I have both the Minox B and Minox IIIS owners manuals in front of
of me right now.

1956 Minox IIIS:
[flash synch was new with this model so some preamble about flash
utilization, in the absence of an actual Minox flash unit to refer
to, is the first two paragraphs in the manual]
"... The shutter has built in synchronization of the X-type. ...
Flash Source
Electronic Flash Units ..... 1/2 second to 1/500 second
Flash Bulbs: SM, SF ..... 1/2 second to 1/100 second
M-2, 5, 8, 25.. 1/2 second to 1/20 second

A flash unit made by MINOX is expected to become available
soon, very complete flash instructions will be issued at the
same time."

1966 Minox B:
"...
For electronic flash, set the exposure dial to 1/200 sec. or slower,
attach the flash cable to the flash post of your Minox.
For flash bulbs, set the exposure dial to 1/20 sec. or slower. ..."

>The Minox shutter does not have variable size traveling
>slit. Instead, during shutter opening, the whole film plane
>is exposed , the duration is governed by the shutter speed.

I'm not certain but I don't believe this is true. It was true
of the single bladed Riga shutter, but the post-war Minox
shutters in A/B/BL/C/LX models (don't know about the EC) are
a two blade design with a traveling slit. From the above sync
specs, the slit would seem to be narrower than the full film
gate at 1/200 or above on the B, 1/500 on the IIIS (although
I suspect that that latter figure is incorrect).

>If instead the Minox shutter at high speed only exposed
>film plane partially, acting as if a slit, then we have
>serious problem--- it means that the effective aperture
>at high speed will not be a constant F3.5, and would be
>the smaller the higher speed.

Why so? This is exactly how all the focal plane shutters
in the world work, from Leica to Speed Graphic. The lens
opening is independent of the slit width. Minox simply
puts the shutter in front of the lens rather than behind.
They can get such a high synch speed even with the relatively
slow shutter blade travel speed because the lens is so tiny
and they don't need to travel the full width of the focal
plane either.

I have an old Honeywell Auto-Strobonar 110A which I bought at
a flea market for $2. It has only one automatic setting which
should nominally have me set f/5.6 for 100 speed film, but
when I measure it with my flash meter it produces a perfect
f/4.0 reading. I haven't used it yet, but I suspect this
will be perfect for use with the Minox, although it is
bulkier than the Minox electronic flash that came
with the EC. I don't use flash much anyway ... I find I can
hand hold reasonably steadily down to 1/20 second so 100
speed film for general purpose use or 25 speed for outdoors
works just fine.

Godfrey

=========================================================================
Date: Fri, 6 Dec 1996 10:53:00 EST
Reply-To: The Subminiature Photography Mailing List
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Sender: The Subminiature Photography Mailing List
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From: Michael Goldfarb <MGOLDFAR@MAIL.MOBIUS-INC.COM>
Subject: More thoughts on Minox flash sync

I wrote:
-> The Minox III-s (okay, Martin: A) and B sync at 1/20 for flashbulbs
-> and 1/100 for electronic flash.
->
-> The Minox BL [and C - I was wrong before] syncs at 1/30 and 1/125,
reflecting its different
-> speeds.

Martin wrote:
I believe the Minox A/B flash sync at all speeds, from
1/2 up to 1000, ala leave shutter.
Focal plane shutter cannot sync at higher speed due to its
travelling slit principle--- only a slit on the film plane
is exposed.
The Minox shutter does not have variable size traveling
slit. Instead, during shutter opening, the whole film plane
is exposed , the duration is governed by the shutter speed.
If instead the Minox shutter at high speed only exposed
film plane partially, acting as if a slit, then we have
serious problem--- it means that the effective aperture
at high speed will not be a constant F3.5, and would be
the smaller the higher speed.
I don't think it is the case.
=========================
Interesting - maybe the folks at MPL suggested 1/100 for electronic flash as
sort of a nominal speed when I asked them. The test shots I did at 1/50 and
1/200 were definitely OKAY, but I THOUGHT I saw falloff on the edges.
Perhaps I only FELT that I saw the falloff because I expected it a la a
focal plane shutter. I should look carefully at them again...

If it's true that X-sync works at a wider range of speeds, this is a useful
piece of info, since you can't vary the aperture on a Minox as you would to
get proper exposure when using a manual flash on most other cameras.
Somebody who's pushing more film through than I am - I'm only doing a roll
every month or two - should try syncing at higher speeds. If a Minox can
really sync at 1/1000 (or 1/2000 on a LX), it means you could freeze even
really fast action.

And, at the other end of the scale, if you can really sync a Minox at, say,
1/20, this might mean that the little Minox EC flash could be very useful
despite its low power...

Wait a minute. The duration of electronic flash is really short (on the
order of 1/10000, or even shorter, right?) - changing the shutter speed
shouldn't affect exposure in the same way as aperture would, because the
flash illumination is constant. (It might affect it in that more ambient
light and reflected light could be recorded, though.) Shooting at different
speeds might be useful for freezing/blurring the action, but not for
changing the exposure - not very much anyway.

Okay, forget about changing the speed for significant exposure differences.
But knowing that, for example, you could shoot with flash at 1/500 when
taking shots of people dancing or horses jumping would come in handy. Also
for shooting at 1/10 - assuming you can hold at 1/10! - to get a blurred
version of the same subjects, but with a brighter frozen portion of the
motion corresponding to the flash fire...

Very interesting... too bad using flash with a Minox just isn't that
practical!

MSG
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