Paul Waserbrot axes:
...what's needed to do to make the camera aware of the flash.<
Camera OM-1 w 50mm 1:1.4 lens<
Flash Popular SC-7<
The short course is:
1. Turn that puppy on
2. Fire away
Okay, it's a bit more involved than that. First you gotta set the camera's
shutter speed to 1/60 or less ... longer ... slower ... uhh ... somewhere
between 1/60 and 1 second. This is getting more complicated than I thought
... okay, don't set the shutter speed anywhere between 1/125 and 1/1000 when
using flash.
Synchronization speed is what I'm fumbling for here. The shutter's gotta be
fully opened when the flash pops. Otherwise you'll have a dark line where
the shutter curtain blocks part of the film. That starts happening at 1/125
and gets worse on up with faster shutter speeds.
Also, make sure the little doodad on the left side of the lens mount area -
marked "FP" and "X" - is set to "X". That's for electronic flash. FP is
for a type of flashbulb that's uncommon to the point of being on the
endangered species list now. Flashbulbs had a longer ignition time and
relatively slower peak brightness duration, so a different type of
synchronization was needed when those bulbs were still commonly used.
Here's the hard part.
Is your flash fully manual or does it have some auto features? If it has a
little electric eye or sensor on the front, it's got at least some auto
features. But those sensors can be difficult to spot on some flash units
(e.g., darn near IMPOSSIBLE to find on the Olympus T20 flash). So check the
scale or dial on the rear or side. If it's got any auto features at all
it'll either say "Auto/Manual" somewhere; or there may be a scale marked in
black and red, or black, red and green; or there may be arrows pointing to
different f/stops. If you see any of these, it's probably an auto flash.
If you don't, it's probably a manual-only flash.
The simplest way to get acquainted with a flash is to practice as though
you're using ASA 100 film. Line up the ASA indicator on the flash to 100
(or 21 DIN if it's an old unit). Then find the indicator for 10 feet. Then
find the f/stop that most closely corresponds with the 10-foot indicator.
Multiply the f/stop by 10 and you have the approximate guide number for that
flash unit. The guide number is an indicator of the maximum output the
flash is capable of.
I'm looking at two flash units now. One is a fairly powerful Canon unit
with a guide number of around 95 - I estimated that because the 10-foot mark
lies between f/8 and f/11. The other is an Olympus PS200 flash - its guide
number is 45. How do I know this? Because PS200 stands for "PipSqueak
200". And anyway, it's marked on the flash.
The PipSqueak is an all-manual unit. When I was younger and might have been
able to read the ridiculously tiny scale without a magnifying glass, it
would have told me that at 10 feet I should set the f/stop on the lens to
4.5; at 4 feet I'd set my f/stop to 11; at 33 feet, to f/1.4. Much beyond
in either direction is anyone's guess.
Like any good auto flash my Canon AB46, Olympus T20 and many others save me
from this horrible agony. With the Canon unit I set my aperture to f/5.6
and at any reasonable distance - roughly 1.5 to 15 feet - I can fire away
without worry because the sensor will tell the flash to shut up when it's
had enough light.
And 750f the time the auto flash setting will work. It will reliably
expose white kittens against a white wall, black kittens hiding inside black
shoes, and grandchildren hiding behind rocking chairs.
But the other 250f the time, when your butt is on the line and you have
one chance to get that shot of the councilman who's just been indicted or
you'll lose your job ... you guessed it, the auto flash will be in the john
taking a leak.
Here's the problem. The sensors are placed right where your hand can block
them if your not careful. So the reflected light off your hand tells the
flash to shut down prematurely. And try as you might to remember this,
hands will do what hands will do.
Here's the other problem. Auto flash only works reliably in moderate light
- hazy days, open shade, well lighted indoor areas like classrooms,
conference rooms, etc. At night, in dim hallways or motel rooms (do we
still take those kinds of photos?), once again, auto flash will be ...
smoking a cigarette or goofing off. It can't quite tell how much is enough.
So you gotta learn those guide numbers, like it or not, for the 250f the
shots. So get acquainted with the auto flash f/stops you can use for each
ASA speed film you use, and the guide numbers so you can make sense of them
reasonably quickly when your nephew decides it's cute to try to put an
entire kitten in his mouth.
Lex
(BTW, if none of this works, either you forgot to put batteries in the
flash, or it's broke.)
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