[Leica] Gigabit film

["Erwin Puts" <imxputs@knoware.nl>]

I am analysing this film since several months and have to admit that it is a
daunting task. I also have to say that the emulsions as distributed by the
manufacturer for its 35mm version are not yet the final commercial version.
So variations in batches (speed and other characteristics) can be expected.
One should not draw too hasty conclusions based on the fragmentary results,
published on the Internet.
My initial comparisons do show this film to be ahead of both APX25 and TP.
Grain of the Gigabit emulsion is even finer than TP. The  characteristic
curve of the Gigabit has a quite low CI value and this at the moment needs
to be addressed as the imapct of the prints is on the soft side. I made a
series of prints at 30x40cm and all observers assumed the prints to be from
a medium format camera. At this scale the definition of extremely fine
detail is so high that even higher enlargements would be needed to get all
detail on print at a resolution level that the eye can detect.
A technical discussion of this film has to wait, but a few observations are
interesting. The DoF calculations are based on  3 to 5 times enlargement and
when you magnify at 15 times the true DoF is reduced by a factor of 3 to 4.
I shot my pictures at 5.6 to get a bit DoF, but at this magnification the
real DoF is reduced to 2.8!! That is the depth of the sharpness area is
reduced to a small width. This is logical: as you enlarge more, the circle
of confusion is enlarged too and becomes visible for the eye, where at
lesser magnifications the CoC is below the threshold of vision.
The sharpness plane then is reduced in thickness and in itself enhanced in
quality. The unsharp zones are relatively more pronounced and the focussing
errors become much more visible too. At the enlarger stage you see the same:
any focssing error does reduce the perceived quality immediately.
It does not make sense to use the Gigabit film for small magnifications and
at prints below 20x25cm much of the special properties of the film can not
be exploited. The film excels at 30x40cm prints and here too we see the
inherent image quality of the current Leica lenses.
When you are walking around on this level, you are becoming painfully aware
of any disturbing parameter, that you may have been taken for granted or did
not care about or thought would not exist. The film is really challenging on
the technical side, but also on the esthetic side as you need to consciously
select the topic you wish to photograph and the perspective and position.
There is much more to note about this film, but for me it is a fine
experiment to reconsider the state of my own technique and to reflect on the
subject matter that suits the film best and the way the M6 fits in.
But most importantly: handling this film is a sure way to feel really modest
about my own accomplishments and to refresh and reconsider my technical
basis. To be honest: I stumbled across limits I do not yet know how to
address: but that is challenge, is it not?
A film that needs a workshop to explore and discuss.
Erwin