Correct anamorphic setup.

[LL_Will_J]

Hi Guys,

I am currently trying to figure out the correct setup for rendering with an anamorphic plate. I have footage shot on red dragon with an anamorphic lens. This gives me a pixel aspect of 2.

So far I have the settings shown in the image. Seems to work great! Very happy with how its working.

My only question is can I change the the meta data that is written to my EXR? Currently its not picking up that I want my pixelAspectRatio to be 2 (its currently set to 1).

Is there anyway to change the meta data? Or is it something wrong in my settings?

Thanks in advance!

Will

[Rens]

As a side note, if you'll be scaling the image height down by 2 for 1:1 pixel aspect output at the end, it usually makes sense to render 1:1 and then uprez in nuke to pixel aspect 2, and then scale it back down with the plate again. You won't notice the difference and it'll save you half the render time. : )

[LL_Will_J]

Thanks Rens, Glad I posted this at the start of the project! Need to look into your tip. Half the render time sounds nice!

Will

[joconnell]

Working on a job with the same image size and camera, fucking hell the frames are slow - bad that with the debayer that lots of the data in the image is invented too making it a "not really" 6k image and us having to deal with overheads!

[t.petrov]

What version of V-Ray are you using?
Until recently we weren't storing the pixel aspect in the EXR metadata.
But we're doing it now in the night builds.

[LL_Will_J]

We are currently still on Vray version 3.1. Good to know that its in the meta data for the most recent verisons.

But actually I have now taken Ren's tip and we are rendering it to the half height resolution. I did a direct comparison of the ''correct'' anamorphic setup I previously mentioned and the half resolution in the height (with a pixel aspect of 1). The difference is very subtle - so halving the render times was too good to pass up!

Cheers for the tips.

Jconnell - Yeah. We just finished a really similar job to the one we are doing now that was shot on Alexa. The compositors are really complaining about the Red footage in comparison.

[Rens]

Great, glad it helps!

[LL_Will_J]

While I have the ear of you guys. Does anyone have knowledge of how anamorphic lenses compare to their spherical equivalent?

I have read its x2 on RedUser (ie an anamorphic 35 is approximately a spherical 18mm). I am getting some funny FOV from shots tracked in Nuke. If I let Nuke automatically calculate the lenses it gives a number around half of the ''known'' value I have - this kind of confirms the idea of anamorphic being x2.

But I cant find anywhere that really confirms this as a fact.

Many thanks

Will

[VISUALMAN_TOKYO]

Yes you are correct, anamorphic lenses 2x capture twice wider but squeeze the image to fit into a 4:3 film or sensor. The image height is equivalent but width is twice once unsqueezed. Maya camera can be set to capture a wider image by using the Lens Squeeze Ratio and in the viewport you can properly set the right field of view of an anamorphic lens. Unfortunately I found that Vray ignores this parameter so there is no way to render the same fov. So the only way to match the real lens fov is to use twice the value in the camera aperture width. This trick works well also for tracking in nuke.