VFX Bugbears – 001


Now this is going to be quick. I know, not something you hear come out of me at all. It is going to be quick though. I occasionally come across things in my job that drive me barmy. Generally it’s stupid things like people on their phone in the fast lane of a motorway (seriously, you are risking your life just a bit!) or the number of disposable masks littering our streets now (put it in a bin!) that sort of thing.

But sometimes, they are VFX or 3D things. Things that people seem to do despite knowing it’s not right. Or basic errors that would never happen in the real world. I’m not talking about missing a shadow. No, I’m talking about practical things that are fundamentally incorrect.

And this one I see ALL THE TIME!

(sigh..)

So, here’s the thing. If I was to ask you the shape of a lens that fits to a camera, you know, the thing you actually screw into the body, what would you say? What shape is that?

Well, yes, it is cylindrical. It has to be to have room to fit in the lenses. But what do we know about a cylinder? It has three sides, yes? Yes. A tube body and two…come on…you can get there…

Two circles. In fact it is the edge of the casing of these circles that manages to stop a little light reaching the corners of the pictures. So if you are taking a landscape through a lens, you’re light will be diminished in a circle…

…even if you are shooting through at HD, the lens and it’s housing is still round.

So why, oh why oh why, do people still keep doing this for a vignette?

No! No, no, no, no…

Your camera does not have an ellipse for a lens. I has a circle, so the light, even when there are gates on the camera front, still has a circular vignette. This ellipse thing is so wrong. Do not do it.

QUICK TIP:

Make a circular mask on an adjustment layer or color corrector, set it to be subtractive, feather or soften it’s edge and add an small negative exposure shift. Nothing fancy, just a little bit. But there should not be any of that at the top, unless you want to give the impression you cropped your image from the top down, then shift the circle mask down until it touched the top.

Stop using ellipses. Please.

Bugbear 001 over.


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