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  1. #1
    dmr
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    Bare-bulb flash exposure advice, please ...

    Hopefully we have some hardcore strobe lighting jocks here who can help out on this. I've asked on a couple other boards and gotten some responses, but nothing authoritative. I'm hoping for something more than "bracket" or "take a test roll", from somebody who really knows lighting.

    Next month I'm going to be shooting some interior shots in a rather unusual venue. Groups of people in meeting and dining rooms in a smaller restored "boutique" hotel, with dark wood paneling and darker earth tones. Ceiling, IIRC is maybe an ecru or a dark eggshell at the lightest, quite warmish, IIRC, so bounce flash will probably not be an option. Available light is poor, mixed, and quite warm.

    Here's the problem. To get these shots I'm probably going to have to use the Sigma 18mm ultrawide. (non fisheye)

    I have two flash units, a Vivitar 2600, which is probably out of the question. Then I have the hand-me-down resurrected Sunpak 120 flame-thrower. I know it won't light the scene with the reflector, even at the so-called wide-angle position.

    I can do it bare-bulb, no reflector, either aiming the bulb upward or pointed forward.

    The problem is, I have no clue as to how to expose for such a situation.

    Can auto mode be depended upon in a situation like this? Or should I use manual and do guide numbers? If I do guide numbers, should I try to adjust for the 360 degree coverage of the bulb?

    Yes, I looked at TFM, and it didn't really say much about bare bulb mode except that you can do it.

    Anybody shot a bare bulb unit in a similar situation?

    TIA!

  2. #2
    segedi's Avatar
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    I'm guessing you are shooting 35mm but what camera and film do you intend to use? Can you trigger more than one flash? Shooting on tripod? How high is the ceiling? Will people be in the photos? Lighting is poor but is it flat/even? Main light sources?
    Do you have an external meter and ability to meter flash/ambient mix?
    -----------------------

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  3. #3

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    I'd reconsider using a bare bulb. Shooting groups (it would help if you could say how large the groups are expected to be) with a bare bulb is going to give you harsh, deep, shadows and glaring highlights, more so if the walls and ceilings are relatively dark... Consequently, depending on how you set up the shot, you may find that the shadow cast by one group member will obscure another and that the fall off from the foremost subject to the furthest will be rapid. In short, bare bulb will be unflattering to your subjects.

    If you can't get hold of brollies and more powerful strobes, I'd suggest you fire both flashes (with reflectors) backwards at a larger reflector, behind and above you, to get the required spread. I use an old sheet of Tyvek that I keep in my kit for this, if I haven't got my fold out reflectors with me. However, guide numbers won't help you with this set up, you'll need a flash meter. I wouldn't risk doing this type of thing without one, especially if I was shooting film.

    However you go about it, you need to diffuse/reflect those lights to soften the output...

    Regards
    Jerry

  4. #4
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    Barebulb is still going to give you a cast from off colored walls. How bad it will be is impossible to say without seeing the place.
    Like segedi suggests, is it possible to fire off camera with a radio trigger?

    These situations are tough and if you have to go on camera flash for key I'd use a bracket and get the light as far off axis as possibleand use some type of diffuser.

    As to exposure, thats just a question of auto mode or getting REAL comfy using guide numbers on manual mode.
    If you use the same focal length lens throughout it gets east to judge distance.

    Why an 18mm? I know the place is probably tight but it wont exactly flatter guests and good luck if anyone ends up in the corner of the frame.

  5. #5
    segedi's Avatar
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    Couple more questions... Intent of the photos, is it the groups or the meeting space itself? Angle, will you use a ladder?
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  6. #6

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    I've shot in similarly tight situations on 35mm, using nothing wider than a 28mm lens (when I worked for my college newspaper, 28mm was the widest lens available to me). 18mm may be far too wide for people shots.

    As far as the lighting goes, if on-camera flash is your only option, diffusion on the Sunpak 120J with the reflector is a good bet, as is a bracket. I've also used a Stofen-style diffuser on Nikon SB-16 or Vivitar 283 flashes. I used to have a Sunpak 120J... now I have a floodlight reflector that I spray-painted powder-coated silver, and cut a rectangular hole in for the SB-16. This is fairly soft.

    Is there any chance of getting into the place in advance and doing some tests, especially if you can at least borrow a flash meter?

  7. #7
    dmr
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    Quote Originally Posted by segedi View Post
    I'm guessing you are shooting 35mm but what camera and film do you intend to use?
    A Real Camera<tm> of course! Seriously, Pentax K1000, Sigma 18mm rectilinear ultrawide, probably plain vanilla Fuji 200 C41 color film. Not TTL auto exposure, but auto via the Sunpak's "eye" in the unit.

    Can you trigger more than one flash? Shooting on tripod?
    I won't be able to do anything fancy at all, just hand held. I do have the stroboframe, so the flash will be somewhat above the normal hot shoe position.

    I'm also guessing that I'll have 5 minutes or so to get everybody together, posed, and hold their attention long enough to get enough shots before they start grumbling and wander off. This group is the type who will groan when we pose them, but will go "ooooohhh, can I get a copy!" when I show the prints.

    How high is the ceiling?
    IIRC, 10 or 12 feet. Higher than the usual home of office ceiling.

    Will people be in the photos?
    Of course, that's the whole point!

    Lighting is poor but is it flat/even? Main light sources?
    Last time I was there, it was a mix of incandescent (might be those curly-que fluorescent) and those small reflector type highlight lights hitting artwork on the walls and such. My guess is that if I were shooting candids in available light with the RF, 800 film, 1/30, and close to wide open on the lens would be in the ballpark. In other words, I don't think the ambient light is enough to really consider here.

    Do you have an external meter and ability to meter flash/ambient mix?
    No flash meter. I could meter the ambient but I'm sure it will be at least a number of stops down from what the flash will do.

    I'm not after perfection here. I certainly don't want to let what is ideal stand in the way of what is good.

    As for the expectation of quality here, if I can do "good snapshot quality" or better, it's a winner! Something better than cam phone or typical P&S digicam quality will be fine. They were tickled pink when I said I was confident that I could get some good shots of them in there, particularly after our resident know-it-all DSLR jock said it was impossible. (Jees! I hope he doesn't read this board!) {blush}

    Anyway, a few who have replied have confidently said "Trust The Force" and trust the auto-exposure and not futz around with computing guide numbers and such. This does make sense now that I think about it.

    Thanks to all for the quick replies on this. I got more responses here than anywhere else.

  8. #8

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    b+h and other photo retailers sell screw-in slave flash bulbs
    so you can replace a normal 1/4" socket c/f or incandescent bulb
    with a bright flash/strobe that will slave to the flash you have on your camera.

    it might be worth considering asking the folks that work at the place you want to photograph
    if you can replace a few of their bulbs with yours. it will help you a lot!
    i am not familiar with your flash but i have a feeling it won't really be bright enough to light a who room
    so you will see more than "hot" and shadows. i used to shoot barebulb with
    a lumedyne pretty often, but it threw off 200-400 WS of light, probably a bit more
    than yours can do ...
    something to consider is to use an elastic and a white card and tape it to the flash you have and shoot straight up.
    the card will bounce the light forward and you will be able to bounce the light off the ceiling down ...
    but 8-10' ceilings needs a lot of light ...

    if you can go after hours and do a test roll you probably will be better for it ... shooting
    something like this on the fly can be "fun"

    good luck !
    john
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  9. #9
    benjiboy's Avatar
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    I suggest you invest in a Sto-Fen Omni bounce Diffuser http://www.stofen.com/index.asp it even covers my 17mm wide angle lens and produces soft shadows when shooting groups, it is always used bounced at 45 degrees not used directly, and allows the flash to bounce off the ceiling and throws it forward at the same time and can be used with auto computer flash and gives correct exposure, I use one with a Metz 45 CL5 and a Vivitar 285 and it works for me.
    Last edited by benjiboy; 03-21-2011 at 11:43 AM. Click to view previous post history.
    Ben

  10. #10

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    The auto flash will grossly overexpose your subject with dark paneled walls, it ain't pretty. even with umbrellas you're going to need a flash meter OR do some test shots to give you exposure at set distances.
    Heavily sedated for your protection.

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