Widescreen Options on the BMPCC4K

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rick.lang

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Widescreen Options on the BMPCC4K

PostMon Aug 20, 2018 6:21 pm

I’d appreciate your learned opinions regarding the options that we may have to achieve a widescreen aspect ratio on the BMPCC4K. For my purposes her widescreen could mean either 2.4:1 or 2.39:1 or 2.37:1 or 2.35:1 since a minor crop will get any of those to your desired aspect ratio for your deliverables.

With most BMD cameras that have an open gate in a 16:9 aspect ratio, it’s easy to either add a 1.33x anamorphic adapter or lens and get a 2.37:1 aspect ratio. The major benefit of that is using all the sensor’s lines of resolution. There is a financial cost though in adding an adapter and a large cost in using anamorphic primes. The low budget alternative I have used to date is simply cropping a 16:9 frame to 2.4:1 in post. No cost but you lose about 25% of your lines of resolution. For example going from 4608x2592 to 4608x1920 in the URSA Mini 4.6K camera.

That’s the straightforward choice for most BMD cameras. However the open gate of 4096x2160 presents a new situation. And not having an economical 2K recording option as found on the URSA Mini 4.6K is an additional wrinkle. There has also been no statement from BMD if the production version of the BMD will support in camera downscaling of ProRes from 4096x2160 or if it will be from 3840x2160.

Shooting 4096x2160 and cropping in post to DCI 4K 4096x1716 or cropping and downscaling to DCI 2K 2048x858 is easy. The resolution loss is over 20% going from the open gate 1.89:1 to 2.39:1 widescreen frame.

But for those who may use an 1.33x anamorphic lens or adapter, it gets complicated and costly. If you used the 1.33x anamorphic on the 3840x2160 16:9 window, at least the math is easy and you end up with 5120x2160 for a 2.37:1 ratio. With no loss in lines of resolution and a gain of one third in columns. But I don’t think you’ll deliver 5120x2160. Downscale to 4096x1728 and crop to DCI 4K 4096x1716. Or downscale to 3840x1620 2.37:1. You end up with the same deliverable resolution with perhaps slightly better edge detail or colour or no perceptual benefit to offset the cost of the anamorphic.

Now if you shoot open gate with the 1.33x anamorphic, you’ll have the equivalent of 2.5:1 5460x2160 footage and you’ll likely cut that back to 5120x2144 or a deliverable 4096x1716 or 2048x858 in post. So it looks like there’s no advantage of shooting open gate and getting the widest angle of view unless you’re willing to live with a non-standard 2.5:1 aspect ratio: 5460x2160 or 2730x1080 or a deliverable 2048x810. The biggest advantage though is that the horizontal angle of view of your frame virtually matches the URSA Mini 4.6K open gate.

But if angle of view is the major goal, using the SpeedBooster is less cost and increases the vertical angle of view as well, however without the anamorphic ‘look.’

What would you do? Go with an anamorphic (A) or SpeedBooster (B)? All of the above (A+B)? Just shoot spherical lenses open gate, crop in post (C)?


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Denny Smith

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Re: Widescreen Options on the BMPCC4K

PostMon Aug 20, 2018 6:43 pm

I would go with B or C, not an anamorphic fan, depending on the lens choice, of course.
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rick.lang

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Widescreen Options on the BMPCC4K

PostMon Aug 20, 2018 8:09 pm

I’ve been working on A but when it gets down to the nitty gritty of selecting frames and potentially extra workflow, it’s not looking as appealing as it should. The 1.33x anamorphic adapter would work better on the URSA Mini 4.6K due to its 16:9 open gate. But compromised on the BMPCC4K 1.89:1.

But the URSA Mini 4.6K has that 4608x1920 2.4:1 window anyway with no fussing in post.

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John Paines

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Re: Widescreen Options on the BMPCC4K

PostMon Aug 20, 2018 8:23 pm

Anamorphic can be quite challenging for a one-man band -- focus, for one thing.

Resolution differences between the 3 methods will be imperceptible in moving images, and I don't think you can assume anamorphic would yield more real-world clarity (more likely, the reverse). What you do lose by cropping is the unique look of the anamorphic "bokeh". But cropping makes life for the shooter much simpler.
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rick.lang

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Re: Widescreen Options on the BMPCC4K

PostMon Aug 20, 2018 10:02 pm

Thanks, John. The anamorphic bokeh of the 2x lenses is quite stylish, but it’s subdued on the 1.33x. Same with the streaks and the edge distortion. I have to think about the real benefits on the URSA Mini 4.6K, but I don’t want a degraded image on the Pocket4K. When I get the camera, I’ll test a transcode of raw open gate in post to DCI 4K widescreen 4096x1716 and a post downscale to DCI 2K widescreen and HD widescreen versus ProRes full UHD downscaled to full HD in camera and then cropped to HD widescreen. That will let me see if “bigger is better” or “how you use it that counts.”
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Lee Gauthier

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Re: Widescreen Options on the BMPCC4K

PostThu Aug 23, 2018 3:54 pm

FWIW, both Spielberg and Cameron, who can shoot on whatever they want, have both given up anamorphic for spherical with a crop. As pretty as the bokeh and flares are, anamorphic takes more time, and requires more light.

(Spielberg still shoots Indiana Jones anamorphic, but that's so all the films will match.)
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rick.lang

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Re: Widescreen Options on the BMPCC4K

PostThu Aug 23, 2018 6:23 pm

Thanks, Lee. I’d only be looking at the adapter so it’s true that focusing may be even more difficult and potentially impractical given I’m usually the sole operator.


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michaeldhead

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Re: Widescreen Options on the BMPCC4K

PostThu Aug 23, 2018 10:08 pm

Lee Gauthier wrote:FWIW, both Spielberg and Cameron, who can shoot on whatever they want, have both given up anamorphic for spherical with a crop. As pretty as the bokeh and flares are, anamorphic takes more time, and requires more light.

(Spielberg still shoots Indiana Jones anamorphic, but that's so all the films will match.)


It's my understanding that Fincher also shoots spherical and crops/reframes as desired.
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rick.lang

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Re: Widescreen Options on the BMPCC4K

PostThu Aug 23, 2018 10:38 pm

Thanks, Michael. Three strikes and no balls in play! Team Anamorphic is in trouble.


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michaeldhead

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Re: Widescreen Options on the BMPCC4K

PostThu Aug 23, 2018 11:21 pm

rick.lang wrote:Thanks, Michael. Three strikes and no balls in play! Team Anamorphic is in trouble.


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For my part, I typically shoot full 16:9 with a 2:35:1 overlay, and in the edit I use a 2:35:1 letterbox overlay. It works for me when I want to shoot that way.

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