Subject says it all - an old stager is still around, albeit quiet for so
long.
Good to see you again, John.
Piers
-----Original Message-----
From: John Lind [mailto:j-a-lind@xxxxxxxxxxx]
Sent: 19 May 2011 18:41
To: Olympus Camera Discussion
Subject: Re: [OM] OM TTL flash behaviour
The amount of light admitted to the film plane in TTL is ambient @ selected
f-stop & 1/60th plus the necessary duration of flash to satisfy the TTL
metering.
There are some occasions for desiring to increase ambient by using 1/30th
(versus opening aperture by a stop) and you cannot do this in TTL, only in
"Auto" or "Manual" modes. TTL always sets shutter speed to 1/60th *if* it
needs to fire the flash to get enough light. If ambient is sufficient TTL
will use shutter speed 1/60 or faster based on selected aperture; flash can
be forced by stopping down if possible, the increased DoF is acceptable, and
flash is desired. I've done the latter to force fill by stopping down just
barely enough to activate the flash.
-- John
Sent from my iPhone
On May 19, 2011, at 10:42 AM, "Walters, Martin"
<Martin.Walters@xxxxxxxxxxxxxxxxx> wrote:
> In spite of the eloquence and expertise of Dr Flash and others on the
> list, flash remains something of a "black art" for me. As I rarely use
> flash, my usual approach is to simply put my non-Oly dedicated flash
> on TTL and fire away. For info, the flash is a Braun 340 SCA (full
> TTL with the correct adapter shoe), in auto it has two selectable F
> stops (F4, F8), a swivel/bounce head with zoom (28-50-100). The filter
> set includes a diffuser (coverage for 21mm), ND4, and coloured filters.
>
> So, I'm taking a flash 101 course, which looks to cover pretty much
> all the topics. I'm in an interesting position as the only film
> shooter in the group (we're 8-10). Some of the CanNikon gang appear to
> have serious gear, and some of those camera/flash combinations are
> probably more intelligent than I am.
>
> After a couple of courses it's obvious that I'll have some challenges
> and some of the concepts will be theoretical rather than practical
> (e.g,, flash compensation, though the instructor lent me an EOS to
> work with; varying sync speed). My dedicated flash has some
> significant limitations, especially no or only very basic power
> control (filters on the flash). That being said, the instructor was
> quite intrigued that I had full TTL capability both on and off camera.
>
> One of the things we've looked at is compensation (both exposure and
> flash). So, this weekend I'm planning to spend some time test shooting
> to see what happens with various setups under TTL. In the meantime,
> I'd be grateful for some info on how exposure compensation on an OM2N
> affects TTL flash. I assume that it will affect both metering and
> flash, which is controlled by the meter (I believe modern N*kon
> bodies, for example, treat the two independently). Is this correct?
> However, that brings up another question: if exposure compensation is
> active, how does the OM actually compensate, when it automatically
> fires as 1/60 with a dedicated flash?
>
> As a third question, AG and Dr Flash have talked about underexposing
> the background by 1 or 2 stops. One method mentioned was to set the
> aperture for 1/30 exposure, and letting the OM fire at 1/60. I
> understand the concept - and here my ignorance is showing - but does
> this work in straight auto or in TTL as well?
>
> In anticipation of suggestions to get a different flash.... Yes, I've
> thought about a T32, though it appears only slightly more flexible
> than the Braun, and a Vivitar 285, which doesn't do TTL but allows
> control of flash intensity. However, the lazy side of me doesn't want
> to throw away TTL.
>
> As far as sync speed is concerned, I could always get out my Pen F,
> which syncs at all speeds. Of course, no TTL, and life is probably too
> short to deal with other challenges!
>
> Martin
>
>
> --
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