Anamorphic Desqueeze on Black Magic Video Assist 4K

hans anamorphic copy.jpg (72.43 KiB) Viewed 4895 times

So i have this problem:

I appreciate the firmware update 2.5 for the video assist!

love the very fluent waveform monitor.

also the anamorphic desqueeze was a lifesaver for me.

BUT but but....

the 2x anamorphic desqueeze actually stretches the image out to left and right,
so i'm only seeing half of the image!
i am using a 16:9 source, so i would end up using about 70% of the width of a 2x anamorphic stretched image.

Hans, which camera is supplying the video? Do you have the option to shoot in some other aspect ratio? If your video source must be 16:9, the 2x anamorphic lens gives you a 3.55:1 aspect ratio which is very limited in its usefulness although it has its fans. If you used 1.5x anamorphics, your aspect ratio would be a more acceptable 2.66:1 which is more common than 3.55:1. But if your goal is 'widescreen,' then your anamorphics need to be 1.33x paired with the 16:9 recording.

If you only have 2x anamorphics, the ideal option would be the 3K Anamorphic window 3072x2560 on the 4.6K sensor that will give you 2.4:1 widescreen.

If you're on a camera that has a 4:3 aspect window, shooting 2x will get you to 2.66:1 and you may like that or crop it modestly to a widescreen aspect ratio.

I don't have the BMVA4K, but it looks like it requires HD or UHD so perhaps not the best solution for 2x anamorphics.


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I'm not an expert here, but I do shoot anamorphic 2x from time to time. Traditionally 2x is when you're using a open gate or 4:3 image size. Stretched 2x into 2.4:1. Shooting 1.33x on a 16:9 image would do the same and create 2.4:1. I think since your image is stretching to 32:9 ratio it might not be considered standard for viewing on the monitor.

EDIT: Sorry, I didn't see that Rick responded w/ this above.

No problem, Aaron.

To clarify: When you start with a 4:3 sensor or window, the 2x anamorphic will give you a 2.66:1 aspect ratio which is often then cropped to widescreen 2.4/2.39:1.


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Okay Hans, I'm with you now. I just got the 4K assist and tested 2x anamorphic mode. It's only showing 70% of the image on mine as well. I'm feeding a 4:3 image from GH5 with a 2x anamorphic prime. Desqueeze works but it's cropping off the sides.
I have the exact opposite problem on SmallHD where it scales too much and adds black bars on the side. Weird.

Hans' original markup image shows the 2.4:1 frame and the visible area on the BMVA4K. That visible area just looks like it's 16:9 aspect ratio which is the display area of the VA monitor. Can you drag or swipe left and right to reveal the obscured parts of the 2x desqueezed image?

If the image is all there when you drag left and right, does a double tap reveal the whole 2.4:1 or 2.66:1 image?

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Rick, no unfortunately. I was looking for some kind of scale down command.

I ended up returning it and getting the Atomos Shogun Inferno. It displays full 2x, slightly lighter than the VA4K, and 3x brighter.

I've seen that demonstrated with 2x desqueeze so that's important to you. Not sure why that's not functioning on the BMVA4K. Extra bright very nice.


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Ok. So, what's the rationale between enlarging the anamorphic image horizontally instead of compressing it vertically? I just got an used Video Assist 7" 4k and although there are many things I like about it, I can't wrap my head around the point of the anamorphic desqueeze. Is it meant only for the ursa line of cameras?
I haven't updated the firmware to the latest version, but I imagine it will be the same.

I honestly would like to know from anyone at blackmagic why their anamorphic desqueeze works in that way.

Thanks

Choose your poison. The SmallHD with the black columns right and left may be squeezing the vertical dimensions to show square pixels on the monitor. BMD seems to expand the horizontal dimension to square pixels. It always displays my images on the camera properly but my BMVA12G7 has not arrived yet so I can’t verify the Video Assist 12G will handle everything. I can test next week.

In post, in Resolve, I always squeeze the vertical axis to get back to square pixels rather than expand the horizontal axis. That way the deliverables playback properly (letterboxed) on a television for example.