Dynamic/Graduated Desqueezing

[Caleb Genheimer]

Hi, all! I'm trying to figure out how to get the most out of my anamorphic, and I've noticed that the squeeze ratio across the frame with my Kowa 16-H is not consistent. A straightforward 2X stretch works perfectly for desqueezing the center of the image correctly, but towards the left/right edges of the frame, the image gradually becomes more compressed even than 2X, causing it to look compressed at the edges even after the footage is desqueezing.

Has anyone ever done a dynamic/graduated desqueezing with varied adjustment of the desqueezing across the frame? Any ideas how to do this?

[valid]

yeah. the problem is not the desqueeze itself - it's the lens distortion of the anamorphic. It's quite a pronounced sphere at the edges, so they become 'compressed' more, if that makes sense? Depends on what software you are using, but I've had good results (not perfect but close) in Nuke - using a checkerboard grid that I filmed as a calibration tool, and then re-straightening it...

[Caleb Genheimer]

Yep, exactly what I was asking about, thanks! I was even filming checkerboards yesterday while trying to sort this out. Of course I don't want to completely flatten out the lens barreling, as that's one of the trademark traits of anamorphic, but this goes beyond average barreling along the far edges, it really is a squeeze ratio thing. It is very obvious when panning especially.

So I guess only advanced graphics programs will be able to do this? I'll have to dig around some more. 

[richg101]

if shooting raw, you can use the lens correction on adobe raw before transcoding. you'll need to work out the distortion of the kowa for each taking lens focal length.

 

expect around 15-20% distortion at the edges when using the kowa (or most 2x anamorphs) with its widest taking lens. 

[Caleb Genheimer]

I'm on NX1 at the moment, probably will be for a while yet as weddings are my main bread and butter, so no RAW unfortunately. I've got some whiz-kid computer friends, perhaps they can whip up another  converter solution or a plugin or something.

[Hans Punk]

+1 for shooting a grid, then correcting from that result. It is probable that you have to adjust correction for different taking lenses. Nuke would be most proficient for correction like this, but After Effects would work too - using the optic compensation tool (inbuilt into AE) and/or some custom warp tweaks.

[dhessel]

Just in case you didn't already know but the Kowa is only 2x at infinity at its closest focus it is more like 1.7x. I am not sure if the how the breathing affects the barrel distorion but I wouldn't be surprised if the distortion varies as well.

[Caleb Genheimer]

Yep I'm aware of that, but with the Rangefinder, it stays at infinity, so the changing squeeze with focal point doesn't happen.

[valid]

On a side note - how are you finding the rangefinder with the Kowa?

[Caleb Genheimer]

Simply amazing. I know there's been a bit of hullabaloo about Rectilux vs Rangefinder, but I'm shooting 4K on NX1, and the Rangefinder holds up great. It's actually my taking lenses that I'm finally starting to give more thought to, now that I can focus the darn thing.

Does anyone know if Apple's Motion could do this desqueezing stuff?