RE: [APML] Piggyback 4x5

["Jeff Ball" <jeffball@zoominternet.net>]

Thanks to Kirk, Chris, and Joseph for the info.

My friend does have the Cambo camera.  I am looking at using a 90 f8
Schneider lens.  I was thinking of Provia 400.  I have a lot to learn and
will get back as questions arise.  Thanks again.

Jeff Ball
www.astro-photography.com

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Kirk Carbo
Sent: Monday, May 12, 2003 12:35 PM
To: 'astro-photo@seds.org'
Subject: [APML] Piggyback 4x5


Jeff,

I piggy backed my Cambo 45SF at the Texas Star Party a couple of weeks ago.
It is a monorail camera design.  I locked all of the movements as tight as I
could before the exposure and I didn't see any sign of flexure.  I used a
135mm Schneider lens wide open f5.6 for 60 minute exposures on Ilford HP5.
The film has some red response and Robert Reeves told me he used it in the
past and he didn't find the reciprocity failure as bad as some have
reported.  The stars start to look bad around 4 inches from the center.  I
only made two exposures as an initial check.  I am encouraged though.  The
image circle of the 135mm at 5.6 just barely covers a 4x5 negative, so I am
hoping a lens with a larger circle will have stars sharp to the corners.
Next time out I will try the 210mm (image circle 252mm at f5.6) and the 90mm
(image circle 201mm at f5.6).

The other issues for me were focusing and composition.  I was able to get a
good focus on the ground glass with a loupe, but forget about seeing what is
in your frame.  I will have to rig up some kind of an external framing
device like the old press cameras had.

Kirk Carbo
Lobo's Services
Ph: 800-225-0899
Fax: 225-677-8277

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