Manual Mode & Flash Exposure

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Thanks to NK Guy's documentaiton, I know how the various picture taking modes affect or are affected by the flash.

I use an Elan 7 and Speedlite 550 EX.

If I am concerned about depth of field (say of a group of people in a party picture) and I need better than f4 at 60 (which is what the camera deploys in program mode with speedlite attached), and I switch to manual and dial in f8 at 60--the camera tells me the shot will be very underexposed. I take the picture anyway. The Speedlite's exposure confirmation button glows green, telling me that the shot has been properly exposed. Is this true?

Bear in mind that I am using partial metering set to the active focusing point (in this case, hovering over a person's face). If in manual mode the meter is considering the background/ambient light (as if there is no flash attached)--I understand, but just how much apparent underexposure is the Speedlite capable of compensating for?

Can I shoot at 60 and very narrow apertures (f11, f16) in manual mode and trust the Speedlite to make up the difference, 3-5 stops?

Thanks for any insights.

-- Preston Merchant (merchant@speakeasy.org), April 11, 2002

Answers

"The Speedlite's exposure confirmation button glows green, telling me that the shot has been properly exposed. Is this true? "

Works for me. Your properly exposed film should prove it.

"just how much apparent underexposure is the Speedlite capable of compensating for?"

The effective range of the flash has nothing to do with ambient light. The 3 variables in flash exposure are (a) flash output, (2) distance to subject and (3)aperture. It could be pitch black in the room, and the flash could provide proper exposure

"Can I shoot at 60 and very narrow apertures (f11, f16) in manual mode and trust the Speedlite to make up the difference, 3-5 stops?"

Basic calculation: 550EX Guide Number /in feet/@50mm setting/ISO 100 is about 130. For f16, 130 /16 = 8.13 foot maximum range. For ISO 400 film, the maximum range doubles to about 16 feet.

-- kenneth katz (socks@bestweb.net), April 11, 2002.


Can I shoot at 60 and very narrow apertures (f11, f16) in manual mode and trust the Speedlite to make up the difference, 3-5 stops?

The actual Guide Number can vary with the zoomed angle of flash coverage, the charge in the condensor, the shutter speed, and the reflectance of the walls and ceiling around the camera.

But why guess? The Elan 7E can check for adequate power from the 550EX by using Flash Exposure Lock. Push [*] and if you see a blinking flash symbol, back off the aperture until the blinking stops.

-- Julian Loke (elan7e-owner@yahoogroups.com), April 12, 2002.


Thanks, guys, for very helpful info.

-- Preston Merchant (merchant@speakeasy.org), April 12, 2002.

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