Anamorphic Aspect Ratios

[Brandon S]

Just curious about the aspect ratios on a Red One and how it relates to using anamorphic lenses. I'm going to shoot out some numbers here and if i'm incorrect in any way just correct me, still learning a lot of this stuff. This all stems from someone wanting to use Lomo lenses which I understand are quite popular.
The Reds are Super 35 sensors which from the specs is 24.2mm x 12.5 mm. Now as I understand it anamorphics were used to squeeze the image onto a 4:3 sensor. I guess my confusions stems from how it's squeezing it onto a Super 35 sensor and if you're sacrificing pixel count, I imagine you would since there would have to be some cropping.
I notice there's a 4k ANA mode, does that give you equivalent aspect ratio recordings to the card?

 

[David Mullen ASC]

Standard anamorphic 35mm lenses have a 2X horizontal squeeze, so if the end goal is a 2.40 : 1 "scope" image for theatrical release, the area used for that image on the sensor will be 1.20 : 1. Any wider area of the sensor than that will ultimately get cropped down to 1.20 : 1 in terms of pixel ratio. Red 4K ANA mode records 2764 x 2304 -- the advantage with ANA mode is that you don't have to record more data than is needed for the 2.40 image (1.20 unsqueezed) plus it unsqueezes the image in the viewfinder.

 

[Rick LaLonde]

Thanks for the clarity, David. I've been looking for this info for two weeks. Any idea how much resolution is lost in the data reduction? It looks to me like this end up being less than 3K with the Red One sensor height being so short.

I'm also trying to figure out how wide of an angle I'll be left with using my Lomo 35mm square front after the crop to scope. Anyone know the answer to this?