Anyone using 85B nd filters w R1?

[Anthony Gratl]

I've got an opportunity to purchase some filters at a very good price....does anyone use the 85b nd filters? Are they worth purchasing for a digital system?
Any recommendations for filters in general to purchase, outside of the obvious polarizer and hot mirror/ir ?
I'm thinking along the lines of coral, skylight, and fog and diffusion filters....the pro mists are all gone...but i'm thinking of a few tobacco grads as well? Thoughts?
Thanks in advance

 

[Evin Grant]

Avoid the 85B filters they are taking you in entirely the wrong direction color temp wise.

 

[Anthony Gratl]

thanks evin....the 85's are fine though correct?
Also, any thoughts on the other filters?
I guess my question is also whether to use more filters on set as opposed to
cc afterward...such is the digital RAW dilemma no?

 

[Shawn Bannon]

85's are for correcting tungsten balanced film to daylight. Since the Red is a daylight balanced sensor there is no need for the 85 filters.

 

[david farland]

As a general kit, I hire out the following..........

Schneider neutral density x 6 - ND 0.3; 0.6; 0.9; 1.2; 1.5; 1.8 - (4"x 5.65")
Schneider grad ND (soft edge) x 3 – ND 0.3, 0.6, 0.9 (5.6"x 5.6")
Schneider grad ND (hard edge) – ND 0.6 - (5.6"x 5.6")
Schneider Optical clear – (5.6"x 5.6")
Schneider Tru-Pol Polariser (138mm round)
Formatt Infra-red filter (4"x 5.65")
Tiffen 80D correction filter (4"x 5.65")

These filters are used in an Arri MB20-II w/ 3 stage filter box with three (4"x 5.65") filter trays and two (5.6"x 5.6") filter trays.
Filters I'd add would be a 80B & maybe a drop-in polariser.

The next filters I'd like to get would be various 'spot' grads but I don't know if they make them (or if they really work).

Dave,

 

[Dan Hudgins]

warm vs. cold

warm vs. cold

The only warming filter I can think you would need might be a UV/skylight for shooting in open shade from blue sky, the other filters would be 80 series bluish for shooting under tungsten lights, and maybe a FLD for shooting under florescents. Maybe an XB29. An 81EF can be used to warm daylight/skylight sources, but anything that orange may add some blue noise, you can make things warm in post by adjustments to the blue and green gammas.

 

[Pawel Achtel]

81EF can be used to warm daylight/skylight sources...

Yeah, I use 81EF on overcast and mid-day sun and it works well to bring all RGB closer together.

Pawel

 

[Daniel Browning]

Magenta for greater dynamic range, lower noise, etc.

Magenta for greater dynamic range, lower noise, etc.

Many outdoor scenes have the green channel one stop higher than blue/red, sometimes as much as two stops. A magenta filter knocks down the green channel allowing you to add a little more exposure (ETTR) because the histogram is lined up better. With a higher exposure comes lower noise and more dynamic range. Not useful in low light, of course.

Here's a good thread on filters from a still photography forum: http://forums.dpreview.com/forums/read.asp?forum=1018&message=29592761

 

[Dan Hudgins]

x CC-M

x CC-M

Many outdoor scenes have the green channel one stop higher than blue/red, sometimes as much as two stops. A magenta filter knocks down the green channel allowing you to add a little more exposure (ETTR) because the histogram is lined up better. With a higher exposure comes lower noise and more dynamic range. Not useful in low light, of course.

Do you have a with and without image? How many CC-M are you using, like 50CC-M (0.50 density?)

There should probably be a setting in REDCINE et al. for having the Magenta filter in front of the lens, or the sharpen might make some off color fringes, maybe?

 

[Daniel Browning]

Do you have a with and without image?

Iliah Borg was the first to share the idea with me; here's a web site about it:
http://www.libraw.org/articles/magenta-filters-on-digicam.html

How many CC-M are you using, like 50CC-M (0.50 density?)

0.30 density was just about right for open daylight on my Canon 20D. I haven't used one with my other cameras. I often find myself in a lot of outdoor situations where:

green is -0.3 stops from clipping
blue is -1.3
red is -2.6

A CC30M and one stop exposure here brings them closer:
green: -0.3
blue: -0.3
red: -1.6

Add a CC40R and another 1+1/3 exposure and you get:
green: -0.3
blue: -0.3
red: -0.3

There should probably be a setting in REDCINE et al. for having the Magenta filter in front of the lens, or the sharpen might make some off color fringes, maybe?

I'm not aware of anyone who has used the technique with RED ONE. I'm sure that some sensors and raw converters respond differently to minus green filtration (due to a different shape in the spectral sensitivity and demosiac). A color checker chart in the frame would be a good idea.

 

[Anthony Gratl]

thanks for the responses guys.....

Yeah, I use 81EF on overcast and mid-day sun and it works well to bring all RGB closer together.

Pawel

specific to this, which 81's do you use pawel? Anyone else doing this as well in other circumstances?

btw! happy obama america....not that i'm part of the cult of personality thing, but he sounds like he's on a reasonable track anyways....

 

[Dan Hudgins]

sensor bias values

sensor bias values

Iliah Borg was the first to share the idea with me; here's a web site about it:
http://www.libraw.org/articles/magenta-filters-on-digicam.html

Thanks for the info and link...

Shapen uses luma, so I think in REDCINE et al. there must be some white balance values to compensate for the sensors bias, when you use colored filters to remove that bias, the white balance values should be equalized, maybe, since we do not have true raw data it is hard to say what the bias comp is if any...

 

[Daniel Browning]

There must be some white balance values to compensate for the sensors bias, when you use colored filters to remove that bias, the white balance values should be equalized,

Agreed. The user-configurable white balance restores a natural white balance except for any reshaping of the spectral response caused by the magenta filter (hopefully very little).