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LX5 10bar housing + dome port question

Discussion in 'Panasonic Planet' started by HolgMaster, Oct 24, 2010.

  1. Ryan

    Ryan Dive Shop

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    Shooting 16:9 is merely cropping strips off the top and bottom of the native 4:3 sensor. It just so happens that would also chop off the worst corner performance.

    Personally I'd shoot 4:3, capturing everything I could, then decide on a 3:2, 4:3, 16:9, or square crop when I'm sitting at my comfy chair with my big monitor breathing through my nose.

    See the post from Panda in this thread for comparison between a flat port and dome:
    wide angle wet lens for 24mm - Wetpixel :: Underwater Photography Forums

    Fortunately one can have both on the same dive in one upcoming solution.
     
  2. Puffer Fish

    Puffer Fish Captain Happy ScubaBoard Supporter

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    Location: Knoxville, TN
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    Ryan, You need to do your research a bit better before posting. The LX-5 and the GH-2 don't work that way. They have a special larger sensor that actually increases the field of view.

    Specifically, with the LX-5, here are the image sizes compared to a S95:

    4 x 3:

    S95: 3648 x 2736
    LX-5: 3648 x 2736


    16 x 9:

    S95: 3648 x 2048
    Lx-5: 3968 x 2232

    It actually would make the corners worse. The corner issue in 4 x 3 with a flat port, at it's widest appears to be identical to what it is on land. I believe the lens distortion is being corrected with software in the camera.

    Those are the only two camera's made where that is the case. Why Panasonic goes to all the trouble to make these two sensors is a bit unclear. The Oly seems to have the same sensor, but does not use the whole sensor (also very odd).

    One still looses a bit, but at least one gets something in return.

    I have not tested this with add on lens, need to go over to the pool and do some test shots, but expect this will cause some problems. Might be able to do that this weekend.

    I've done comparison shots, and it recovers just under half of the field of view lost by using a flat port, and given the 24mm equv., it is not far different from a 28mm equv. under a dome. Obviously not a wide as a 24 under a dome.

    Your post is accurate for every other camera.

     
  3. shaker

    shaker Nassau Grouper

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  4. Ryan

    Ryan Dive Shop

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    Merely should have been mostly in my post. This is minutiae, but the actual diagonal fov is not wider in 16:9, it is widest in 4:3. The horizontal image area is a bit wider, but diag fov has historically been the matrix wa lenses are measured by.

    Assuming horizontal and vert pixel pitch is consistent:
    4:3 Aspect Ratio - 3648 x 2736, Diagonal = 4560
    3:2 Aspect Ratio - 3776 x 2520, Diagonal = 4540
    16:9 Aspect Ratio - 3968 x 2232, Diagonal = 4553

    Given that it is an accepted still image format, and that it captures the most data, our lens testing will be done at 4:3.
     
  5. Puffer Fish

    Puffer Fish Captain Happy ScubaBoard Supporter

    # of Dives:
    Location: Knoxville, TN
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    I checked the actual raw image and it is 3980 x 2250 =4572

    The first image was the standard jpeg, which is a bit narrower.

    Looks like this:

    Sorry for the terrible image, was shooting in surf while snorkeling:

    [​IMG]

    If you go back and compare the first image I posted, and look at the small fish in the upper right, that trivial increase from 3968 to 3980 makes a very easy to see difference, and remember that is happening on both sides.

    I understand why you test that way, as every other camera just crops the image.

    But consider that if the objective is to have a wide image, the LX-5 with it's 24mm lens, and with a wider aspect ratio starts out with a field of view over 45% wider than a 28mm on any other camera at 4 x 3...Putting a 28mm under a dome will not be as wide.

    And best that I can tell, while the corners may not be perfect, they are not terrible. will see if in the next month I can get some test images.

    And that trivial 9% wider image makes that 24mm equal to (in width) something around 21-22 mm.
     

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