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strobe itself.
To determine your camera's automatic light adjustment type please refer to your camera manual,
and Page 18, "Items to confirm before using D-180".
Flash Adjustment Type Naming Conventions used in this Manual:
Real Time TTL Auto Exposure Adjustment
Real Time Auto Exposure Adjustment
Pre-flash TTL Auto Exposure Adjustment
External Auto Flash Exposure Adjustment (with pre-flash)
External Auto Flash Exposure Adjustment (without pre-flash) R-S
Manual Flash Exposure Adjustment (with pre-flash)
Manual Flash Exposure Adjustment (without pre-flash)
Reference No. 2
TTL stands for Through The Lens; that is, light which passes through the camera lens.
In order to obtain proper exposure, of various methods to measure exposure amount, light passing
through the lens and directly striking the light sensitive medium/device (silver halide film, image
sensor(CCD) etc.) is metered directly; or, metered indirectly if it is reflected off the light sensitive
medium/device.
An external strobe using these TTL metering methods of automatic light control is called a "TTL
Strobe" and an external slave strobe set to synchronize with the master strobe's flash duration is
called a "TTL Slave Strobe".
For the purposes of this Manual, we distinguish between two types of TTL light adjustment, both
of which are common in current digital cameras.
Real Time TTL Auto Exposure Adjustment
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Pre-flash TTL Auto Exposure Adjustment
Real Time TTL Auto Exposure is when the image is being taken (when the shutter is open), and
when TTL metering is occurring and the exposure value is being adjusted in real time.
Pre-flash TTL Auto Exposure Adjustment is when the camera's internal strobe fires a flash before
the shutter opens, and this light reflecting from the subject is metered TTL, and the data resulting
from this is used set the main strobe's actual flash amount, so when the shutter opens and the
strobe flashes, the flash output is of a predetermined amount.
Reference No. 3
Camera's internal strobe fires one or more small flashes before the main flash. Reflected light
from the pre-flash(s) is measured by the camera and used to calculate the main flash duration, for
correct exposure.
INON D-180 Manual
Version 1.
October 4, 2003
Copyright 2002, 2003 by INON America, Inc. All rights reserved.
"TTL" – What is it?
"Pre-Flash" – What is it?
R-TTL
R-S
P-TTL
P-S
P-M
R-M
15
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