Re: Panasonic vs Sony for green screen production

Adam,

I think you touched on something that I would like to elaborate upon: technical specifications of cameras.

Specs of cameras are the "hidden keys" to many facets of production. You are correct in your realizations of specs too! So with out ANY biased, as you think I have some, I will ask you to ask your self some questions in trying to determine a format, and camera to use in YOUR productions.

* What is the native resolution of the camera? That is what is the imager size? NOT the "final output" size of the picture, but what is the size of the picture when it's captured? Typically one thinks of 1920 x 1080, 1440 x 1080, 720 x 1280, 960 x 1080, 960 x 540, 320 x 240, etc.

* What is the size of the imager of that camera? 2/3", 1/2", 1/3", 1/4"

* What is the codec and data rate of the camera (along with the native imager size)? (bonus question: how efficient is that codec?) HDCam SR-440 Mbps/880Mbps (1920 x 1080), HD Cam-144Mbps (1440 x 1080), DVC Pro HD-100Mbps (960 x 720), AVCI-100Mbps or 50Mbps (1920 x 1080, 960 x 540), XD Cam HD (422) - 50Mbps (1920 X 1080), XD Cam HD (420) 35/25/18Mbps (1440 x 1080), HDV-25Mbps (960 x 1080), AVCHD-18Mbps, etc.

* Type of media and it's associated cost: HD Cam Sr (tape), HD Cam (Tape), DVC Pro HD (tape and / or P2 card), XD Cam HD (optical disc), XD Cam EX (flash memory), HDV (tape/compact flash), etc. Then figure out how much it will cost to ARCHIVE that media.

* What is the final product? Where will it be shown? (broadcast television, DVD, film, Blu-Ray?) Lower quality cameras will show artifacts and other imperfections when show on larger surfaces.

* Noise floor. What is the signal to noise ratio.

* Cost. What is your budget? This is why so many camera manufacturers have many models to choose from. They mix the elements listed above to allow the user to make choices. Price can also dictate compromise in the "mating" of the other criteria to produce the final image.

Typically there is a price tag associated with each element of these criteria. A camera with a larger native resolution size (1920 x 1080) with a larger imager/chip size (2/3"), and a high data rate will cost more than a camera with out those features.

Often, these days you'll find a mix match of the three elements. There are cameras being made that have 2/3" imagers/chips/sensors, with a native resolution that is not "full frame" HD, with decent data rates. The question is now, "will the image be the same?" No. To become "full frame" HD, which is now established as 1920 x 1080 for broadcasting, there has to be a post acquisition (after captured) of signal process (on the cameras with smaller imagers), called "up sampling" to make that image "seem" full frame.

These are marketing efforts by camera manufacturers "keying in" on buzz words in the broadcast and production communities, using them to sell product. They know decision makers out there, KNOW certain terms, and therefore USE those terms to sell cameras. If one doesn't look at specifications of cameras, or worse, doesn't understand them, they could indeed purchase something that will NOT fulfill their needs. This is great for the camera manufacturers as they sell twice as many units! It has been suggested to me, by many of the TOP engineers in the HD world that one acquire and READ the "white papers" of many of these cameras... Manufacturers aren't allowed, by law, to use creative prose here to mask the actual specifications of the camera. Often brochures, ads and the like will use words to confuse the buyer.

"Color Space" may surprise you! For example, one would agree that the WORK HORSES of the HD industry in the tape field are and have been, the F900 and the Varicam! Their respective color spaces are 3:1:1 and 2.65:1:1! Most people don't know that! What makes these high end cameras work so well in the world of chroma key work is their imager sizes, and CoDec. They are 1920 x 1080 HD Cam and 720 x 960 DVC Pro HD (however BOTH cameras capture a different frame size and utilizing their respective CoDecs (compression and decompression) capture images at 1440 x 1080 and 720 x 960, and playback at the "known" frame sizes of 1920 x 1080 and 720 x 1280.

This is why I said in an earlier last post to not get hung up on "color space." It is one of those buzz words often misunderstood, and often over used to sell equipment. Remember that the camera's color space will only be as good as it's native resolution. More over, if you are shooting green screen the MOST IMPORTANT FACTOR is luminance ! Therefore the "4" is the most important and relative number of the color space (4:2:0, 4:2:2) (Green, Red, Blue). The red and blue channels, if you will, don't come into play! The luminance is the "green" channel! You are "illuminating" the background to be replaced! If it's a FLAT luminance level on a wave form monitor then it will key out! This is why I've always had great luck in keying many different formats.

So now, all things equal, all cameras have a "4" in the luminance, one looks at native resolution, CoDec (and efficiency of that), imager/chip/sensor size, and most importantly, NOISE FLOOR!

One of the camera manufacturers that you are considering in using, utilizes standard def imagers in their lower priced HD cameras, so there is already interpolation to get the signal from SD to HD! There's even more interpolation when you want that signal to be "full frame" HD. Another little known fact.

I suggest that you sit down and make a chart, it will only take a few minutes, of the models you are looking at. Include each model, their native resolution size, the size of the imager, the signal to noise ratio, and the data rate of the recorded material. You might be surprised at the results! (I would search "white papers" for each model... brochures and websites may be misleading!)

One of the things we do on the ICE Team is to educate people in the world of HD. It's no longer simple. There are several factors that should influence one's decision to use a particular format, I've outlined those already. Often cost is the first. If an individual understands nothing on the technical side, gets caught up in the buzz terminology, cost will win in the end. That may work for some individuals and that is great! We hope that by bringing difficult terminologies to light, one can understand those terms and make an informed decision. If that ends up being a Sony camera, great! Perhaps Sony DOES NOT have a model in your price range with the specifications you need. That's alright too! That's why we live in a world with options.

I'm glad you realized that the technical side is as important as the artistic side in the world of HD production. With that knowledge, you will go far!

Curt

Curt Pair
Picture This Productions
Sony ICE Team
F900/F800/F350/PDW700/EX1/EX3/D790/D600
Adobe Premiere Pro CS3 HD/Matrox
Phoenix, AZ