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  1. #11
    Steve Smith's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    This made many things 5/6ths dimmer and you could see the fluctuations as a flicker.
    The whole of the UK is on 50Hz and this is to fast to see as a flicker.

    But we do have twice as much voltage as you!


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #12
    David A. Goldfarb's Avatar
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    Here's a straightforward explanation of the various units of light measurement--

    http://www.theledlight.com/lumens.html

    Some light meters can give measurements in Lux or footcandles, including the "Light Meter" app for the iPhone, if you happen to have one.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  3. #13
    Photo Engineer's Avatar
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    Why not just make a test strip or so to get the right exposure?

    PE

  4. #14

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    PE - I think Ray is trying to correlate historical infomation about materials with current ones.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  5. #15
    Photo Engineer's Avatar
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    I understand Kirk, but an exposure will allow him to do some back calculations or estimates at least. And the 50 hz power in Japan will throw everything off anyhow.

    PE

  6. #16
    lxdude's Avatar
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    Quote Originally Posted by Steve Smith View Post
    we do have twice as much voltage as you!

    Steve.
    Shocking!
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  7. #17
    Photo Engineer's Avatar
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    Quote Originally Posted by Steve Smith View Post
    The whole of the UK is on 50Hz and this is to fast to see as a flicker.

    But we do have twice as much voltage as you!


    Steve.
    Steve;

    When I was in Japan, I could see flicker! You are just used to it!

    PE

  8. #18

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    Quote Originally Posted by Photo Engineer View Post
    Why not just make a test strip or so to get the right exposure?

    PE - I think Ray is trying to correlate historical infomation about materials with current ones. Kirk

    I understand Kirk, but an exposure will allow him to do some back calculations or estimates at least. And the 50 hz power in Japan will throw everything off anyhow.

    PE
    Kirk is correct.

    This material is simply no longer available.

    Even if I had a sample, I am guessing the detailed exposure information provided at the time of it's manufacture would be more indicative of the fresh material than it's current speed would be.

    As far as the 50/60 thing I don't really understand.. maybe when you were here the power was not quite up to specs or something... In anycase, there is none noticed in my area, but I am not looking for it- besides- I stay in 60Hz areas... I wish I could say the same thing about the flush toilet!

  9. #19
    Photo Engineer's Avatar
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    I think a 60hz flush toilet or a 50hz flush toilet would be a real pain in the butt!

    I lived or visited both areas in Japan though and could see a difference in flicker and in brightness but that was long ago.

    PE

  10. #20
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    With incandescent bulbs, the flicker is so low that I would say it is impossible for human to see it. If you shoot a several frames in incandescent lighting with short shutter times (like 1/1000 s), they come up with almost exactly the same exposure. The filament has some heat capacity so it dims only very little in 10 milliseconds. And, the lower the lamp design voltage, the more heat capacity in filament. 12V halogens take literally a second to "shut down" completely!

    However, with fluorescent lights, some people (but very few) actually can see some flicker, or not see but rather "sense" it. It is not usual, but some people report tendency to headaches in strong fluorescent light. Which part of the cause is the high level of "strong" light and which part is due to flicker, it's hard to say. I have attached a series of (digital ) pictures of a fluorescent light I shot at 1/1000s to show the flicker.

    The frequency of the flicker is 100 Hz or 120 Hz because the light is generated on both half-cycles. As a comparison, the CRT television flicker is either 50 Hz or 60 Hz depending on the system, and film projection in the movies is 48 Hz or 72 Hz depending on the shutter type.
    Attached Thumbnails Attached Thumbnails loisteputki.jpg  

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