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fer_abella

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Posts posted by fer_abella

  1. Posted

    The only time I had a problem was with an o-ring installed sideways on a control rod I had just worked on, and that leak took about 10 or 15 seconds to go from 15 inches of Hg to zero.

     

    Sure your system save you from a problem. A latch is blind about that kind of probblems. Safety relies in operator and mounting. Vacuum checks the housing completely.

     

     

    Very interesting the ideas of about a DIY project. More like that ?

     

    I did not express myself completely. I will probably add a latch or two at the end.

     

    I trust more in the vacuum than in the latches, but adding a safety latch is inexpensive and can be nice if because a bump or a crack the vacuum is gone. You should have a safety in case an oring is wrong and you lose vacuum some time after mounting housing.

     

    I believe 10bar uses latches in part because of the answer from moderator. People is used to them and do not like new things. Perhaps your system is better, but if it is not percived as so you will not sell one. And it is not percived now.

  2. Posted

    Thank you.

     

    This is the solution i will probably build inside the housing.

    It is easier than the valve type solution and more problem free.

    I will use a pipe of lexar or other similar material.

    Think about a 100cc ¿sringe? with a piston that can be locked at the end of its displacement, when vacuum has been formed inside housing.

     

    But i would like to know how 10bar produces the vacuum with its air lock just to check volumes and ways of designing mechanism.

  4. Posted

    I like the airlock system better than latches because of the use of physics to obtain 100% watertigh security. :)

    You can not beat physics laws on that. :)

    When nikonos V was the camera for UW photo, airlock systems were an upgrade made by some good artisans. :)

    They did it because good reasons.

    Now i understand more why it is not used widely. :)

    People is better prepared to latches. They trust them more than physics.

    For me is like using flat o-rings instead of "normal" ones.

    Remember that before the use of the ones we know today, the flat model was the avalaible one.

    I have manufactured some uw housings for instruments based on nuts and bolts.

    10 bar use a reliable method and sell 100s of housings, i prefer theis method.

    If somebody can publish photos of a real housing with airlock i will like it.

    Thank you ;)

  5. Posted · Edited by fer_abella

    I understand the concept. I just want to know experiences, drawings, parts, schemes to add a secure, easy air lock to my homemade uw housing. I have lathes and milling machines to manufacture it.

     

    Concept : If you lower the internal pressure of the uw housing to less than 1 bar when you are at sea level you do not need latches as atmospheric preassure replaces them to mantain close the door of the housing. When summerged, this effect continues. To open the housing you should relieve internal pressure. Think about an airtight case in an airplane. You open it in the flight, you close it, you can not open it in land if you do not use the relief valve of the case.

     

    Advantage : With homemade uw housings, it is good this kind of locking procedure because it does not work if housing has a leak. It checks itself as watertight BEFORE entering water. Just try to open it, if it open lock is wrong.

     

    Design : There are a lot of forms to use that design. Some are better than others. I would like to know one good one. Easy to machine if possible. I have my own design, very easy and very effective, but out there are people with more experience and i would like to learn from them.

     

    My idea is to use

     

    (a) a valve and an external device (a bicicle pump like thing) to extract some air from housing.

    (b) a kind of sringe in the inside of housing operated from outside by a bar that you can use to decrease internal pressure and lock in place securely to mantain that low pressure.

     

    HELP :

     

    Do you know how works different tyoes of air locks?

    Do you know how 10bar lock works in detail?

    How much air do you extract from the housing using that kind of air locks?

    Anything related to that will be of great help

    I am sure somebody did it yet but google does not show it nor search here

     

    Thank You

  6. Posted

    Hi,

     

    I sometimes make some articles to magazines. My UW photographs are always using wide angle (nikonos + Sea-Sea 15mm) with strobe, because full body and ambient are the more usual photographs. Size of camera are of extreme importance for me.

     

    I would like to know if somebody have used a digicam and wet wide angle (for example my Canon S70 with de INON wide angle for 28mm lenses) and how he/she thinks it compares to a film SLR housed or a nikonos setup like mine when you compared the digital products of both.

     

    I will find my onw appreciation and i am sure the photograps taken with the new setup will be good enough, but i am curious about other people experiences.

     

    Regards. <_<

     

    I am sorry if this same topic was treated, but i searched and i did not find answers.

  8. Posted

    The S&S 16mm or 20mm can be used with the WP-DC 40. You'll need the S&S DC300 Conversion ring which must be machined to fit the DC 40 Housing. You'll also need to zoom out beyond the 35mm zoom postion in order to avoid the vignetting effect. We can supply and machine the conversion ring for you if you're interested.

     

    I could be interested :)

     

    Would i obtain 90% of performance of INON 450$ alternative with a 100$ lens which is also 4 elements in 4 groups, wet changeable and 90+ degrees of coverage?

     

    What about the 5.6 aperture??

  9. Posted

    I have searched the forums about that question but nothing seems to exist.

     

    I believe the idea is bad as it will vignette or something worse, but i am unsure. I would like somebody more expert to help me about the correct reasoning or experience.

     

    Thank you in advance.

     

    It is because i can borrow a Sea-Sea 16mm wide angle adaptor for nikonos from a friend and i do not know if it could be a thing to test.

     

    :)

  10. Posted

    Hi,

     

    I have one very light scratch in my video wide angle.

    The manufacturer says it is very easily cleaned with a light lens polishing it can do for 350$. A friend that retails uw housings says that it can be made almost disappear with a very well done light polihing at home. I am very reluctant to that idea but perhaps he is right.

     

    What do you think? <_<

    Do you ever saw this poslishing process made at home? :D

     

    Thank you :):)

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