how to get a 2:1 ratio from a Anamorphic x1,3 Squeezed lens

[Andres Rignell]

Hi!

I have a question about getting a 2:1 ratio from an Anamorphic x1,3 Squeezed lens.
What should be my settings in the camera? I´m going to work with a Sony Venice and shot in S-35 mode.
Does anyone have any experience doing this I would really appreciate the help.

 

All the best!

 

/Andrés

 

 

[David Mullen ASC]

Are you just talking about adding 2:1 frame lines? I don't think you can select your own sensor crop areas to record but you can create custom frame lines for composing and cropping in post.

 

https://pro.sony/ue_US/products/digital-cinema-cameras/venice#ProductSpecificationsBlock-venice

X-OCN ST/LT:

6K 3:2(6048 x 4032)*: 23.98p, 24p,

6K 2.39:1 (6048 x 2530)*: 23.98p, 24p, 25p, 29.97p

6K 1.85:1 (6048 x 3270)*: 23.98p, 24p, 25p, 29.97p

6K 17:9 (6048 x 3190)*: 23.98p, 24p, 25p, 29.97p

5.7K 16:9 (5672 x 3190)*: 23.98p, 25p, 29.97p

4K 6:5(4096x3432)*:23.98p, 24p, 25p, 29.97p

4K 4:3(4096x3024) :23.98p, 24p, 25p*, 29.97p*

4K 17:9 (4096 x 2160): 23.98p, 24p, 25p, 29.97p, 50p, 59.94p

3.8K 16:9 (3840 x 2160): 23.98p, 24p, 25p, 29.97p, 50p, 59.94p

In terms of recording format, to get a 2 : 1 image from a 1.3X squeeze, you'd need to use a 1.53 : 1 sensor area -- which is lucky for you since full-frame on the Venice is 36mm x 24mm (1.5 : 1). But that's assuming your 1.3X anamorphic lens will cover 36mm x 24mm.

So if your lens cover that much sensor, then if you simply recorded full-frame 6048 x 4032 pixels, you'd end up with a 1.95 : 1 aspect ratio once unsqueezed, which is very close to 2 : 1, so you'd just have to frame for some minor trimming above and below.

The camera does have a 1.3X desqueeze function for viewing.

If the lens doesn't fill 36mm x 24mm, then you'd want to create custom frame lines for the 1.53 : 1 sensor area (2:1 once unsqueezed by 1.3X) that can be used. If it is too much data to record 6048 x 4032, you'd have to work within one of the smaller recorded areas and crop that to 1.53 : 1 squeezed / 2:1 unsqueezed.

So create a 2 : 1 framing chart and put it in front of your camera with 1.3X viewing engaged and create custom frame lines to match and record it for post to know the area to be cropped for dailies, finishing... or create a 1.53 : 1 framing chart shot with a normal non-anamorphic lens (it would be the same.) My suggestion would be to create a 2 : 1 chart with a round circle in the center of the chart and "1.3X anamorphic / 2:1 AR" written under the circle so that post (and you) can tell when the image has been correctly unsqueezed to create a perfect circle rather than an oval.

I think you and your DIT are going to have to do some tests to work all of this out.

[David Mullen ASC]

I see you said "Super-35 mode" -- so which recording option are you going to choose? Keep in mind that ideally it would be close to 1.53 : 1.

 

I'd consider trying the 5.7K 16:9 mode. 3190 pixel height is close to the height of 4-perf 35mm 2X anamorphic area (for 2.40 : 1) that they call 4K 6:5 (4096 x 3432) but if you used 4K 6:5 or 4:3, you'd end up cropping top & bottom because of the limit of 4096 pixels across. But if you record 5.7K 16:9 mode (5672 x 3190), then you'd be cropping 5672 across to 4881 across to get 1.53 : 1. Assuming that the 1.3X lens will cover a 4881 x 3190 area, it might be slightly too large, you'd have to test.

 

Otherwise, you'd have to record one of the 4096 pixel modes and crop vertically to 2677 pixels -- so I guess 4K 4:3 would be the best choice, 4K 6:5 uses more height than you need and 4K 17:9 mode uses less than 2677 pixels vertically.