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Posts posted by herbko

  1. Finally got to dive with my new lighting setup.

    Two YS90DX both on slave mode synced to the built-in flash

    filtered with a piece of unexposed slide.

    Strobes were set to the "Pre" and slave mode.


    It worked !


    I had tested it all indoors and it had all worked,

    but when I tried it at the parking lot just before the

    dive, it didn't trigger! I was a little concerned.

    I thought about it a moment and realized the bright

    sun light probably saturated the strobe sensors.

    Tried it again in a dark area in my car and the strobes triggered.


    Jumped in, and eveything works. Even the shots at 10' depth triggered.


    I'll post some shot when I have the time to upload.



  2. Great Idea. I spent an hour or so trying it out last night.

    I've posted my results in a reply to another discussion




    This is better than reflecting the light up since the sensor on the

    YS90DX faces the front of the strobe. This should be more reliable.


    Now that I thought a little about it. The pre-flash could be an advantage

    in this scheme, it keeps your strobe from being set off by other photographers

    near by. Does anyone know how long is the "memory" of the YS90DX?

    That is how much time can elapse between the two flash and still have the

    strobe triggered. Maybe I'll try some tests this weekend.


    Now if only the weather would cooperate so I can try this out on a dive.



  3. Definitely get a strobe instead of a continous light. The strobe will be brighter and allows you much more freedom in setting the exposure of the background.


    I just did some experiments per rstark's suggestion of using unexposed slide film to filter out visible light and let the IR trigger the slaves using a C3000 and a YS90DX strobe. I think rstark's right about the slide letting the IR through, but he's wrong about the pre-flash not having any IR. I got the strobe to trigger without using a fiber on the strobe's "Pre" mode.

    If I set it to the normal "On" mode the stobe always triggered on the pre-flash and my photo alway turned out black.


    It makes sense when you think about it. Both the pre-flash and the main flash comes from the same filament. I think the only difference is the duration the filament gets turned on.


    I did the first set of tests by taping a piece of unexposed slide film right on the camera's flash. For the second set, I removed that film and covered the inside front surface of the housing with unexposed slide film. Same results.

    It worked very well. The only way I got this to fail is by going outside and just shooting up at a dark empty sky. The YS90DX didn't trigger in this case. Also not surprising since the light sensor is on the front of the strobe. No reflected light, no trigger. I think it's probably good to have the strobe not trigger when the subject is too far to reflect much light; it wouldn't help light the subject, only create backscatter.



  4. I've also been thinking about upgrading, and I'm leaning towards

    the G2. The biggest advantage of the G2 is the raw output mode.

    If you do any post processing it's best to start with the raw

    image without having the camera do a white balance beforehand.

    The jpeg or tiff output is 8 bits/color, and the CCD is better

    than that which means the dyanmic range is better in the

    raw output mode. Tests by Phil Askey show better than

    9 bits dynamic range from the CCD of a G1. Hopefully the G2

    can do as well. See




    An extra bit of dynamic range is very significant. It'll

    give you better details in shots with very bright and very

    dark regions. With 9 bits of dynamic range you can compensate

    for being a full stop underexposed and produce a full range

    8 bit output.


    I do agree that the coolpix 5000 is better at macro,and its

    zoom range is better for UW photos, but these are things you can fix

    with add-on lenses.






    [Edited on 3-12-2002 by herbko]

  5. This is probably the oldest one in service. I put this together January 2001,

    before pre-flash compatible strobes were available. Had to make my own optical fiber

    link to the Ikelite A35 strobe.





    Here are a few links to some of the photos from this setup.












    [Edited on 2-8-2002 by herbko]

  6. Just noticed another interesting "feature" in this message board software. I did not specify a location in my profile, and the software puts in the location of the last entry for my location.



  7. I tried to edit my message after it was posted to clean up a sentence, but I couldn't get the original message replace with the new one. The two buttons, "Edit Post" and "Preview Post" doesn't do the trick. What am I missing?



  8. Nice shots Don.


    What output file format did you use?


    I've been thinking about replacing my C3000

    with a G2. To me, the biggest advantage the

    G2 has over a C4040 is the Canon Raw output

    mode. For color post processing, it should be

    better to start with the raw output and not

    have the camera do a "white balance" before

    you get the bits. It may also have better

    dynamic range than the 8 bits/color

    tiff or jpeg output. Although with

    the small CCD, the signal-to-noise is lots

    worst than the 12 bits in the raw output.


    Has anybody seen dynamic range tests for this






    [Edited on 1-23-2002 by herbko]

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