With the original OM-2, TTL flash exposure would stay open if the flash reached
full output without quenching the SBCs. After enough ambient light was
collected, the shutter would finally close. This allowed for good ttl flash if
you're in range, and interesting effects if out of range.
The small circuit in the bottom of the 2N (ZC1792) forces a 1/60th shutter speed
in ttl flash mode no matter what the flash puts out. So at (ie) 100' with a
T32, lens at f11, the flash will go full dump, the shutter will be open for 1/60
and you'll have underexposure, whereas the OM-2 shutter would stay open and give
you experimental results.
John
Camtech
Frank van Lindert wrote:
> Private communication with Wim made clear what the precise purpose of
> taping the flash contact is. It does NOT shorten the minimum sync time
> in any way - that always remains a (poor) 1/60th.
> But it does bring back the possibility of the old OM-2 to allow for
> exposure times LONGER than 1/60th, measuring the ambient and flash
> light together when in auto-mode.
>
> According to Wim, the old OM-2 didn't take the flashlight into account
> well enough. The OM-4(T) might overdo a bit on this point, emphasizing
> the flash light a little too much in its calculations of the total
> light needed.
>
> Frank.
>
> On Tue, 20 Jan 1998 14:21:10 GMT, Frank van Lindert <lindertv@xxxxxxx>
> wrote:
>
> >By mere coincidence I saw this hint from a fellow countryman in
> >rec.photo.equipment.35mm today.
> >
> >It concerns enhancing the flash capabilities of the T-20 (and probably
> >equal for the T-32) flashgun with OM-4 or 4T(i)
> >
> >Anybody comments on this one? I have asked Wim in a private email
> >message about his experience with sync times.
> >
> >Frank van Lindert
> >Utrecht - NL
> >
> >Quote:
> >
> >>On Tue, 20 Jan 1998 07:41:38 GMT, wiskerke@xxxxxxxxx (Wim Wiskerke) wrote:
> >>
> >>If you put the T20 on an OM4 or an OM4ti in auto mode, the
> >>shutterspeed will automatically change to a 1/60.
> >>Some people hate the Om4 for it.
> >>If you put a small piece of tape over the contact on the right (front)
> >>contact of the hotshoe, you sacrifice the flash ready signal, but you
> >>have *fill-in flash* or *open flash* capability in auto mode.
> >>
> >>Hotshoe layout on an OM4ti (the OM4 only has the upper three contacts)
> >>
> >> Lens side
> >> _________
> >>/ \
> >> o o ------------------- tape over this contact
> >> O
> >> o o
> >>____________
> >>
> >> Back
> >>
> >>I have taped over my 4's and 4ti's for about 8 years now. (It took me
> >>two years to come up with this. Once you know it it's simple.) And
> >>everything still works fine. I don't know if Olympus will approve
> >>though.
> >>
> >>good shooting, Wim
>
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