ALI wrote:
> Yep the TTL cord pins are in the same position as the T-32. I fired up
> a couple of test shots and it works well. The lighting seems right on!
They have to be in the same position on the cord or the T-32 wouldn't work.
>
> My question in reference to someone else's post about setting the flash
> to AUTO and the camera manual. I found that setting the flash to auto doesnt
> work all
> that well....in fact setting the flash to manual and using the appropriate
> aperture setting works much better. Is there an advantage to going with auto
> rather than manual?
Whether the flash does well in auto mode depends on what the background
is. It can be easily fooled. What you need to do is take a test shot
and then apply "flash exposure compensation" by tweaking the aperture.
Auto mode and tweaking may be the best bet for bounce flash since guide
number calculations are useless. However, manual mode and tweaking also
works for bounce mode. It's just harder to guess the starting point.
If you're using direct flash it will always be more accurate to use the
guide number and a manual calculation based on distance to the subject.
Be aware, however, that most flashes (T-32's included) are a little
(maybe even a lot) optimistic about their guide numbers. Another point
of sometimes very significant error is the recycle time and battery
voltage. To get to 100% full power T-32's (and others as well) require
a lot longer than the spec says. If you're using NiMH or NiCad
batteries you'll also never reach the full guide number because:
1) it's optimisitic to begin with and
2) getting to 100% is critically dependent on full AA alkaline battery
voltage. The alkalines put out more flash power to begin with but
quickly drop by the wayside as their voltage drops off. On the other
hand, NiMH's put out fully 1/2 stop less power than fresh alkalines. If
you were buying modern Canon EX flash units you'd have to pay a couple
of hundred bucks to get that much power differential.
The following is data from a test of four T-32's I did a couple of years
ago. The first part shows readings of 1 up to 4 flashes ganged together
both at the center of the field and at the edge of the field with a 28mm
lens. Edge fall-off at 28mm is shown to be 1/2 stop or less.
Unfortunately, I didn't have my high voltage battery pack at the time I
did these tests and I don't know how much it might improve the power
output as I've never tested it like this. It knocks the recycle time
down to about 3 seconds though.
OK, here's the data. A note on aperture notation which is taken from my
Sekonic L-358 meter: f/ 8.0.2 means f/8.0 + 0.2 stops.
----------------------------------------------------
T-32 flash power and recharge test
@ 10 feet, ISO 100, no diffuser, max power
Center Edge of 28mm field of view
1 unit = f/ 8.0.2 f/ 5.6.8
2 units = f/11.0.1 f/ 8.0.6
4 units = f/16.0.1 f/11.0.7
@ 10 feet, ISO 100, small umbrella, max power
Center Edge
1 unit = f/ 4.0.0 f/ 2.8.6
2 units = f/ 4.0.9 f/ 4.0.5
4 units = f/ 8.0.1 f/ 5.6.7
@ 10 feet, ISO 100, no diffuser, at 1/4 power
Center Edge
4 units = f/ 4.0.2 f/ 2.8.7
Note: All 4 units test within 1/3 stop of each other. Output is very
sensitive to battery voltage. AA alkalines produce about 1/3 stop less
output after 20-30 flashes.
Output with alkaline AA’s at 1.54 volts = f/ 8.0.4, at 1.33 volts =
5.6.9. Actual measured guide number with fresh alkalines is only 84 vs.
spec of 104.
5.6.9 is the max observed power output using 1800mah NiMH batteries or
0.5 stops below max with alkaline.
A single T-32 is approx. 100 watt seconds compared to Lumedyne at 100 w/s
Recycle times with 1800mah NiMH batteries. Power measured at 10 ft.:
Time Power, f/stop
5 sec f/ 4.0.9
7.5 sec f/ 5.6.3
10 sec f/ 5.6.6
15 sec f/ 5.6.7
20 sec f/ 5.6.8
Note: Max of f/5.6.9 observed for NiMH batteries still not achieved in
20 seconds.
Chuck Norcutt
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