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  1. #1
    Lachlan Young's Avatar
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    Strobe eqivalent for No.5 flashbulb

    Can anyone recommend an electronic flashgun of equivalent output to the GE#(?) No.5 flashbulb?

    All help much appreciated,

    Lachlan

  2. #2
    MattCarey's Avatar
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    Hello,

    you will never find an equivalent in the time of output (I believe). A flash puts out light for a long time relative to an electronic flash. This makes the guide numbers dependent on shutter time. The total flash power is much higher, typically, in bulbs over electronic flashes.

    Matt

  3. #3
    DBP
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    If my 1946 Lawrence slide rule is correct, the guide number for a No 5 with ASA 100 film with an average reflector and shutter speed around 1/125 is about 250. If I use ASA 50, which probably closer to ISO 100 due to the safety margin in the original standard, the guide number comes out around 175. With a slower shutter speed, the GNs are 295 and 210 respectively. Some of the big 'potato masher' flashes can come close to 200 at full power. Maybe someone else on the forum can suggest a few choices.

  4. #4
    Lachlan Young's Avatar
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    Quote Originally Posted by DBP
    If my 1946 Lawrence slide rule is correct, the guide number for a No 5 with ASA 100 film with an average reflector and shutter speed around 1/125 is about 250. If I use ASA 50, which probably closer to ISO 100 due to the safety margin in the original standard, the guide number comes out around 175. With a slower shutter speed, the GNs are 295 and 210 respectively. Some of the big 'potato masher' flashes can come close to 200 at full power. Maybe someone else on the forum can suggest a few choices.
    I was thnking about the Norman 200c style of unit as used by David A. Goldfarb but I don't know what its guide number is. Alternatively, what is the power output of a Graflex strobe?

    Thanks,

    Lachlan

  5. #5
    David A. Goldfarb's Avatar
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    The guide number of a Norman, Lumedyne, Quantum, or similar barebulb unit depends on the reflector or diffuser in place. Based on my tests (rather than manufacturer's specs, which tend to be a little optimistic) with my Norman portables I get these maximum guide numbers (200 W-s) in feet at EI 100--

    Reflector 2D (basic 5" reflector)--160

    Barebulb in a small room with light colored walls--80

    Photoflex XS Light Dome (12x16" softbox) or Norman 5" white reflector with opal glass diffuser--about 90

    Norman 10" telephoto reflector with optical spacer--320 (but the coverage is only suitable for long lenses)

    Norman makes a portable 400 W-s pack as well (400B), that has twice the output as the 200B and 200C, so it should produce a GN of 220 with the basic 5" reflector.
    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

  6. #6
    Pragmatist's Avatar
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    Ain't no match...

    The old Honeywell potato mashers (Strobonars) usually have a GN somewhere around 100 @ ISO 100.

    It is a combination of things that give bulbs a distinctly different look from xenon. Aside from the sheer output, there is how the bulb "burns" When you fire a bulb, the ignition starts in the center, and goes outward. This means that the most intense light output is in the center of the projected circle, decreasing outward. As a result, the central parts of an illuminated scene are "hotter", with a decreasing fallout toward the edges.

    Second is the reflector itself. I have a Heiland unit, and use #25 Press with it. The Graflex are similar. The reflector bowl is a special parabolic design, and is adjustable to capture the apex of the bulb flashoff and project it forward, depending on the distance of the camera from the subject. This couples up with the "center out" illumination characteristic of the bulb itself. These factors are what lend the "Wegee" or "Hollywood" look to larger flashbulb photography.

    Xenons scatter their light in a generally uniform path, and the reflectors they reside in are fixed in a way to maximize the output lumens across a broad range of distances. Various diffusers and concentrators are available, but they do not exactly mimic the effect of a bulb flash. It might be possible to make a "vignette" type mask of screed material to mimic the edge falloff, but I still dont think that it will match the unique character of the real thing.
    Patrick

    something witty and profound needs to be inserted here...

  7. #7
    cdholden's Avatar
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    tater salad

    Quote Originally Posted by DBP
    Some of the big 'potato masher' flashes can come close to 200 at full power. Maybe someone else on the forum can suggest a few choices.
    My old Metz 60 CT4 is rated at 198, IIRC. It's a heavy beast to lug around in the field, but great source of power. I've used it a few times in bird photography. Great for when you need to "reach out and touch someone".
    Chris

  8. #8
    Lachlan Young's Avatar
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    Quote Originally Posted by Pragmatist
    It is a combination of things that give bulbs a distinctly different look from xenon. Aside from the sheer output, there is how the bulb "burns" When you fire a bulb, the ignition starts in the center, and goes outward. This means that the most intense light output is in the center of the projected circle, decreasing outward. As a result, the central parts of an illuminated scene are "hotter", with a decreasing fallout toward the edges.

    Second is the reflector itself. I have a Heiland unit, and use #25 Press with it. The Graflex are similar. The reflector bowl is a special parabolic design, and is adjustable to capture the apex of the bulb flashoff and project it forward, depending on the distance of the camera from the subject. This couples up with the "center out" illumination characteristic of the bulb itself. These factors are what lend the "Wegee" or "Hollywood" look to larger flashbulb photography.

    Xenons scatter their light in a generally uniform path, and the reflectors they reside in are fixed in a way to maximize the output lumens across a broad range of distances. Various diffusers and concentrators are available, but they do not exactly mimic the effect of a bulb flash. It might be possible to make a "vignette" type mask of screed material to mimic the edge falloff, but I still dont think that it will match the unique character of the real thing.
    Thanks for the info - my Speed graphic, if I was so minded, could be fitted with a Heiland flash on one side and a Graflex flash on the other! Anyway, what size of reflector should I try and get hold of for a Heiland flashgun?

    All help much appreciated,

    Lachlan

  9. #9
    David A. Goldfarb's Avatar
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    If you want the effect of the old reflector with the convenience of electronic flash, I've seen Graflex flashguns with the guts of a Norman LH-2 head stuffed in the battery case and a flashtube socket in place of the old bulb socket. It looks like a fairly straightforward modification. Not sure what guide number you get with that.

    As far as the falloff issue goes in the Weegee days, I wonder how much of that was due to the fact that they were using 135mm and 127mm lenses that just barely covered the format and might have been on the wide side for the flash reflector, and how much was the flashbulb pattern.
    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

  10. #10
    Jim Noel's Avatar
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    I don't believe a handheld strobe has yet been made which matches the output of a #5.
    In the 1940's we used to use them at high school football games. They were powerful enough to light up the faces of the crowd on the opposite side of the field. I have never seen this happen with an on camera strobe. These are the reasons I still have some #5 GE and Sylvania bulbs.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

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