Strobe eqivalent for No.5 flashbulb

Discussion in 'Large Format Cameras and Accessories' started by Lachlan Young, May 12, 2006.

  1. Lachlan Young

    Lachlan Young Member

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

    All help much appreciated,

    Lachlan
     
  2. MattCarey

    MattCarey Member

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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. DBP

    DBP Member

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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. Lachlan Young

    Lachlan Young Member

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    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. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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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.
     
  6. Pragmatist

    Pragmatist Member

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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.
     
  7. cdholden

    cdholden Member

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    tater salad

    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. Lachlan Young

    Lachlan Young Member

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    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. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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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.
     
  10. Jim Noel

    Jim Noel Member

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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.
     
  11. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I suspect the #5 is a little more powerful, but here's one across a 5-lane New York City street--

    [​IMG]

    Norman 200C pack, GVI auto strobe head, 5" plain reflector, Efke PL 100/Acufine (EI 200), 4x5" Tech V (image is about half the frame), Symmar 210/5.6 convertible at f:5.6, handheld, 1/15 sec. to catch a little motion.
     
  12. Lachlan Young

    Lachlan Young Member

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    They must have been seeing spots for hours afterwards...

    Thanks for the help,

    Lachlan
     
  13. df cardwell

    df cardwell Subscriber

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    Good one david

    Metz 60, Norman 200 = more or less a Press 5/25

    Or a 3, or even a lowly AG1

    .

    Think about how many flash pictures you'll make with your 4x5, and see how many flashbulbs you can find for free.

    The size of the bulb determines the size of the reflector.

    A little tilt-a-mite works great with 1s and 3s. A flashcube shooter is great with a 4x5.

    d
     
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  15. Pragmatist

    Pragmatist Member

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    Good question

    That's a good question, David. Next time I get a hankering to startle bystanders, I will compare the 135 Wolly with a 135 Fuji and see what comes up.

    I have read somewhere about the Norman conversion (LF or Graflex forums I think), but have never found any pictures or project description of the conversion. I have heard that the conversion is very easy, although it's a tight fit to make everything work. If anyone has some details of doing this, please post a source!
     
  16. egdinger

    egdinger Member

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  17. MattKing

    MattKing Subscriber

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    My Metz 60 series flashes (60CT1 and 60CT2) are great pieces of kit, but they certainly don't offer the open shadows that those wonderful salad plate size reflectors used with big flashbulbs do.

    Of course, they also recycle, rather than expire, so I am not complaining. :tongue:
     
  18. Donald Qualls

    Donald Qualls Member

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    Just my opinion, but I think most of the difference between the old flashbulb photos and those made with strobes is the reflector size. A photoflash in a 6" bowl acts like a light source six inches across -- the biggest reflector I've seen on a factory-built strobe was about two inches across, and most are smaller than that. That makes a strobe act more like a "point source" compared to the extended source of a large reflector -- which means the shadows cast by the flash have relatively hard, sharp edges compared to those made by a large reflector, giving an effect like the difference between a bright overcast and direct sun.

    That said, it's a lot cheaper to shoot a few #5 bulbs now and then than it is to get a strobe with the same guide number and remount it in a large reflector. I wonder, though, if you couldn't mount a common strobe backward, with a diffuser on the lens, and then reflect that light from a bowl reflector to get a light quality similar to a bulb in a big bowl? Or use a bounce flash firing upward into an diffuse bowl? Anything that will get the light to shine from a larger area instead of what amounts to a point from several feet away...
     
  19. MattKing

    MattKing Subscriber

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    Donald, as scary as it may seem, I think we think alike :tongue:

    I think that the Metz reflector card does some of this, but is still too diffused.

    Are Alien Bees a little bit like the old reflectors?
     
  20. df cardwell

    df cardwell Subscriber

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    no

    but a little tilt-a-mite, nikon, or darn near ANY bulb flash change things considerably.

    and if you have a real graflex variety flash, use the durn thing with BULBS
     
  21. Dan Fromm

    Dan Fromm Member

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    Lachlan, the least expensive, at today's prices for used equipment, huge potato masher with useful features is probably the Agfa 643 CS. According to a simple, naive test (set flash on tripod in a large room, set flash meter on another tripod 10' from the flash, fire flash, read meter) mine is about 1/2 stop below rated power at full output. Biggest drawback is that according to the user's manual at full power flash duration is 1/200.
     
  22. Pragmatist

    Pragmatist Member

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    This is exactly the point I was making earlier. Most of the Heiland and some of the graflex bowls are adjustable in the distance from the bowl to the bulb (horizontal movement) to concentrate the light according to distance. It is focusing a parabolic reflector. Other reflectors are fixed, and "maximized" for working at distances of up to 25'. This tends to seriously vignette the lighting circle at very short distances.

    Putting the flash head itself into the optical path of the reflector would create a "shadow" or blank spot in the central apex of the parabola. This is quite the opposite of the bulb/parabola effect, in that the projected light would be brighter at the periphery than in the center of the projected cone of light.

    This cone is the primary difference between the parabolic reflector, and the reflector units used in xenon flashes.
     
  23. benjiboy

    benjiboy Subscriber

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    Don't think so.

    If you are talking about a portable electronic flash Lachlan I don,t think the output from most powerful ones will give the same output as some of the smaller flashbulbs.
     
  24. egdinger

    egdinger Member

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    What about a sunpak 120 for the reflector look, though it is less powerful.
     
  25. Donald Qualls

    Donald Qualls Member

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    Dan, I don't see how a 1/200 flash is that big a deal if you're getting power comparable to a big magnesium bulb. Weegee used to shoot at 1/200 on the shutter, using the brightness of the bulb to let him freeze motion by clipping 5 ms out of the bulb's peak -- I don't recall seeing much motion blur in his flash images.

    If you have that kind of duration and a big reflector, what you've got is essentially just a fast flashbulb anyway, like a bright version of the SF gas-filled bulbs.

    You know, I've got a pair of old Strobonar flashes. They probably need new capacitors, and there's the issue of finding or making 510V batteries to run them (that's, what, 340 cells of carbon-zinc or alkaline chemistry -- maybe I could get them to run on $34 worth of those L76 button cells I can buy at 10 for a dollar?) -- but now I'm tempted to try mounting a diffuser and a big backward bowl on one and hanging it on the side of my Speed Graphic. I'd still have to use X synch, but I've got an X synch shutter I could mount on there...
     
  26. pandino

    pandino Member

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    I can't imagine a portable strobe that has the output or "look" of a #5/#25 magnesium bulb! I always get a kick out of how people respond to them. They can feel the heat 10' away and see spots for a few minutes afterwards. My 3-yr old points to the ceiling and says, "Look! Sun!" after being photographed with one.

    If you're planning to use a strobe on the Speed Graphic, you'll be limited as to which shutter speeds you can use. I would suggest just locating some bulbs (preferably FP26 if using the Speed's focal plane shutter) and using the real thing. If you can't find a good cheap supply of the 25/26's, then you can always get a M3/M2-to-#5 adapter and use the smaller, cheaper bulbs. They still have a pretty high GN. I typically have to stop down to at least f/16 when using M3's in the house.

    Your actual GN will depend on the shutter speed, film speed, reflector size, finish and position. The Graphic 5" reflectors typically have Tele and Normal positions. The GN for the respective reflector size will be on the bulb packaging.