Matthew Granger wrote:
> When you say voltage is very important... is there any chance that
> international models would have any problems? So the T32 works in fully auto
> mode with E-series huh?He refers not to the voltage powering the flash, but
> the voltage on the pin that the camera uses to trigger the flash.
>
Back in the old days of electronic flash, thyristors didn't exist and
cameras had mechanical switches to set off the flash. So the whole
voltage of the flash capacitor was grounded through the flash tube by
the camera switch. So some old flashes have voltages like 300v. Newer
flashes, and I'm generally talking starting 20+ years ago, started to
use electronic switches, thyristors, to trigger the flash, and the
voltage the camera see went down to under 15v, often lower.
Then along came electronically operated cameras. And most of them
couldn't handle 100s of volts without damage. Then came the first
digital SLRs, adn one of the first important ones, the Canyon D30, was
speced at something like 6v max. That's changed, and contemporary ones
will handle much more voltage, check your owners manual for yours.
None of the Olympus T series flashes will be a problem. And they are
nice flashes. However, the sophisticated TTL auto circuitry you are
paying for will go to waste on an E-thingie. It's easy to find a
perfectly good used flash from a maker like Sun, Vivitar, etc. for
$15-20 that will work just as well for an E-thingie. I've not looked at
new prices, but you certainly chould be able to get a very nice one new
for well under $100.
The one design weakness of note with the T32, and especially with the
smaller T20, is that the flash tube is close to the lens. so they cuffer
from red-eye more than the generic flashes the stick up in an inverted
'L' shape.
To define terms that will otherwise cause confusion, flashes may have
three basic modes:
1. Manual. You set a fixed power level on the flash and aperture on the
camera based on the subject distance. This is the method Dr. Falsh
strongly recommends and uses in his portrait and event photography.
2. Auto. Here, you match a fixed aperture with one of possibly several
auto settings on the flash. A little photocell on the front of the flash
measures the light reflected from the subject and shuts off the flash
when it has provided enough light. The is the Auto mode to which Ali was
referring. This mode works with any camera, film or digital, as the
'smarts' are in the flash.
3. TTL Auto. Similar to Auto, except the light is measured after it goes
through the lens, so a fixed aperture isn't needed. This is the mode
used by most DSLRs, and each brand has proprietary systems, In fact, it
isn't uncommon for flash to camera compatibility to not be universal
even within brand and camera type. That's what those very expensive Oly
flashes for DSLRs that you mentioned are.
4. TTL-OTF. This system was developed by Minolta, but it was Oly,
starting with the OM-2 who really made it a winner. It's like TTL Auto,
except that it measures the light reflected off the film and a special
shutter curtain, so it can react to light changes during exposure.
That's what the T series flashes are. However, if you look closely at
the 'O' in the Olympus name on the front of the T20 and T32, you will
see a photocell hidden. They also work in regular Auto and manual modes.
Moose
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