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Re: [OM] Softening F280 flash

Subject: Re: [OM] Softening F280 flash
From: "John A. Lind" <jlind@xxxxxxxxxxxx>
Date: Sat, 31 Aug 2002 17:38:48 -0500
At 15:21 8/31/02, Pete wrote:

Thanks for the details!

You're welcome. I've gone through experimenting with a number of diffusion methods to soften direct flash. A couple of tips I should have included:

Lens Hood:
Using one is always recommended, even if it's a modest one. It becomes much more important for preventing flare when using any diffusion device that has its front farther forward then the lens front. Applicable to using protruding flat panel softboxes such as the LumiQuest and a *must* if using something like the Sto-Fen Omni-Bounce. I also have a couple of brackets that mount the flash farther forward than the integral hot shoe: a G-15 Metz grip and a Newton camera rotating bracket. The Metz G-16 grip which I also have isn't as severe, but still mounts the flash farther forward than the hot shoe. Even without any diffusion, the front of the flash can end up farther forward than the a lens front, especially with the 50mm standards which are among the physically shorter lenses. I imagine the 40/2 pancake has even greater risk.

Normal-Auto versus TTL-Auto (not an F280 problem, but can affect others):
Not a problem with your F280 as it doesn't have a Normal-Auto mode, but if you have a flash that does (now or in the future), and use it in Normal-Auto, there's a risk of exposure error. Devices such as the Sto-Fen Omni-Bounce and similar home-brewed ones made from plastic milk cartons can put direct flash illumination onto the "Normal-Auto" sensor built into the flash. This can result in gross underexposure. Been there, done that using a Sto-Fen on a Metz with an OM-1n and a couple other cameras that don't have TTL-Auto when I forgot to shield the sensor. There have been one or two threads on this list in the past about the home-brewed ones doing this. The solution is either tilting the head upward slightly (the Metz head tilts) or using some other method to shield the sensor from direct illumination by the diffuser. No problem in TTL-Auto or Manual modes which don't use the sensor. Softboxes such as the LumiQuest and similar ones can create an opposite overexposure problem by partially blocking the view of a flash sensor. This is very dependent on flash design and where the sensor is located. It's the reason the larger Lumiquest SoftBox has a triangular notch in the bottom instead of being a rectangular panel. This allows it to work with almost all flash units; there are a few with which it still blocks the sensor..

BTW, the desire to use diffusion devices is the major reason I've gradually been moving toward more powerful flash units in the 120 to 170 GN range (in feet; 36 - 50 in meters). These punch out enough light that loss from diffusion devices doesn't limit working distance as much as with a single T-32 or F280. This is the practical flash power limit for integral flash batteries. More powerful ones are best used with a separate battery slab worn on a belt or shoulder strap, even if there's a provision for internal batteries.

-- John


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