What exposure value is taken into account for Elan IIE "automatic" fill flash reduction?

Metered with built-in light meter? Or calculated from the current aperture and shutter speed settings? Or something menitoned above, but corrected for the current film E.I.?

-- Nikita Belenki (photo@kits.net), May 26, 1999

Answers

There is a very good & detailed explanation of exactly how the Elan II flash system operates on http://bobatkins.photo.net/info/faq30/flashfaq.htm by Chuck Westfall who works for Canon.

-- Norman Chappell (nchappell@aul.ibm.com), June 08, 1999.

Norman,

I have already read this text many times. Maybe I am stupid, but I haven't managed to find the answer on my quesion in it, so as you are probably much smarter than me, could you please answer to my question? What does "ambient light" (measured in EV) exactly mean there?

-- Nikita Belenki (photo@kits.net), June 09, 1999.

Nikita,

I have an ElanIIe. My understanding is that the automatic flash reduction is up to a maximum of 2 stops. So, it could be less in some cases.

The Elan has ETTL capability, which is a new form of autoflash, and has been called the best to date (by Popular PHotography) and some Canon pro users. Here's how it works:

First, to answer your later question: AMBIENT LIGHT is the light in the environment in which you are shooting-- the sun, lamps, flourescents etc., VERSUS the light YOU bring with you to the shoot, such as your flash.

When equipped with an EX flash (380EX, 550EX etc.), the ElanIIe determines autoflash exposure as follows:

1. the EX flash fires a pre-flash. This light returns to the camera and is measured to determine the best power setting (such as fill reduction) by comparing it to the AMBIENT metering (the light measurement of the light in the environment).

The camera uses the Elan's most sophisticated metering (Evaluative for ambient) to do this; along with a flash sensor located up near the viewfinder. The two readings are compared and the camera works out the optimum COMBINATION of light from the flash and light from the environment to produce the most natural looking flash shots possible. Once determined, in a period of 4 microseconds including all these steps, the camera sets the flash and itself accordingly.

ETTL's method is different. The last generation, ATTL, used the preflash only to measure distance, and the earlier TTL had no preflash but measured off the film plane.

Make sense? If not, please feel free to email me. Flash can be very complicated; I find it so, though I'm starting to catch on a bit.

Regards, Roy

-- roy kekewich (roykekewich@yahoo.com), January 28, 2000.