Distortion Grid Chart

SKU: DISTCHART
23,00 €
excl. 19% VAT , plus shipping costs (Standard)

A simple tool that helps VFX professionals to unwarp the image and to better stabilize motion within shots for a further VFX integration.

It’s basically a checkered board with a clear central point and strictly straight lines.

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Delivery time: 3 - 4 Workdays


It comes in different sizes and varies in composition of checkers (which you’ll see below), but one main principle remains: the distortion grid must be big enough to cover the whole frame during the shooting.

How to line up a lens grid:

  • Lining up a lens grid is a two-men job. The board with the grid must be set up on C-stands, light stands, or any equipment with adjustable height, so it’s plumb and faces the camera flat. To prevent tilting of the board, use an inclinometer or a spirit level to align the grid strictly horizontally.

  • At the same time, the camera must be as perpendicular to the grid as possible. If you have multiple positions to shoot the grid from, it is better that you place the camera on a dolly track to facilitate a fast movement through positions. To be certain that the camera is not leaning anywhere, you can use a spirit level for it just as you did for the lens grid. Or, if your board has an XO element on it, just line up the camera viewfinder with the XO.

  • Last but not least, light up the grid nicely, so it doesn’t have shadows or flare. Make sure that the grid looks sharp and focused within the frame, and you’re ready for the next step!

Different types of lenses warp and distort the image in their own unique way.

Shoot the grid entirely filling the frame at the T-stops that will be used during the production. Use a dolly to move through positions that will be used during the production, too. It is important that you use the same lens, the same environment, the same focal length that is intended for the actual shooting of the film.

Another extra-important step: slate every take with any parameter change, even if you change the body of a camera. Here’s what should be documented on a slate at all times:

 

  • Lens type and serial number
  • Camera body
  • Focal length
  • T-stop
  • F-stop
  • Focus distance
  • Distance from the grid to the camera

Reslate for each position, exposure, and focus change.

Manufacturer: prisma.film
Category: Set appearal & Equipment
SKU: DISTCHART