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segal3

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Posts posted by segal3


  1. Hi everyone! Just two weeks ago we returned from the Wetpixel Alaska Expedition 2011, led by Jason Bradley. We had great weather and truly cooperative wildlife, topside and underwater.

     

    Jason and I have written about the trip in a front page post that includes some really excellent imagery from the participants: Wetpixel Alaska Expedition 2011 Trip Report.

     

    What do you say - willing to join us on our next cold water adventure?


  2. Shot with Nikkor 105mm, Kenko 1.4 TC and Canon 500D diopter!

    This is my favorite combination for basic supermacro (well, with a Canon 100 in place of the 105), though I found myself wishing for more magnification on the recent Wetpixel Alaska expedition. If I recall correctly, it provides nearly 2:1 with only a stop of light loss.


  3. It'd be nice to see an improved version of the discontinued Inon Optical Converter D - a small device that plugs into the housing bulkhead and converts the electrical flash signal into an optical pulse (perhaps having 2-4 ports to plug fiber-optic cables into). Combined with these adapters (or any strobes that support optical sync natively), a small price to pay for never having to replace a broken sync cord!

     

    I think the Converter D's limited compatibility with non-Inon bulkheads or strobes was its downfall.


  4. Back-of-the-envelope engineering suggests that the forces on the dome are rather large: the internal area of the dome is, roughly, 70 square in or 400 square cm, a temperature differential of 20 K is equivalent to a pressure of about 6.5kPa or 1 psi: the expanding air exerts a force of 70 lbf or 30kg on the dome!!

    Would like to see your math here?

     

    Force to separate the dome from the mount is in the axial (not radial) direction. Projected cross-sectional area will overestimate this force - you need to take the integral of the load in spherical coordinates, which (quick calculations) seems to only result in ~33 lbf (15 kg) separation force on the dome.

     

    Anyway, this is insignificant relative to the pressure on the dome of the water at depth, which (as we learn in basic training), increases at ~1atm/10m. At 1m, the external pressure of the water on the dome is 16.2psi (or a delta of +1.5psi assuming 14.7psi ambient air conditions), already outweighing what would have been an internal 1psi increase.

     

    It seems like something failed, but as Ryan suggests, I wouldn't attribute it purely to the temperature change - all domes should tolerate these conditions.


  5. Selling a new old-stock Ikelite Digital TTL Dual Sync Cord (#4103.52). I've had this cord as a backup/spare for a couple years, but realized I no longer have Ikelite bulkheads to use it with!

     

    Never been used in the water - cable and o-rings appear to be in fine condition, and comes with original manual and Ikelite o-ring grease packet.

     

    Retails for ~$160 USD new. $125 USD shipped CONUS.

     

    20110227_88W7889w.jpg

     

    PM inquiries. Thanks!


  6. We did dive a few of the Marine Protected Areas at Santa Cruz - a definite change in the quantity and health of the fish life.

    20110219_88W7543.jpg

     

    But there were still sites where I wished for a Garibaldi or Sheephead to provide some dynamism.

    20110219_88W7588.jpg

     

    All with the 24II - am really enjoying that lens. Hopefully Joe will post a few of his shots, as well.


  7. In March 2009, I joined the second leg of the Wetpixel Ultimate Indonesia expedition. We traveled from Ambon through the Banda Sea, stopping to visit Fort Belgica, climb (and subsequently tumble down) a volcano, and dive with the sea snakes of Gunang Api, before continuing on to Alor and Flores. A small dive site consisting of little more than a sandy slope on the edge of Alor provided three days of muck diving.

     

    A long delayed gallery posting, I admit - Indonesia 2009. Appraisals always appreciated.

     

    20090327_88W7461.jpg

    Banda Sea, Indonesia

     

    20090325_88W7074.jpg

    Ambon, Indonesia

     

    20090407_71D1313.jpg

    Beang Abang, Pantar Island, Alor, Indonesia

     

    20090404_71D9998.jpg

    Wetar, Maluku, Indonesia

     

    Special thanks to Eric Cheng and Graham Abbott for the organization of the expedition!

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