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Contrast Filter Grades
Published : 30th September 2003
In a few days time I'm shooting a video short film in Digital Betacam.
My main concern about excessive contrast comes in relation to day exterior
scenes (no lighting allowance). With a lot of luck I could be allowed
a couple of Ultra contrast filters to fight it back. In such situation,
which two grades of Ultra Contrast filters would be the best choice (from
1/8 to 5)?
Thanks a lot in advance.
Madrid (Imperial Spain)
There are limits to how much any filter is going to improve shadow detail
in any meaningful way, so the UltraCon isn't some cure-all or substitution
for fill light -- but it will help lift out shadow information that is
just slightly being buried. Any more than that and all you are doing is
lifting the blacks.
Luckily since you are shooting video, you do have the option to color-correct
in post to match black levels shot-to-shot if you over-do the UltraCon
strength. You really need a couple of filters in a set, maybe three, because
of the filter reacts to the amount of light in the shot and the amount
of ambience hitting the glass. I'd probably try a #1, #2, and #3, with
the idea that you might have to restore your blacks in post if needed.
Watch out for pointing the lens into a big light source because the image
will get milked out unless you switch to a lighter grade.
Cinematographer / L.A.
Much of what an UltraCon does can be mimicked by adjusting the Master
Black (aka pedestal) and the Gamma in the camera. You can always pull
these down again in post.
>Much of what an UltraCon does
can be mimicked by adjusting the >Master Black (aka pedestal)
and the Gamma in the camera. You can >always pull these down
again in post.
I would question the assumption that adjusting the Master Black (aka pedestal)
in a video camera actually gives you more detail in the black. My experience
is I do not see any further into the shadow it just takes the black and
turns it grey (It might allow you to see more into the shadows on a misaligned
monitor that was already crushing the blacks). I suspect if you shot the
same scene with the standard setting then with the black lifted then corrected
in post the two shots would have identical black detail.
I would imagine changing the gamma settings would be more productive.
I qualify these statements as I have not done controlled tests so please
prove me wrong !
Tom Gleeson DOP
Arturo Briones Carcaré wrote :
>which two grades of Ultra Contrast
filters would be the best choice (from >1/8 to 5)?
David Mullen has a good handle on the uses of the Ultra Contrast, to which
I'd like to add a little. In terms of selecting a grade, as a special
effect, anything goes from very mild to extreme. In this instance, though,
for fine-tuning shadow details in what sounds like bright sunlight, its
best if the filter only adds slightly to the luminance level of the shadows-
this allows more detail to appear that otherwise might not, and avoids
additional lightening that might border on appearing washed out without
rendering the benefit of more detail.
Without knowing the actual circumstances, it isn't a sure thing to make
a grade guess, but I would suggest that you try using the 1/4 and the
1, as they are mild, yet strong enough in bright sun to register. Make
sure that ambient light is allowed to hit the filter- this is what sets
it going. As David has said, be aware that if you pan the camera toward
a bright area, the filter will have a greater effect than it will when
facing a darker area-panning continuously from brighter to darker can
make a visible change that may or may not enhance the story. Best to know
Test where possible.
Good luck with your shoot!
The Tiffen Company
Hauppauge, NY 11788