4K 16:9 gate size in mm?

[Cail Young]

A sticky situation this week in prep:

S35 ground-glasses for 16:9 do not match the RED ONE in 4K 16:9 - not even close.

I've often heard from DPs that the RED is tighter than the director's finder we've been using but never seen how much until this week.

So, does anyone know the actual dimensions of the recorded 4K 16:9 aperture? Because it isn't 24.4x13.7 (fairly sure that's the full gate including lookaround and black reference) and it also isn't 22.12x12.44 as iSee4K would suggest, as that's too close to the S35 value to be right.

 

[David Wyatt]

I'm not too up on all things related to format measurements (David Mullen is the undisputed king of these kind of things!), but isn't 3-perf Super 35mm meant to measure 24.89 mm x 14.0 mm, which is closer in size to the entire Red sensor (including look-around) which is 24.4 mm x 13.7 mm, as opposed to the actual recorded 4K 16:9 area (22.12 mm x 12.44 mm)?

Also I seem to remember Super 35mm commercials ground-glasses can vary slightly depending on which rental house you're at (I suppose it would boil down to Arri vs Panavision??)

 

[David Mullen ASC]

Yes, the Red recorded 16x9 area is closer to standard 35mm in size, not Super-35 -- you'd have to get the rental house to create a special groundglass for a lens finder, or just use a standard 35mm Academy/1.85 groundglass to line things up in 1.85 figuring it was close to Red's 1.78 area. I don't recall any groundglass markings that are 16x9 inside Academy.

 

[Cail Young]

The choice made for a recent shoot during prep was to use a 1.85 standard glass, so points to David Mullen yet again

I'll let the AC know, as he was very perplexed...

 

[Harry Clark]

I had a custom one made by Arri "Groundglasses On Demand", with the help of Phil G. at CSC New York, using the 22.12X12.44-ish size. It seems to be dead on.
It's the groundglass (435?) that goes in my Arri Media Finder.
If anyone wants one, I'm sure Phil still has the specs.
Cheers,
Harry

 

[Rainer Fritz]

http://dcs.co.at/pdf/REDFormats3.pdf

check this one

 

[Jason Wingrove]

Thanks Rainer, another chart for my collection
jason