Re: [APML]: Pro Kodac 400

["David B. Toth" <ve3gyq@amsat.org>]

At 10:13 PM 9/11/96 EDT, John A. Volk wrote:
>
><Since I own an AP 4"f6 and am considering to buy a 120 format camera, o
>ne =
>
>question: do you have a field corrector? Is it needed, or just a plus?
>
>Thank you!>
>
>Daniel,
>
>You absolutely need the field flattener or the images at the outer edges of the
>image will be very poor.  Without it you might as well use 35mm film.  You are
>at the mercy of AP as they are the exclusive maker of it at $395.  It also
>serves as a coupler to the Pentax 6x7, so you are limited to this camera body
>without a custom adapter.  The good news is that you will cover 5x the sky area
>compared with 35mm.  The telecompressor with 35mm camera gives you roughly 1/3
>the sky area of the 6x7. 
>

John et al:
You really need the field flattener even with 35mm film. I shot with the
Traveller at Ayers Rock and was forced to use the telecompressor, but even
that left a little field curvature. I have now bought the field flattener
and the 35mm adapter, even though I HAVE a Pentax 67, since I usually use
the 67 on my 7" while I run 35mm on the 4".

Haven't used the flattener yet, but discussions with Terry Dickinson lead me
to believe that I'll notice a big improvement.

As to being at AP's "mercy" --- a telecompressor or field flattener needs to
be designed for a specific focal length to give OPTIMAL results, especially
the flattener. The telecompressor doesn't give a fully flat field by itself
because it is a generalized design for use on all of their systems. It
usually isn't a problem for me, as I normally just use it for CCD imaging
(have both the .75 and the .5x telecompressors). I simply used the .75
telecompressor in Australia to try to flatten the field a little since I
lacked a flattener (BTW, the .5x is for CCD work only).

Dave

David B. Toth, MD
Eden, NC

ve3gyq@amsat.org

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