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20mm lens in Flat Port

Discussion in 'Tips & Techniques' started by Compressor, Apr 27, 2021.

  1. Compressor

    Compressor ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: NYS
    3,431
    1,841
    Wondering how this will work underwater:

    If I put a Nikon 10-20 mm lens set @ 20mm in a Ikelite housing and a flat port how will the images be seen underwater? On land, the image is fine. (I have an issue with large dome port for travel on this coming trip; hence reason for asking). Nikon D500 is the camera (AP-C).

    I have a feeling that the camera will not be able to focus as in some lens/port combination where a 4x diopter lens filter is needed.
    Thank you.
     
  2. Barmaglot

    Barmaglot Contributor

    # of Dives: 200 - 499
    Location: Israel
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    Pretty terrible. Focusing shouldn't be a problem, but distortion will be quite significant, and you will lose significant amounts of field of view. Here's a Sony 10-18mm behind flat port @ 10mm:

    Bp1SK9S.jpg

    And the same lens @ 18mm:

    WZLhzK0.jpg

    For comparison, the same lens @ 10mm and 18mm behind an 8-inch dome:

    eWaJWvh.jpg

    JrWdQnl.jpg

    If you can't bring along a proper dome, at least consider getting a wet dome attachment for the flat port; this will go a long way towards correcting these aberrations.
     
    kelemvor and Compressor like this.
  3. Compressor

    Compressor ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: NYS
    3,431
    1,841
    Thank you @Barmaglot. Very helpful.
    Will look into a wet dome attachment. Did not know it existed for Ikelite.
     
  4. Compressor

    Compressor ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: NYS
    3,431
    1,841

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