A technique John Lind once mentioned on this list using the OM-4t is to
adjust the aperture so the speed is around 1/60 - 1/15 with the flash in
OTF TTL. The camera will shoot at 1/60, giving a balance of ambient to
flash. This is one -OM-4T limited- approach to ambient/flash balance.
See John's appended emails below for more detail.
At 08:36 PM 8/17/2001 +0200, hnz wrote:
: There is no TTL/OTF flash control when in camera manual mode even
: with OM 4Ti???
> Unfortunately, no. This feature is only available in the OM-3Ti,
> where you can balance the available light / flash ratio by using the
> exposure compensation dial to change flash output and the shutter
> speed (in the range 1 ~ 1/60 sec) to change the influence of
> available light. If only Oly would be willing to upgrade the OM-4Ti
> to incorporate this feature...
...
> hnz
So, upgrading huh, here's a challenge: I've been toying with the idea
of replacing the controller in an OM-4t with one of the new 16 bit
micro-controllers from TI, that only takes 1uA of standby current. We
could retro-fit it into the existing low-light electronics of the 4t
and add the features we want. Here are some dream notes I made to a
fellow list member once on the subject of upgrading our OM's with the
new TI processor:
"Of course it would be limited by the existing mechanical hardware, but
adding rear curtain sync, or better flash control (such as allowing
shutter speeds less than 1/60 for fill flash), 1 second
mirror/diaphragm prefire, shutter speed and approximate aperture data
recording for later output through a serial interface to a pc {aperture
is known because the internal A/D measure the "relative" aperture ring
variable resistor, it may have to be user preset by selecting the lens
base aperture, I think. although maybe that is known also. Does the
aperture tab start in the same spot on all lenses or does it vary from
lens to lens?}. Once the new controller is integrated into the OM,
flash memory programming can be used to modify camera functioning, so
features may be tried out without having to even open the camera
(serial interface through the bottom plate contacts or maybe the flash
contacts). The display could be modified so that a moving dash could
indicate shutter speeds below 1 second (versus only the changing line
for >1sec). not only all that, but at a current drain lower than the
4t. the hilight and shadow buttons could be used for pre-setting
features, like the current frame count for data recording, setting
attached lens aperture or selecting custom options. If olympus is going
to drop the ball, somebody has to pick it up and carry the OM into the
21st century. .... ok back to work...."
Problem is, I don't know how to remove the existing controller on the
flex board without damaging the board. Any takers for such a project?
=========================================================================
Date: Fri, 09 Apr 1999 23:30:32 +0000
From: "John A. Lind" <...>
Subject: Re: [OM] T-32 Fill Flash Outdoors
At 23:18 4/9/99, Chip banged away continuously on his keyboard until he hit
the send button with his mouse:
>Does anyone have some tips on using T-20/T-32 for fill flash outdoors? I
>have an OM-4 ; no OM-4T. Thanks,
Here is how I do it with the same combo of OM-4 and T-20, T-32 *and* F-280
using TTL OTF mode:
1. Make sure the camera is in Auto mode with the ASA set for the film
speed you are using, and the compensation ring on the ASA dial is set to ZERO.
2. Mount the flash to the camera but leave it *OFF*.
3. Aim at your subject, focus, and with the flash unit *OFF*, adjust the
aperture ring until you get a 1/60th shutter speed.
Note: This is the sync speed for the flash unit and you will also be
properly exposed without any flash for the scene's ambient lighting.
4. Turn the flash ON.
Note: This "locks" the camera at 1/60th so the shutter speed cannot change
and the overall scene will stay properly exposed for ambient lighting.
5. Turn the compensation dial (without lifting it) counter-clockwise from
+2/3 to +2 compensation depending on how much fill you want.
Note: The dial moves in 1/3 stop increments. If you are compensating for
mottled shadowing caused by small tree branches over an otherwise sunlit
subject, you probably want more fill (+2/3 to +1). If you want only to
make eyes sparkle and enhance contrast slightly on a deep overcast day, you
probably want less fill (+1-1/3 to +2). Experience in doing this will
develop a sense of how much fill *you* want. Everyone's preferences are
different. This "fools" the TTL OTF metering into thinking the film needs
less light from the flash.
6. Shoot the number of frames you wish of the subject. Repeat steps 3 - 5
if ambient lighting changes.
7. Remember to turn the flash OFF and reset the compensation dial to ZERO
when you are done with fill flash.
To reiterate what you have done. You are using the aperture ring to find a
proper non-flash exposure at 1/60th second for the overall scene. You are
then fooling the flash unit and TTL metering combination into thinking you
need less light. However, the camera will remain locked at 1/60th shutter
speed as soon as the flash has charged.
I recommend you try this with a victim, er subject , on some non-critical
photographs and experiment with different fill levels (compensation dial
settings) both in mottled shade with bright sunlight and under deep
overcast. Keep records of what you did for each frame and then look at the
results. You can then choose what settings please you most for your own
fill-flash work.
Fortunately the OM-2[n, sp] and OM-4[t] use the TTL mode on the T-20, T-32
and T-45. This method should also work if you are using an F-280. There
is a different way to do this with a T-20 or T-32 in Auto (using the sensor
on the front of the flash unit) but it is more complicated and more
difficult to control how much fill you get.
Hope this helps you out some,
-- John
=======================================================================
Date: Sat, 10 Apr 1999 07:49:56 +0000
From: "John A. Lind" <...>
Subject: Re: [OM] T-32 Fill Flash Outdoors
Chip's question brought to mind another effect you can achieve with
dedicated flash and TTL OTF metering outdoors. It takes slightly more
work and unlike "fill" flash this would be better classified as
"overfill" flash as it seeks the opposite ratio of ambient to flash
than fill flash would.
Given a frontlit subject significantly closer than an equally lit
distant background you can highlight the subject and reduce the
background brightness with flash. This can be used to reduce the
distraction of the background in the photograph or achieve a darker
background if one is desired, but the subject cannot be positioned in
front of one.
1. Set the camera for *twice* to *four times* the ASA rating of the film
and Auto mode.
2. Bolt the flash unit on to the camera and leave it OFF.
3. Aim at the subject, focus, and with the flash *off* set the aperture
ring until you get a shutter speed of 1/60th.
4. Turn on the flash unit on (in TTL auto mode).
5. Turn the compensation ring in the *minus* direction until you have
compensated for the "push" you set the camera to in #1. (for twice the
ASA, use -1; for four times the ASA, use -2; etc.)
6. Shoot the photograph(s) and repeat 3 - 5 if lighting changes.
7. Remember to reset the compensation ring and ASA dial when you're finished!
This does the *opposite* of a fill ratio by setting up for more of the
light coming from the flash and less from ambient sources. What you
have done is set the exposure for ambient lighting one to two stops
underexposed at 1/60th second. Since the flash locks the shutter speed
to 1/60th the background, especially if it is significantly farther
away, will remain underexposed (darker). Recorrecting using the
compensation ring allows the TTL metering to provide correct flash
exposure for the closer subject.
This is a bit trickier than using the flash for fill and may require
more experimentation with a victim, uhhhh subject, to get a feel for
what the results will be and/or some "bracketing" with several
exposures when wanting to achieve this effect with a real subject. It
also may be *very* difficult (impossible?) if you use faster films as
you can easily run out of stops when closing down the aperture to get a
1/60 shutter speed. [Oh goody, this is the excuse I've been needing to
justify buying those ND filters!] It also requires the subject to be
significantly closer than the background or you will end up with
everything more or less equally exposed.
-- John
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