Shooting Mode Selector ®
The shooting mode selector 5 has five click-stop set- tings .The shooting modes that can be used with specific cameras are listed on page 28.
"TTL" position-TTL (through-the-lens) Automatic Flash Mode
This mode, which can be used only in conjunction with th e Nikonos -V camera, automatically controls the flash exposure Through-The-Lens(TTL). In this mode, the Nikonos -V's 8PD (silicon photodiode) reads the light passing through the lens and automatically signals the 88 -102 to turn itself off when the exposure is correct. Because the range of useable apertures is larger (trom f/2 .8 to f/22 when using ASAII SO 100 film) than with non-TTL flash, you can shoot at a variety of flash-to - subject distances. The farther the subject, the more light emitted by the flash unit; the closer the subject, the less light given off . In addition , the TTL mode makes daylight fill -in flash and close-up photography easier than ever.
-The useable film speed range for TTL operation is from ASA/ISO 25 to
400.For information about the apertures that can be used at va rious film speeds, see page 23.
-TTL operation is not possible with the Nikonos IV-Aor III or when the Nikonos -V's shutter speed/mode selector dial is set at M90 (lI90sec.J or B(Bulb).
-Even if the Nikonos-V's shutter speed/mode selector dial is set from 1/30 to 1/I000sec., TTL operation is not possible when : the sync cord is not securely connected, the ASA/ISO film speed is set beyond ASA/180 400, or the batteries are completely exhausted.
"AUTO" -Non-TTL Automatic Flash Mode
When the optional Sensor Unit SU-101 is used , this mode provides non-TTL automatic fl ash operation . In this mode, the sensor unit reads th e light reflected back from the subject while the speedlight is firing and tells the speedlight to turn itself off when the light output is sufficient for correct exposure. The selector dial on the back of the SU -101 allows one of two aperture settings to be selected according to the flash -to -subject distance and the shooting situation .
-In both the TTL and non-TTL automatic flash modes, the 8B-l02 emits amounts of light sufficient for subjects having average reflectivity. Therefore, correct exposure may not be obtainable if the subject's reflectivity is extremely low or high.
"MFULL", " M1/4" and " M1/16" -Manual Flash Modes
Manual control is very convenient when the correct exposure cannot be obtained through non-TTL auto - matic operation . The S8 -102 has three manual control modes for selection according to the flash-to -subject distance and the shooting situation . The guide numbers are GN 32 (16) at the " MFULL" position, GN 16 (8) at
"M1/4," and GN 8 (4) at " M1/16 " (when using ASA/ ISO 100 film . The guide numbers in parentheses are for underwater photography). To determine the correct aperture, use the exposure calculation dial or perform the calculations yourself (see pages 25 to 26).