but the TTL flash will be influenced by the background, no? if one wants
the BG -1 stop, then the flash will try to compensate and will overexpose
the subject. it seems that if you meter the background, then spin the
compensation dial to adjust for the over-exposure, then you havn't really
made your life easier (or more accurate) than manual GN.
also, i don't think i understand your test. why did you use the memo
function? this essentially puts the camera in manual mode instead of
letting the TTL read the light. with the -4 and taped contact, one does
indeed get SS lower than 1/60. i think in your instance, the camera shut
down at 1/60 as the flash put out enough light to fill the exposure. i am
also sure that the flash will be controlled by the TTL as it has variable
recycling times and not the long one as if it had just done a full dump.
the beauty of having the AUTO is that it will read both the ambient and
flash light to fill the exposure needs.
i didn't think about using the flash on AUTO with the camera on manual. it
seems like it should work just as well, but only if the flash is mounted on
top of the camera.
i'm not trying to knock the -3Ti, just trying to understand it! ;) also,
sorry for my butchering of the language - i'm much more of a numbers guy. ;)
Bob
<snip>
The magic with flash on the OM-3t is being able use TTL flash while
also using slow shutter speeds to fill in the background. You can
compensate the amount of (fill) flash light with the exposure
compensation dial. As you note, taping over the contact on the OM-4t
allows the 4t to do flash auto exposure at lower shutter speeds, but
the auto exposure mode will adjust both the speed and the flash, while
in manual mode with the 4t (and contact taped over) you will have to
use guide numbers or use the flash's internal auto exposure control.
The 3t is manual speed even with TTL auto flash exposure, so you can
use the flash with OTF exposure while controlling the amount with the
compensation dial.
I just did an experiment with the OM-4t and contact taped over. I used
a flash meter to check the result. With the contact taped over, camera
in auto, and memo activated to record the actual shutter speed. The
meter said normal exposure should be 1/4 second. With the flash firing,
the actually speed was almost 1/60th. This makes sense, the flash fires
when the shutter is fully open, gets enough light and closes, result:
the shutter sync speed. (note you need a piece of film in the camera.)
So you can't quite do what the OM-3t does - TTL flash control with
manual speed. With the 4t, you have to use the flash's auto exposure
with camera in manual mode to do the same, not TTL OTF flash.
Wayne
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