Kenneth Sloan wrote:
> OK - since I started this particular thread, and since I'm still
> confused, let me see if I have this straight. You are saying that the
> output of the F280 in Super FP mode is IDENTICAL on each and every
> exposure, completely INDEPENDENT of any camera setting and any available
> light? In other words...it's a heap of flash powder - best used for
> shots of tourists wearing floppy hats posing in front of the Grand
> Canyon?
William Sommerwerck wrote:
>
> "The OM-4Ti is probably better capable of Super FP flash because it can
> measure
> the influence of both the flash and available light during exposure."
>
> This is not correct. It is a major point of confusion. It's been discussed
> before, but maybe it needs to be rehashed.
>
> Super FP is a _manual_ mode of flash operation.
This is so far true as there is probably no change in the intensivity of
the flash output (there might be an change [optimatision] in the length
and
strength of the ilumination depending on the shutterspeed, but this
might
happend only under certain conditions).
> Instead of firing one big burst
> of light, the flash puts out several hundred smaller bursts over a period
> slightly longer than 1/60 of a second. Other than changing your distance from
> the subject or sticking a handkerchief over the flash tube, neither you nor
> the
> camera have any control over the flash's output.
The effective (on the film) flash output is limited by the aperture und
the shutter.
> Super FP is strictly for fill-in.
When your object is close, you better stop down the aperture to avoid
overexposure.
> The camera's normal controls (aperture and
> shutter) set the base exposure, with the flash providing fill-in at
> "reasonable"
> subject distances.
The flash output is not independent from shutter speed and aperture, it
will be calculated together with the natural light.
> In order for Super FP to be fully automatic, it would have to know the
> distance
> to the subject, the f/stop selected and the scene brightness, _before_ the
> exposure. The OM cameras do not supply the first two pieces of information, so
> Super FP cannot provide _automatic_ fill-in flash.
Even the camera did not know both values, it is still posible for the
camera to calculate an proper exposure.
My theory how automatic Super FP flash photography works as follows:
The flash starts to emit light in the same moment when the camera starts
to
meter the exposure in ADM mode (after fliping up the mirror and closing
the aperture). So natural light and flash light mix together on the
printed shutter curtain from which the camera meter reads the available
light and determines the exposure (shutter speed).
That´s another brilliant aplication of the ADM system.
Of course like every other flash there are minimum and maximum distances
for the proper use of the flash. By exeeding the maximum distance not
much
is happend, only the natural available light will determine the
exposure,
exiding the minimum distance will result in an overexposure. With an
aperture
of 2-2.8 you better stay more than a meter away from your object, not an
purely
theoretic limit in portrait photography.
William Sommerwerck wrote on another occasion:
> Nope. Look at it this way. Super FP is used _only_ for fill-in. Under such
> conditions, the base exposure is controlled by the ambient light -- the flash
> is
> merely a weak fill. There isn't enough light from the flash to have much of an
> influence on shutter speed. (If there _were_, the light would be too bright to
> be a fill. Right?)
To give you an impression how strong the Super FP flash is:
The camera meter showed an estimated shutter speed of 1/30s with 100
ASA, the
object was a little bit more than 1m away, aperture was 2.0, effective
shutterspeed was 1/2000s.
The flash was so strong that it outpowered the natural available light
by
6 stops!
Of course, the ratio of fill in can only be altered by reducing the
flash output
(or raising the level of natural available light) or changing the object
distance.
To reduce the flash output you might use ND filter or an wide angle
diffuser in
front of the flash, an built in flash output compensation would have
been handy
(especialy battery economy wise).
I´m talking of an "full automatic mode" because I have altered the way
the camera
is comunicating with the flash. The automatic syncronisation to 1/60s
with
attached flash is usefull for normal OTF flash photography, avoids blur
due to
long opening times of the shutter and gives you confirmation about flash
ready
and over- underexposure.
But in Super FP syncronisation it has the unpleasant characteristic
notto sync
with times below 1/60s, regulary resulting in underexposures when the
available
light requires shutter times below 1/60s. To avoid this you have to
switch off the
flash first, to check always the estimated shutter speed which is
anoying.
To solve this problem I taped over the flash ready contact, as you can
see below:
http://www.stud.uni-hannover.de/user/73239/schuh.jpeg
As result the flash syncs with shutter speeds longer than 1/60s and I
have
permanent automatic fillin flash without any problem.
Drawbacks are no flash ready and over- underexposure confirmation, but
the normal overexposure warning will still work if you use the memo
function to
check the effective shutter time (one nice thing with tapeing over the
contact is,
that the memo function now works together with the flash, but don´t
forget to
flush the memory before you take another shoot or you risk wrong
exposures).
With "Normal OTF" the camera behavior is similar to an OM-2 (without N),
resulting in an longer sync time of aprox 1/45s.
The limited way Super FP works with the OM3Ti is only due to the lack of
ADM metering with this camera (only flash OTF photography), which is no
design fault, but an limitation inherent with mechanical cameras.
Other manufactors which licened the Super FP flash use it also
strictly in manual mode (N*k*n N/F 90), obviously due to the lack of
ADM.
An shorter sync time of 1/250-300s would improve the range of the flash,
which is already strong enough (sometimes to strong) for fill in flash.
Somebody should not forget, that one reasons for Super FP flash is the
use with wide open apertures.
Regards
Richard
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