Camera Sensor SizesTo properly calculate the location of the virtual camera, Previzion uses the physical dimensions of the camera being used. Some cameras rate their sensors as “Super 35″ or “2/3 inch” but these often vary enough that every other camera will need their own Sensor Width (in millimeter).
To set the camera sensor width, use the drop down menu in the Camera Sensor. Once selected, you will see the Width (mm) setting change accordingly.
A number of common camera sensor sizes are already included. At present, Previzion assumes a 16×9 sensor width ratio, although this will be expanded to handle new types of images. If you are using a RED Epic in 5k full-frame or an F65 in full frame, the aspect ratio coming out from the live HDSDI output will actually be in 17×9 aspect ration where the top and bottom of the image is letter-boxed.
The camera sensor width can be adjusted interactively by clicking on the value and entering a new number, or by clicking in the value box and dragging upward or downward. For finer grained control, hold down Control while clicking and dragging. To save a sensor width, click Save Width.
Creating a new Sensor WidthTo create a new sensor name, click New Sensor.
Enter a description in Sensor Name and adjust the width. Select “Save” when done.
The sensor setting will be saved in your Previzion system state. If your system state is reset or you load a system state that does not have your custom sensor sizes, the new sensor size will be removed.
To delete the current sensor width, click Remove.
Calculating Camera Sensor WidthThe best way to properly calculate the sensor size is to either look up the detailed technical specifications of the camera being used. In some cases it is better to request directly from the manufacturer, or knowledgeable source, the correct pixel pitch.
Pixel Pitch is the actual spacing between each pixel and it is measured in micrometers(µm), or microns. For our purposes we can assume this as the “pixel size.” Once you have this measurement, you can calculate the proper sensor width by multiplying it by the width of the pixels being used. For example:
- in a RED Epic, the pixel pitch is 5.4 µm (or 0.0054mm)
- at “4K 16:9,” the number of pixels actively capturing light is 4096 px by 2304 px (width is 4096 pixels).
- pixel pitch * horizontal pixel count = Camera Sensor Width
- 0.0054 (px/mm) * 4096 (px) ≈ 22.12 (mm)