Hello Don,
Thanks! Clarifies already a lot.
When in auto red mode and using ISO200 film, the flash says to use f/5.6
aperture. These settings, when using the flash in manual mode (=maximum
power?), would give a reach of 7m (24ft). That's not quite a lot,
considering all light-loss factors that you mention before, which
explains why I couldn't get proper exposure for bounce flash in auto
mode (even if it is not optimally "formed"---which I will certainly try
out).
Basically, the conclusion seems that the flash is (even theoretically)
not powerful enough for bounce flash in auto mode (at f/5.6,ISO200).
Using another film is no solution, as the flash compensates f-value for
ISO-value.
Something I could try is to switch to TTL-mode, so I can set the
aperture to whatever I want (f/2 e.g.) and use more sensitive film. This
will stretch my bouncing-range significantly, I'd imagine.
Does this reasoning sound sane?
Groeten,
Vic
Don Sanderson wrote:
Hi Vic,
There are a few things to remember when using bounce
flash:
1.) A ceiling, even a white one, diffuses and absorbs
a lot of light. Losing 1-3 stops of light isn't
uncommon.
2.) When bouncing, the distance from flash to subject
increases dramatically, it becomes the distance from
flash to ceiling plus from ceiling to subject. Since
light decreases in proportion to the _square_ of the
distance, doubling the distance decreases the light
to 1/4.
3.) When bouncing, the flash should be aimed about 1/2
way to the subject, aiming straight up puts most of
the light on you, not the subject. This is most
evident when the ceiling is low. Think of bouncing a
rubber ball off the ceiling and hitting the subject.
Also, if this is a flash that has not been used for
a while it has probably lost a good bit of its power.
This can be remedied by "forming" the capacitor in
the flash.
To do this let the flash charge up for several minutes
and then fire it in manual to get a full discharge.
Repeat this 10-20 times, this should bring the
capacitor back to near full efficiency.
The 280t is a very good flash, it is still a _current
model_, pretty impressive in this day and age!
HTH
Don
-----Original Message-----
From: Vic Mortelmans [mailto:[EMAIL PROTECTED]
Sent: Sunday, December 18, 2005 3:57 AM
To: pentax epostlijst
Subject: Bounce flash AF280T
Hello,
I recently bought a used Pentax AF280T, with auto and TTL features. This
flash should be capable for being used for bounce flash, isn't it?
When I use the 'test' button, I only get the green light when aiming the
flashlight directly to the subject. Even in a room with a low, white
ceiling, I couln't get the green light when aiming the flashlight to the
ceiling (completely vertical, or at an angle slightly towards the
subject). The flash was in auto-mode. I tried both green and red mode.
What does this mean? I had the impression that this flash is quite
powerful, even to today's standards? What's the use of combining
swiveling flashhead and auto/TTL measuring features if they won't work
together?
Not wanting to use direct flash, I ended up opening two stops above the
flash-indicated setting, hoping this will give me acceptable exposure...
(results to be expected still).
Slightly disappointed greetings, but with remaining hope that someone of
you will let mee see the light...
Groeten,
Vic
