Using ND filters for EFP

[Bob Franco]

I'm wondering if anyone has figured out how they are going to approach EFP style shooting they may be doing now with a Sony/Panasonic camera, with the Red camera. Today I was shooting with my Sony and switching ND settings frequently as well as iris setting using the camera's auto iris to get me in the ballpark and adjusting how I wanted it. I'm used to doing it and it is done very quickly. I'm thinking that with the Red camera and Nikon or Canon lenses, I would probably have a heavy ND filter screwed into each lens and have another filter in the matte box, as needed. Or maybe the other way around would be faster. Due to the wide dynamic range of the camera, maybe I could be a stop or more under or over and still get a very good picture? Anybody have any ideas on how they will address the ND and iris settings in a fast moving shooting scenario?
Bob

[Ken Corben]

"Fast Moving Scenario" is the buzz term. I've been kicking this one around a bit based on Red's 500 ISO rating and the 11 stops of latitude with the "half under" practice from film.

Who's to say really until it is field tested - even then, the operators will have personal choices/opinions. I am thinking screw on ND filters for single operator, fast moving, hand held with out a matte box. Why?

Well if I am using an ND 2 in daylight I'm ISO 125 at 1/48th sec exposure and living in f-stops where critical focus won't kill me as it would below f5.6, no? Also, hand held with a matte box that covers 16:9 is wieldy and I'm used to having a first and second AC to reduce the workload. It may take a few seconds more to screw and unscrew ND's rather than dropping them in but the lighter load for fast moving hand held is the deciding factor.

If I am on sticks for an "event" then the reverse is true and I have the luxury of an assistant and matte box is the way to go.

Of course this is just thinking out loud - Gibby and I are going to test these theories to the max in order to develop a tried and true working system for any given application.

Sharky

[Bob Franco]

Mel,
I guess we'll know when the camera is in the hands of people who will disover the Red production "work flow". Maybe one way to go would be to use series 9 filters with one of the large rubber lens shades... that could be a solution for one man crews. However, if you can adjust the ISO rating maybe it's not as big a problem as I think.
Bob

[tj williams]

Maybe in a run n gun situation it will be easier to just shift the EI on the camera, than change filters. So we'd put up ND for the brightest part of the shoot and increase camera sensitivity by a preset button bump, for the lowest light levels. When you look at the posted images with very high EI set on the camera it's pretty amazing the crispness of the blacks!

[Unwounded]

So, just curius, why did red choose not to go with a filter wheel? Even high end cameras like the viper and F23 have filter wheels. Was it for overall cost savings (so they could make the 17,500 price point like what they did with the CF module)? Was it engineering spatial concerns? Or something else.

[chuck colburn]

So, just curius, why did red choose not to go with a filter wheel? Even high end cameras like the viper and F23 have filter wheels. Was it for overall cost savings (so they could make the 17,500 price point like what they did with the CF module)? Was it engineering spatial concerns? Or something else.

Morning Unwounded,

One reason I can think of why not to use behind the lens filtration is that you always have to have one in place even if it's just a clear one. This is due to the fact that a filter even though it's flat (plano) acts like a positive lens element and will optically increase the flange focale depth (FFD) by appx. one third the thickness of the filter. For non back focus adjustable lenses this can be a problem area as the individual filters would have to be matched for thickness to a very precise degree. A .003" difference results in a FFD shift of .001" which would be unacceptable for a short focale length high speed lens. This is not much of a problem with video lenses with their slower speeds and you could always adjust the back focus anyways. Also there is the possibility of image degradation if the behind the lens filter is not optically perfect in all ways. This includes flatness, parallelism, proper surface coating and surface quality. So I think that the choice to not include a filter wheel is a wise one as who would want to take the chance of degrading a beautiful 4K image.

Chuck

[David Battistella]

So, just curius, why did red choose not to go with a filter wheel? Even high end cameras like the viper and F23 have filter wheels. Was it for overall cost savings (so they could make the 17,500 price point like what they did with the CF module)? Was it engineering spatial concerns? Or something else.

It had to do with the PL mount.

David

[chuck colburn]

It had to do with the PL mount.

David

Hi David,

I'm not so sure about that as the PL FFD is over two inches which leaves plenty of room for a filter wheel. It could be since the front of the camera is so compact and the S35 format is larger than standard video cameras that the filter size that would be required precludes the use of a filter wheel.

Chuck

[David Battistella]

Hi David,

I'm not so sure about that as the PL FFD is over two inches which leaves plenty of room for a filter wheel. It could be since the front of the camera is so compact and the S35 format is larger than standard video cameras that the filter size that would be required precludes the use of a filter wheel.

Chuck

Chuck,

You are correct on this. It would be a very difficult thing to incorporate without altering the entire design of the body.

David

[David Battistella]

"Fast Moving Scenario" is the buzz term. I've been kicking this one around a bit based on Red's 500 ISO rating and the 11 stops of latitude with the "half under" practice from film.

Sharky

I think some of Jim's indy images were exposed at 320ASA (not sure if you can gain this one stop with all production releases.

I think you are right about the run and gun. I still think a matte box could be faster if you had the filters in the holders on your person, sliding those in might be quicker than screwing them in. Also, it means new filters for every lens making the overall kit and what you carry grow.

Some are suggesting at least a three stage matte box because so much filtration will be needed in daylight and some of the ND's are harder to get in larger sizes. If I was a filter maker I would be pretty happy about RED as it definitely makes a Matte Box and ND's mandatory. Most EFP on 2/3 inch camera's relied on grads or pola's because the ND was taken care of with the filter wheel.


David