|
Image transport, ULF film holders |
|
|
|
Monday, 23 August 2004 |
Film Holders are one of the parts of ULF photography that is a source of
headaches and worries. The need to be able to keep a very large sheet of film
very flat and within a light-tight environment is crucial.
 Film flatness is
very important because of the very thin depth of field (and subsequent depth
of focus at the film plane) that comes with using very long lenses. The need
to keep the film in a light-tight environment is evident, but for very large
holder, it poses technical problems that are not found in smaller formats
: controllong light leaks on a 5 inch length is not the same as over a 20-inch
span !
The only commercially available ULF plastic holder was until recently the
Fidelity 11x14 holder that isn't manufactured anymore. I guess it can still
be found as "new old stock", but at a price of around 150 $ each, they are
not cheap. Professionnally hand-made wooden holders are the only available
option for new holders on the market today, with at least 4 sources : Wisner
(www.wisner.com), Lotus View
(www.lotusviewcamera.at),
S and S, and AWB enterprises (www.filmholders.com).
All offer various sizes, but costs can be high, at around 300-500 $ per holder.
On the used market, holders can be found for the banquet cameras from Korona
and Folmer and Schwig, in sizes of 8x20, 7x17 and 12x20, but just be careful
what you buy, since the two systems are not interchangable. In fact, when you
buy a camera you must specify which holder you want to use with it so that the
back of the can be built to accept your holder. Camera builders often use this
reasoning of building the camera around the holder to ensure the best possible fit.
High film costs and holder costs often limit the number of holders ULFers have
on hand, and a ULF photo shoot is thus often only the 2 shots from a single holder.
I think it is worth it to invest in a good quality holder since that's what is the
first, last and only line of defense of your images against the ravages of light leaks.
But, if you are on a tight budget, it is possible to build your own, but you have
to be very careful with the film plane depth of the holder, which is the single most
critical measure for the whole project and has to match to within fractions of a milimeter
with the position of the ground glass when the holder is removed. |
|
Last Updated ( Monday, 07 November 2005 )
|
