low powered flash?

Discussion in 'Lighting' started by kadath, Feb 17, 2010.

  1. kadath

    kadath Member

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    Hi,

    I'm looking for a low powered flash for my leicaflex sl. The situations I'd be using it in are ISO 800, f2, shutter about 1/30. Distance will be about 1 or 2m. So just a tiny bit for fill.

    I only have the smallest metz, which is still way too powerful (it only goes down to ISO 100, f 2.8 on auto).

    thanks,
    david
     
  2. jnanian

    jnanian Advertiser Advertiser

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    the lumiquest mini / or micro softbox for on camera flash might
    cut your light down enough enough. i used something like this
    and it worked OK but ate too much of my light, so who knows it might be what you are looking for ?

    http://www.bhphotovideo.com/c/product/544395-REG/LumiQuest_LQ_108_Mini_SoftBox_for.html

    a few other options:
    a sunpack might let you dail down to 1/8 power i think mine does ...

    if you have the $$$ and you think you will use it .. look for a lumedye 244 (with a battery).
    also look for what they refer to as the "hama" / handle unit.
    it allows you to dial the output down to about 2ws.
    if 2ws is still too muchlight, you can also get a globe for it, or "the tupperware lid" to diffuse you light more ...

    there was one of these lumidynes (here) in the classifieds a while back

    have fun!
    john
     
  3. mgb74

    mgb74 Subscriber

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    I keep a few old manual flashes around for this purpose (also for triggering slave flash). Typically use 1 or 2 AA batteries.

    Mat Acetate will help reduce light intensity and soften. Can fold over for varying levels. But need to test with film or flash meter.


     
  4. kadath

    kadath Member

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    thanks, the softbox seems to only reduce the light by a stop, and I seem to be 4 stops over. Also, since the auto flash sensor is at the bottom of the unit, won't it bypass any light reduction on the flash itself (since it is a reflected reading)? Would this occur with mat acetate?
     
  5. Mike Wilde

    Mike Wilde Member

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    re-direct some of the flash output directly to the flash auto eye, and you will get the flash quenched as fast as the electronics can shut it down.

    I have used some flexible plastic 'lite pipe' found in some of my son's lego sets as such a pipe, and held it in place in the corner of the flash window with some white colured 'blu tac' sticky papers onto the wall stuff.

    Like the mat acetate, there are theatre lighting/cinema lighting gels made (Lee and Rosco are the big names here) with neutral density build in to a calibrated level, -1 stop, -2 stop, -3 stop that can be put in the lite pipe 'light circuit' to get more light out of the flash.
     
  6. John Koehrer

    John Koehrer Subscriber

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    You would want to set the ISO up for less light at close range. Shorter duration flash.
    Vivitar 283 with the Vari-power module allows you to cut exposure by 5 stops. The 285 has this feature built-in but I don't know how many stops it will adjust.
    Metz also has out put control on several flash units
     
  7. mgb74

    mgb74 Subscriber

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    If I understand correctly, you want to use your "tiny" flash as fill for available light. In other words, primary light source is sunlight or room light, and your using the one flash for fill.

    If an automatic flash, anything over the light source will not have an effect, since the auto feature of the flash will compensate.

    I think what you can do is meter based on available light, choose an f/stop that corresponds to a shutter speed at or slower than your sync speed, and set your flash to an ASA/ISO 2 to 4 times higher than your film speed. You are, in a sense, fooling your flash to underexpose by 1 to 2 stops. You can still use the mat acetate, but it is for diffusion, not light reduction.



     
  8. 2F/2F

    2F/2F Member

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    I would not buy a new flash for this. Diffusion will eat up some light, if you want to use diffusion. So will ND. It would be ideal if you had a flash meter, so you know just how much of this stuff to add to get what you want. It would also be ideal if you could take the flash off the camera, but I don't know if the situation would allow that.
     
  9. jp498

    jp498 Member

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    I have used the silvered anti-static bags that computing parts come in for ND, and kept it on the flash with scotch tape for diffusion. Works great. A well place finger over the flash lens works too but can cause a color cast with color photography.
     
  10. kadath

    kadath Member

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    I could use diffusion, but I still don't get how that will reduce the light on an automatic flash. If I reduced the light by two stops say, won't the flash compensate by shooting until it reads the full light value? I'm guessing this would be on manual, but then I think it will would be an 8 stop difference (guide number 20), and I have no idea how to diffuse that much light. I guess what Mike was saying was the most likely to work, by redirecting some of the light directly to the sensor. For the manual flashes, like the Vivitar, they're at a guide number of 120, so a 5 stop reduction (in manual mode) in power output would still not reduce the light enough.

    And the ISO on the vivitar only goes to 400 doesn't it? Are there any that go to 1600-3200?

    The purpose of all this is occasionally when I'm using colour film under mixed lighting, I like to get a touch of daylight balanced fill in the foreground. My current (poor man's) solution is just to shoot black and white.
     
  11. mgb74

    mgb74 Subscriber

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    Reducing the light itself (via ND or diffusion) doesn't change the light output as controlled by the auto sensor. As you say, the sensor will compensate by allowing the flash tube to deliver more light.

    Directing more light directly to the sensor will "fool" it into thinking the subject has enough light and will cause the flash tube to deliver less light.

    Changing the ISO will also "fool" the sensor into thinking the subject has enough light for the film speed it "thinks" you're using. This, as you suggest, only works if you can dial in a faster ISO than the film you're actually using.


    I took a quick look and all my really small flashes do max out at 400 on the dial. My Vivitar 3500 does go up to 800.
     
  12. MattKing

    MattKing Subscriber

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    Changing the ISO on an automatic flash doesn't have any effect on the light output. All it does is change the aperture that the flash tells the photographer to set on the camera.

    If the auto flash has more than one range (eg a "Red" range, a "Blue" range and a "Yellow" range) than the choice of range will affect the light output. If you choose the range that suggests the largest aperture, but shoot at a smaller aperture, you will get less light output than would normally be needed for full illumination.

    A heavily diffused and bounced flash on manual is probably the best bet - with a flash meter.

    Matt
     
  13. 2F/2F

    2F/2F Member

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    There is no point in using a fully automatic flash for fill light, unless is can be specifically set to do such. The flash exposure will always be wrong unless it is controlled manually, or with an auto fill light setting.

    You are better off with a hot lamp filtered to match the main light if all you have is an automatic flash.
     
  14. John Koehrer

    John Koehrer Subscriber

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    Although the Vivitar ISO maxes out at 400, if you have the VP-1 for the 283 you can still reduce the output by 5 f-stops.
    The 285 has the VP module built in.
     
  15. kadath

    kadath Member

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    I've just found information on the leica sf24d, which seems like the most versatile flash I've seen, with all apertures from f2-11, ISO 25-800 and +/-3 f-stops, all in automatic mode. Anyone used this? I was considering selling some of my old canon eos stuff, so I might be able to afford it 2nd hand.
     
  16. Denis R

    Denis R Member

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    flash

    you said the C-word, I'll say the N-word :wink:

    1. Nikon SB-11 ISO 25 - 800 f 2 - 32 max power gn 120 @ iso 100
    max power only in manual, adjustable power in auto. with sensor unit su-2

    2. Sunpak 522 ISO 25 - 1600 f 2.8 - 22 max power gn 120 @ iso 100
    max power to 1/64 in manual, adjustable in auto.

    both are handle mount bouncers

    seems it's easier to get less light from a large flash unit than more from a small one