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Old May 25, 2003, 7:35 AM   #1
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Default decreasing flash output

hey, i have a quite exteral powerful flash
and i was wondering what do you do to soften it up

i've read about film,tape, but what do you think is best?

thanks

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Old May 25, 2003, 11:03 AM   #2
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Hi,

Don't laugh but I tape tissue's before the flash if I need less power.

Greetings,
Frank
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Old May 25, 2003, 11:34 PM   #3
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Default Re: decreasing flash output

Quote:
Originally Posted by davebaird
hey, i have a quite exteral powerful flash
and i was wondering what do you do to soften it up
It depends. Some powerful flashes may have a power ratio feature for reducing its power in automatic and/or manual mode. The manual of your flash may discussion how to use this feature. Some cameras such as Nikon's Coolpix cameras may have an option "Variable Power" that permits a user to tune down the (internal and external) flash output. Check your manual for the details.

Quote:
Originally Posted by davebaird
i've read about film,tape, but what do you think is best?
A processed film may be too much. 3M tape or tracing paper may do the work. However, this may or may not work well. If your camera reads flash exposure from the lens, it will simply ask the flash to send more power until the flash reaches its output limit. This, of course, depends on how the camera measures the flash illumination, and, hence, I cannot answer this question fully. You might also try to reduce the ISO speed to "consume" some extra power.

CK
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Old May 26, 2003, 6:29 AM   #4
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You might want to try this: http://www.lumiquest.com/

I especially recommend their inexpensive and flexible Promax system, which'll come with everything you might need to reconfigure your flash head! The system is so flexible that I can move it between different brands of cameras... 8) 8) 8) (and fold flat in a pouch when not in use!)
http://www.lumiquest.com/lq932.htm
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Old May 27, 2003, 12:08 PM   #5
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Default Re: decreasing flash output

Quote:
Originally Posted by davebaird
hey, i have a quite exteral powerful flash
and i was wondering what do you do to soften it up

i've read about film,tape, but what do you think is best?

thanks

www.davidbaird.myby.co.uk
Decreasing flash output and softening the light are two different things. To soften a light source you need to make it bigger. Tiny point source = harsh. Big softbox, reflector card, umbrella = soft. If you want soft a reflector like the wise NHL suggested would work well.

Merely reducing output doesn't make your light softer. Doesn't matter if you cover it with cloth or tissue the source size will still be the same and at best you'll get a tiny diffusion effect. Changing the ratio of flash to ambient may make the harshness less apparent but doesn't soften it.
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Old May 28, 2003, 9:55 AM   #6
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There are several ways to reduce the power of the flash, for TTL mode, the camera make the adjustment for correct exposure, you can futher reduce the flash output by using the exposure compensation button control or other control button provided by your camera. For manual flash, most flashes have the power ratio control, you can reduce its power by 1/4, 1/2, 3/4 and so on. Using the flash acessories to soften the light does not neccesary give you the same effects but will reduce the effective range of the flash and give you wide coverage angle.
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Old Jun 9, 2003, 8:43 AM   #7
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If reducing the flash output is really what you want to do, ask about Neutral Densisty gelatine filter at your pro photo shop. Whatever you put in front of the head mustn't change the light colour temperature else colour balance will be upset.

ND is effectively sold in calibrated densities, so you can have a piece for 3/4, 1/2, 1/4 light output etc.

I sympathise with your problem. Some guns have manual switchable power control others don't. If you are using a gun with Auto settings, you can fool it by setting lower f stop and or higher ASA to get less light per flash.
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Old Jun 9, 2003, 9:56 AM   #8
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Guys

Decreasing the output is not a solution... you're only lowering the exposure, ie darkerning the picture (or the camera will compensate by opening up the aperture)! The fact of the matter is you want to expand the point source to decrease the harness of the flash! The only way to accomplish this is to diffuse and soften up by expanding the light source while keeping the exposure value constant!

ie
Quote:
Tiny point source = harsh. Big softbox, reflector card, umbrella = soft.
ND is worst since it'll increase the recycle time by forcing the flash to output even more, and increase the harness even further.
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Old Jun 9, 2003, 10:36 AM   #9
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Quote:
ND is worst since it'll increase the recycle time by forcing the flash to output even more, and increase the harness even further
Only if the flash is used in Auto sensing mode! Not if its output is manual but fixed to maximum. In which case you're stuck, you can't control the output, yes you know you're always going to get the biggest bang, slower re-charge but you can't change that. I don't think the camera compensates by opening up the aperture during external flash, I've always fixed the aperture in manual, and told the gun what it's set to and the ASA. Can it work out exposure in 1/1000th second or less? More likely it sets max aperture on auto for the available light, and in internal Auto winds the flash output down from the auto focus distance setting.

NHL has a point that if it's harshness thats the prob, (Oh how I wish more light was a prob!) Have you tried bouncing?

Over on DPR they're raving about Pringle lids for white bal set up, I suppose a couple of those lids on the gun would soften things a bit!

I think the original question is about softening. I've had a number of flash shots where the subject is to hot, faces burned out and a couple of metres away, total black. Some of this I put down to lack of digi-latitude. But since I've been trying bounce with a bigger external flash, I've seen better results.
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Old Jul 10, 2003, 11:29 AM   #10
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Padeye is right.

To soften the flash glare the light source must be made larger. Either get the flash closer and compensate for the more powerful light output (sometime I cover the flash partially with my finger) or get something like a large diffuser to bounce and relect the light into a wider area.
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