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  1. #1

    Pixel Count Confusion

    A technical question on CCD size and pixel count please??

    Explain these specs on the older Panasonic Proline cameras

    (1) DVC15 - 3 x 1/4" chips and a pixel count of 270K x 3
    (2) DVC20 - 3 x 1/6" chips and a pixel count of 290K x 3
    (3) DVC30 - 3 x 1/4" chips and a pixel count of 470K x 3

    What makes the count different (and even higher on smaller chips)

    Just for interest the Panasonic GS 120 and GS200 have identical lenses and both use 1/6" x 3 CCD's yet the GS120 has a pixel count of 290K x 3
    and the GS200 has a pixel count of 540K x 3

    I'm sure my buddy Nagar can answer this one or maybe our resident experts????

    Chris

  2. #2
    If those numbers are accurate, all are 3 sensors, and are for the sensors used for video (more about this if you ask and it's not quite as late when I read it ), I'd expect that the sensors with larger numbers of pixels at a smaller size are just more closely packed (leading to more crosstalk but more base resolution). The "size" is just the physical size of the sensor (and usually listed as a nominal size when seen as a simple fraction) while the pixel count is the full pixel count of the sensor (usually not all of the pixels are sampled for the resulting image).
    Eric Adler (tonsofpcs)
    http://www.videoproductionsupport.com/ Chat at: http://tinyurl.com/vpschat
    Follow me on twitter: @videosupport @eric_adler

  3. #3
    Thanks Eric
    I guess that the chips are either manuafctured differently OR they are using pixel shifting (like the Canon XL1 which only has 470K but shifts them to achieve a much better resolution)
    I didn't want to confuse issues with "total" and "effective" pixels so I did realise that not all are used for the image

    Your comments are much appreciated

    Chris

  4. #4
    Apologies I've been quite tied up with work.. and work is getting busier as peak session for this year begins from July till Christmas! I believe tonsofpcs has explained it beyond what I can do. I'll just top a little cherry onto the wonderful cocktail.

    Correct me if I'm wrong, but I don't know if pixels can be counted literally on the chip, rather it is on the monitor... Pixel (picture elements) is on monitors and photosites are on chips. Anyhow, I'll just stick with the term pixel.

    The reasons I can think of correspond with both tonsofpcs and yourself.

    1. Physical size does not mean more pixels
    In fact, not squeezing pixels together is good, and allows better performance in low light (more pixels on smaller chip means less light can be gathered, smaller surface area?). Not the best example but that's why my 5-megapixel DSLR is tons better than a 8-megapixel compact digital camera, save superior optics and processor.

    2. Pixel shifting
    I'm aware but I don't understand this technology as much, but I guess you know.

    3. DSP and other little but not so little things
    Your digital signal processor is very important. Actually what lands on the CCD/CMOS is analogue till it is converted by the DSP. Just having a great sensor chip is not good enough. Other factors like optics (as Chris, you have made the comparison) count too. Everything contributes to the final product.
    There's no bad camera, just a bad user
    Loong . Singapore

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