretty well. Also set 2 second timer so I 'm not touching it when the shutter opens.

If you're using a camera with flash off, your feed should be a 1080P feed so when you pause, you get a frame instead of a field repeated twice (1/2 res). Note there is an A-->D step when your camera has to capture the screen, and this is arguably a large source for generation loss --- the color settings will be off from what is in the actual video.

Otoh, from what I'm guessing, the best comparison (where you can do pixel deltas) come from the ability to decode the video stream directly and save the decoded YUV into disk to convert into png. That is the only lossless 'screen' capture method.

First start of with the DVE or avia disc and start taking pictures of the grey ramp test pattern pictures. Best for this would be the gray ramp pattern with top half of the screen from black to with and bottom half vice versa.

Use a tripod and a fixed position and zoom setting for all your normal screenshots. (Best to use a standard lens with a fixed focal length.)

Go for manual exposure and use the most optimum aperture setting for the lens used. This setting should give minimal vignetting of the camera lens.

Now in a dark viewing room (without flash) just start taking shots of the grey ramp pattern and vary exposure time until you get the best exposure of the grey ramp. If exposure is to long then the grey area near the white area will clip and if too short the grey near the black area will clip.
Shouldn't be too difficult to get the exposure time that shows the best gray scale ramp.

You now have calibrated your exposure setting with your projector screen combination.
Repeat this over the lamps lifetime to keep the screenshots evenly lighted.
Also keep a record of gray ramp shots with the original settings to get an impression of the lamps light loss over its lifetime.

Note down the lens settings and use these settings for every screenshot from now on.

This way metering is avoided and your screenshots should always give the correct impression of dark and light scenes.

Now color can be tricky. Start of by setting your cameras white balance for6500K.
This should get you close.

Most likely the color gamut of the camera doesn't match the color gamut of you projector.

This means photoshopping until the colors look similar to the colors on the pc screen match the projected image.
Using screen shot from the smpte test screen makes it fairly easy to measure the captured colors in photoshop and figure out the corrections needed.

Use some reference images from DVE for skin tones and other colorful images to tweak the settings a bit.

Use this workflow to apply these same corrections you found to work best to your screenshots.

This works best if you have your pc screen calibrated too....

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http://www.avsforum.com/avs-vb/showt...1#post13754431

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