2. When using FL-50 in Program mode, the camera just sticks to
widest aperture, and seems to turn off program shift. Not much of a
problem, sinse I use the camera mostly in Auto mode, but still
annoying.
There is an old dictum: "a good flash picture is one where you
can't tell that flash was used." One way of accomplishing this
goal is to balance the brightness of the flash as closely as
possible with the brightness of the available, ambient light within
the scene.
This seems to be one of the operating principles which guide the
E-1 when used in Program exposure mode with TTL. When shooting
indoors, the E-1's exposure Program first meters the available
light within the scene and selects a shutter speed and lens
aperture which will give the best possible exposure. The lens
aperture is opened up in steps as the shutter speed is slowed down
in steps - depending on how much brightness from available light is
illuminating the scene. Once the maximum aperture has been
reached, and the lighting grows progressively dimmer, the shutter
speed will keep going slower until correct exposure has been
achieved.
Now, if the E-1 is in Program exposure mode and the camera senses
the presense of a TTL capable flash unit - it will attempt to
balance the brightness of the flash as closely as possible with the
ambient light which is already present within the scene. In dim
lighting conditions, the lens aperture will open to the widest
f/stop available - in order to gain as much exposure as possible
from the available light. The brightness of the TTL flash will be
regulated so that it is no more bright than the wide-open lens
aperture requires.
Ambient light exposure is determined by the shutter speed, as well
as the lens aperture. If the camera does not detect the presense
of a switch-on flash unit, it assumes that a tripod will be used
and the shutter speed will be slowed down by the Program to
whatever speed is necessary to achieve correct exposure. If the
camera is hand-held at slow shutter speeds, and no flash is used,
camera shake will cause blurring of the image -and thus the need
for tripod mounting.
If the camera detects a switched-on flash unit, the Program assumes
the camera will be used hand-held. Consequently, the Program will
not slow down the shutter speed beyond the point where the camera
can be hand-held without blurring the image due to camera shake.
For example, if the foical length of a zoom lens is set to 14mm -
the shutter speed will not go below 1/30th sec. But if you zoom in
the lens to 54mm, the shutter speed will not fall below 1/100th
sec. The shutter speed selected by the program will always match
the slowest speed which can be safely hand-held for the focal
length of the lens.
This is really an excellent implementation of an "expert system."
That is to say, when the E-1 is in Program mode and senses a TTL
capable flash unit - it will set the the lens aperture, shutter
speed and brightness of the flash in exactly the same way, and for
the same reasons, that an "expert" photographer would set all of
these parameters manually.
Of course, using the Program mode with TTL flash forces the
photographer to completely surrender control over both lens
aperture and shutter. If for example the scene requires more
depth-of-field than the wide-open aperture which Program mode will
often provide - it would be better to shift from Program to
Aperture Priority exposure mode, and select whatever f/stop you
feel is appropriate. Or, if there is subject motion which needs to
be frozen, requiring a faster shutter speed than Program mode has
chosen - then shifting from Program to Shutter speed Priority
exposure mode will enable setting the shutter speed you feel is
necessary. And of course, choosing Manual exposure mode will
enable the photographer to set both lens aperture and shutter speed
manually. The great thing about TTL flash is that the brightness
of the flash will always match the lens aperture, whether that
aperture was chosen manually by the photographer or automatically
by the camera.
The Program mode of the E-1 is very, very smart when it comes to
using TTL flash - smarter than many other competing cameras. It
adjusts the shuttter speed to match the focal length of the lens in
a way which allows maximum available light exposure while
minimizing the blurring effects of camera shake. And it also
adjusts the zooming reflector of the flash so its coverage matches
the angle of view of the lens. This system is way more
sophisticated and effective than the E-TTL system on the Canon 10D,
for example. So if one is annoyed by the way Program flash works
on the E-1, all you need to do to feel better is try out about any
other dSLR.
Gene Windell
