Hi Fernando, Ken, Chuck and all,
> From: Ken Norton <ken@xxxxxxxxxxx>
> Yes, Carlos, you would need an electro-mechanical device to press and hold
> the plunger for the regular camera shutter release. You cannot do
> bulb-exposures with the winders as the triggering device.
>
Sure. The problem lies in the winder (or motor drive) itself. The mechanical
connection with the camera's shutter release is via a swinging pin. No
matter how long the "electronic" release is hold pressed, the pin will make
just a quick back-and-forth flick.
> One possibility that I'm thinking of is to use the Olympus IS-1, IS-2 or
> IS-3 cameras. In Bulb mode, they are press to start, press to stop and then
> it auto-advances the film.
It's called 'T' in classic cameras, but...
> As these are the bargains of the century
> (outstanding zoom lens,
Zoom lenses and astrophotography don't match very well :-( And much less
electronic shutters. The OM-2 (& 4) shutter operates mechanically at the B
setting, electronic otherwise.
> From: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxxxx>
> Carlos, If I understtod well enough, this would be the orthodox and
> expensive device you may be looking for.
> <
> http://olympus.dementia.org/eSIF/om-sif/motordrivegroup/remote_controller.htm
> >
>
That would be just the electronic part... but the electro-mechanical is
still missing. I can, however, reproduce a simplified version of that Oly
thing.
This would be good for winding the film _after_ the exposure, but wouldn't
keep B as desired.
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
> You need a Mynolta A1. (built-in intervalometer)
>
Same as with the IS series, plus...
> From: Ken Norton <ken@xxxxxxxxxxx>
> You missed the part about "astro-photography". The A1's sensor would be
> good for, oh, maybe 1/30 of a second.
>
Yeah, and the reliability of a digicam after a whole night, probably on a
very cold place...
> From: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxxxx>
http://www.flickr.com/photos/fernando_gonzalez_gentile/3708012765/sizes/o/
>
> What about this one? Ever seen one of this?
> Works flawlessly on the Winder2, both Auto and Manual (didn't try B, but
> it should).
> I'm sorry I cannot part with it. :-(
>
> Fires continuously for 10 seconds, at whatever speed, Auto or Manual
Except B :-( Basically, that's a simplified version of the Oly gadget.
> From: Ken Norton <ken@xxxxxxxxxxx>
> Well, there are three functions that need to happen.
> 1. The pressing of the shutter release and HOLDING it down. Bulb exposures
> do not work when pressing and holding the electronic release on thw winder
> or motordrives.
That is correct,
as already mentioned. That's the task for the electro-mechanical
device of my dreams...
> 2. The eventual release of the shutter release.
Again. Releasing the standard button with the winder _won't_ advance the
film, so we also need...
> 3. Film advance.
>
This is the easier part; just a pulse on the winder's remote connection
will do that -- but no exposure.
> From: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxxxx>
> Tried it on Bulb, Ken - a burst of shots during 10 sec.
> That is: no B.
We already knew that ;-)
> But on a dark night, iso 400 film, on Auto mode it will keep long
> exposures ... 2' is a rather long exposure, maybe enough maybe not.
Still too short, and do you think our priceless 357 batteries would last a
whole night of open shutter? (several rolls of 36x 2' exposures) Plus that
would make the OM-1 useless.
Meteor shower recording is probably the most frustrating task in
astrophotography... When
you are getting a picture of a nebula or something, no matter how faint or
small it could be, it won't move and if you have (or want) to use a slow
lens and/or film, you can make an exposure as long as needed to record it --
well, not exactly: you have to finish well before the sunrise, and you'll
need to compensate for earth's motion, with the help of a motorized
Equatorial mount...
...but meteors are unexpected: nobody can know where or when will appear.
And they are quite ephemeral, typically lasting half a second or so. And
despite being rather bright, they move quickly across the sky, so the long
exposure won't integrate much light on a single point of the film.
To make things worse, they behave like point-like sources, so the only
factors on exposure are the film speed and the _absolute_ aperture -- the
f-number is no longer valid! That means that a 85/2 (with its 42.5mm
entrance pupil) is better than a 50/1.4 (35.7mm pupil) but covers much less
of the sky, so it has much less chances of catching a meteor... unless a
larger amount of cameras is used :-(
You are going to use a lot of film, for sure; with standard lenses, a
typical set-up may need from 6 to 9 cameras in order to cover a reasonable
area of the sky. And no, a fish-eye covering the whole sky won't work,
because of the small absolute aperture (just 2mm in my Sigma 8mm F4) -- been
there, done that.
Film used shoud be as fast as possible, and so with the lenses -- another
reason to prefer 50mm's. If exposures are too short (no effect on recorded
meteors) you'll waste a lot of film; but with very long exposures, the
residual brightness of the sky (even in very dark places) will fog the frame
and wash out any captured meteor, so there's a limit depending on the speeds
of film and lens (this time _relative_, the usual f-number).
My best setup so far used combinations of f/1.4 @ 1600 and f/1.8-2 @ 3200 --
in order to make exposures of identical length in all cameras, otherwise I
would get crazy!!! In a very dark place (María, Almería, 1200m over sea
level) I could get exposures of about 5 min IIRC before film was fogged by
the sky... but then I spent most of the night visiting all the cameras (at
darkness!) in order to wind them, so I actually recorded _more_ meteors than
I could actually see with my naked eyes :-(
It's been a lot of time since my last meteor shower session, but now I think
a nice camera for it would be the ROBOT: a tiny thing from the 30's, with
motorized winding... by clockwork! That would need just the
electromechanical device ;-)
This little beast (intended for 1936 Olympics) can actually make bursts of
about 20 exposures at nearly 5 fps, if your finger is fast enough!!! Takes
standard 35mm film (in special reloadable cassettes) but in square format
(24x24mm), more than 50 exposures from a 36-roll. And interchangeable _fast_
lenses too: I have a nice Schneider Xenon 40/1,9 for it, beautifully made in
1959...
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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