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LX5 10bar housing + TTL Strobe

Discussion in 'Panasonic Planet' started by Aquanut2, Dec 31, 2010.

  1. shaker

    shaker Nassau Grouper

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    I used the 5" 10Bar dome port with the LX3 and LX5 combined with Panasonic converter or Sony converter, both give 18mm underwater. It was discussed here:
    http://www.scubaboard.com/forums/panasonic-planet/351751-lx3-river-underwater-photos.html
     
  2. derway

    derway Nassau Grouper

    # of Dives: 500 - 999
    Location: pasadena CA
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    I know all that.

    With Ikelite, the problem is that without a dome port, using a wet lens, on a flat port, that barely has coverage for a 28mm angle, your going to have to zoom way in, on the 24 mm. And not get much value out of that nice wide angle.

    And even 28mm flat port has lots of distortion. Not very good IQ at all.

    The flat fronted 'converter lens' that 10 bar puts out, looks like anything but a dome port. The dome port option on top of that who knows..??

    None give the IQ of a straight dome port.
     
  3. slowhands

    slowhands Divemaster

    # of Dives: 500 - 999
    Location:
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    The function of a dome port is twofold: it is a water seal, and it acts as a lens. It is a lens solely because of the difference of the index of refraction between air and water (1.0 vs 1.33), not due to varying thickness. For best performance, the dome surface should be equidistant from the nodal point of the lens behind it.

    If a converter lens has a flat front surface, it can still effective for wide angle. If the front element has a flat front surface but is concave on the rear side, it will act to widen the image in the same way as if it were curved on the front surface. What matters most is that the lens is concave, not the flatness of its front surface.

    Optical designers often decide to make the front surface flat for practical reasons, such as making the surface less likely to be scratched if set on its front. I have seen a lot of scratched dome ports, so this is an important practical consideration. All of the wet wide angle lenses I have seen had flat front elements.

    Common wide angle converters are made with multiple concave elements in front that widen the field of view and a rear group that magnifies and focuses the image.

    A cutaway drawing of such a lens is shown below. This lens is a .5x wide angle converter. It has 2 concave elements in front that widen the image and a rear group of 2 elements, that magnifies and focuses the image. This is a fairly typical design, while wider or better performing lenses may have say 5 elements in 4 groups.

    The second lens shown below is larger, for 72mm filter rings. It also is a .5x lens. Due to its larger size, it is simpler optically to keep costs reasonable (3 elements / 3 groups). This lens is huge, 125mm (5 inches) in diameter. By coincidence, the front surface is flat.
     

    Attached Files:

    Last edited: Mar 29, 2011
  4. shaker

    shaker Nassau Grouper

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    Is the IKELITE WD-4 Domeport what you are looking for?
     

    Attached Files:

  5. derway

    derway Nassau Grouper

    # of Dives: 500 - 999
    Location: pasadena CA
    85
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    Yeah, shaker thanks. That dome is the one they used to sell for a couple of p&s digicams, but not offering any more.

    Thanks for your great shots and setup with a true dome on the lx3/10 bar thread. Good work!

    I wrote ikelite, a number of weeks ago, asking if we could get an lx5 housing with a dome port, and was told no. Too bad, as I really like to use wired TTL strobes...

    I haven't been very active on this board, ever, (I've been much more active on wetpixel).

    I've been doing underwater photo, since the early 90s, with an n90s film SLR, and lots of lenses, in ikelite housing, with various flat and dome ports. 3 generations of digital cams now, and looking for the 4th.

    I keep almost getting ready to buy a gh2, but the prices of the lenses are insane, and they just aren't that good, (no f2.8 zooms for instance).

    Then I think I'll give up, and go d7000 or t2i, but I really don't like traveling with a giant kit any more. And I sure like the option of shooting with the LCD underwater.

    Maybe the sony a580.. No good control over video or auto focus, but otherwise very good IQ and live view with quick focus mode.

    Maybe wait one more generation for the next NEX, or better lenses to come out.

    So I go back to the best P&S available, (with fast AF high on the list), and the LX5, or the XZ1, are about it.
     
  6. slowhands

    slowhands Divemaster

    # of Dives: 500 - 999
    Location:
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    This is not the correct dome port for the M67 port on the Ikelite LX5 housing. It is for bigger ikelite ports, such as on their G11 housing.

    For the ikelite you need an M67 version, available as a Fantasea 5137 Bigeye M67 wide converter. It is not an extreme wide angle, basically only a .7x. You will get wider angle views from the .56x Ikelite W20 or the superior Olympus PTWC-01, but the Bigeye is only $220, so you do get some improvement for modest outlay. Here is a source:
    Fantasea BigEye Lens M67 Wide Angle Lens - Underwater Photography - Helix Camera & Video

    I have ordered a Dyron wide adapter to compare with all these and will report on it when it arrives.
     
  7. derway

    derway Nassau Grouper

    # of Dives: 500 - 999
    Location: pasadena CA
    85
    3
    0
    Slow hands, I keep trying to say this clearly.

    That is a wet lens. It fastens on to a flat port. You cannot get decent IQ by trying to get images through with a 24mm equiv FOV lens behind a flat port. Nothing you do in front of the flat port will fix the fact that the light gets blurred and lots of chromatic aberration added going through a flat port at those angles.

    Even using 28mm through a flat port is marginal. No way will 24mm work, with sharp corners.

    If we want to use the 24mm end of this camera, it must be through a dome. Otherwise, we can just zoom in to 28mm, and then why bother with this camera?

    Here are some samples, to illustrate:

    wide angle wet lens for 24mm - Wetpixel :: Underwater Photography Forums

    Hope this helps.
     
  8. slowhands

    slowhands Divemaster

    # of Dives: 500 - 999
    Location:
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    Thanks for posting the link to the Wetpixel discussion. I happen to have that housing with the slightly curved port for the CP5000 - it's not much of a "dome" but it did help back in the day. I'm not sure how he mounted the LX3 in that housing, but not many of the buttons would line up. You would have to center the lens, re-drill the tripod screw hole and hope the shutter lined up. Good enough for an experiment. The LX3 and LX5 lenses are the same, so this is very interesting.

    I am well aware of the advantages of domes. But this discussion was about available solutions, not imaginary ones. If you want to use the LX5 behind a commercial dome, 10Bar. Ikelite has made a decision not to offer a dome for their housing as posted earlier.

    There is nothing stopping an experimenter from building one, if you want to use the Ikelite housing as a starting point for its TTL flash capability.

    You say, "If we want to use the 24mm end of this camera, it must be through a dome. Otherwise, we can just zoom in to 28mm, and then why bother with this camera?"

    It's not a perfect world. There are several great cameras out that have strengths and weaknesses. I bother with the LX5 because it has many features I like. Wide angle is only one parameter. The LX5 has by far the best video of the current crop of compacts. It will close focus easily, without having to switch to "supermacro" mode, and you can use flash when close (you cannot with the XZ1). Those are just some features I like, but the XZ1 has strong points too. I don't want to get into the relative merits, because my point is all these cameras all have some very good points and some irritating weaknesses. Same with housings. It's not a perfect world.

    The lack of a dome port is something you can correct, by building one yourself. It ain't rocket science.
    DIY small dome port for CFWA - Wetpixel :: Underwater Photography Forums
    P6000 Housing - a set on Flickr
     
  9. shaker

    shaker Nassau Grouper

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    Hi

    I asked Michael Finger if he has a TTL conversion solution for the kelite DS-161 strobe and the Panasonic LX5. He responded (i try to translate from german):
    "yes, this solution exists... In which housing should the converter built in?"
    The converter ist available only including assembly and function control, i don't deliver the simple converter"


    Michel Finger, for those how don't know, develops und sells different products for underwater photography like converters, arms...
    www.mikedive.de
     
  10. shaker

    shaker Nassau Grouper

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    Good wet lenses are designed with optical correction for flat ports, they usually have more then 2 elements, that's why they are bulky and heavy, and that's what slowhands tried to explain.

    - For the LX5 you have at least 2 choices: the Zen WA lens 67mm or the FISHEYE FIX UWL-04 M67, both are designed for 28mm lenses.
    unterwasserkamera.at - FISHEYE FIX UWL-04 M67

    - For dry domes, you have the 5" 10Bar dome, or the Recsea REC-DOME-8 for the Reacsea housing.
    Plongimage - Dme cristal pour 8mm caisson Recsea
    Notice, having a dome port doesn't mean you will have automatically good IQ. Not all lenses or all WA converters are good behind a dome port. I had bad experience with the Panasonic LW46 but a good one with the LWA52 using the same dome port.
    Also, the 10bar dome port gives better IQ with the converter then without.
     

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