Maat asked:
>>>A question though, when it senses a TTL flash in auto mode, does it
automatically set the shutter speed to 1/60 (or slower??)?
Thanks again
>>>
Great question Maat. According to a book called "How To Select & Use
OLYMPUS SLR CAMERAS", the answer is "NO". I don't know if your flash will
work just like the Olympus ones do but the following is for the Oly TTL
family:
================
"TTL Auto Operation - Set the camera to AUTOMATIC. Install the flash contol
panel with the blank side out. (On mine it says "full-automatic control by
OM-2".) Turn on the flash. Select any aperture on the lens that produces a
shutter speed of 1/60 or slower with the ambient light. If the camera is on
programmed auto, the camera sets both shutter speed and aperture. (Didn't
he just tell us to set it to "AUTO", not "PROGRAM"?) Wait for the
flash-charge indication. Press the shutter button.
Check the exposure indicator. Shoot again or turn off the flash."
================
You can use TTL flashes (T-20, T-32, T-45) with the camera in either the
AUTO or PROGRAM mode. (Note that the OM-1 and OM-3, being manual exposure
cameras, do not allow you to do TTL flash since TTL is an auto capability.
Duh.)
What he's saying is, if you're loaded with an ASA 100 film and you're in
daylight, in AUTO mode, you won't get the flash even if you're set at f16,
since f16 @ 1/125 is correct exposure and it's too fast to flash sync on the
OM-2, and OM-PC.
But if you put in Kodachrome 64 and use a polarizer, and you're still at f
16, in full daylight, pointed at an average scene, suddenly the "correct"
exposure without flash is around 1/15. This is where it gets interesting.
If your flash is in a TTL shoe but it's switched OFF, you get 1/15 at f16
without flash. But if the flash is ON (and set with the TTL panel facing
correctly, duh) the camera will open the first curtian, ask for the flash,
sense that it has correct exposure (mostly from the flash exposure) and
close the second curtian. Total shutter duration: Sync speed, 1/60th.
Although the viewfinder was telling you the shutter speed _predicted_ was
1/15th, the flash shut the curtian at the sync speed of 1/60. This is
correct operation.
What scares me though, is if you take the polarizer off, and shoot K64 at
the beach, you might get this: Point the camera at the dark grey concession
stand, get 1/50 @ f16 with a minimal flash exposure that quenches
immediately. Point the camera at a white pail in the white sand, get 1/80th
at f16 and no flash. This is why the manuals tell you to try to chose an
aperture that forces a shutter prediction of 1/30. Don't try to sit on the
very edge of 1/60th.
Originally I thought that daylight fill was the whole reason to have TTL.
The same book discusses fill-flash using *manual* flash calculations, at
fixed (read: short!) distances. He doesn't even mention using TTL to do
fill-flash. Instead he simply says TTL is great for "close-up and macro
photography".)
Jim
PS- The N*kon N80 does fill flash. Want the flash to be -1/2 stop, relative
to the main exposure? Just dial it in. Want -1 and 1/2 stops? Dial it in.
You can't do -2/3 stop though. Too bad for slide users.
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