subject reflectivity measured TTL; based on this information, second (main) flash duration is calculated, and then strobe fires main flash quickly afterwards, only for the specified duration.

(Pre-flash TTL Auto Exposure Adjustment)

3)During exposure, strobe itself measures in real time

Using a light sensor in the strobe, subject reflectivity measured in real time, with strobe quenching at time of “proper” exposure. (External Auto Flash Exposure Adjustment)

For each of these automatic flash adjustment methods to work, besides a signal instructing the external strobe to fire, the various combinations of cameras (and master strobes) and external strobes must be compatible with each other’s signal transmission methods.

- In case of 1) above:

From Camera to External Strobe

Instruction to stop flash

- In case of 2) above:

From Camera to External Strobe

Instruction to stop flash; or,

 

 

Instruction for flash duration

 

External Strobe to Camera

External strobe information

- In case of 3) above:

From Camera to External Strobe

ISO Sensitivity information, and

 

 

Aperture Value information

As of December 2002, a majority of consumer digital cameras use Pre-Flash TTL Auto Exposure Adjustment. Unlike conventional 35mm film camera systems with the widely adopted Real Time TTL Auto Flash Adjustment, most current digicams cannot use such automatic exposure adjustment with external strobes. Likewise, except for some dedicated land strobes for certain camera brands, there are no external strobes yet available fully compatible of functioning with the various Pre-Flash TTL Auto Exposure Adjustment type cameras available. The main reasons are:

Because pre-flash specifications and protocol have not been standardized between the camera manufacturers.

The external strobe to camera signal transmission specifications have not been standardized between camera manufacturers, and the communication method used by most existing external strobes has not been adopted in most digital cameras.

Due to the lack of real time information from camera to strobe, digital cameras cannot automatically adjust exposure with external strobes. Therefore it is necessary for the external strobe itself, to a certain extent, independently execute automatic flash adjustment.

The D-180, as an External Auto Flash Exposure Adjustment type of strobe, and using an Advanced Cancel Circuit, is compatible with the vast majority of digital cameras using Pre-Flash TTL Auto Exposure Adjustment, and of course Real Time Auto Exposure Adjustment type cameras. Regardless of the camera type, automatic light adjustment is possible with the D-180 external

INON D-180 Manual

14

Version 1. October 4, 2003

 

Copyright 2002, 2003 by INON America, Inc.

All rights reserved.