Unreal Virtual Camera Matching¶
Lesson Plan
Match the settings of your real-life camera with Unreal for maximal realism.
The CineCameraActor in Unreal has a lot of settings that mirror real world cameras. Those settings when tweaked can affect the image.
Sensor Size¶
The sensor size has a large effect on the final image. A smaller sensor acts like a zoom.
A full-frame sensor with a 35mm lens:
The same camera and lens, but with the smaller Blackmagic sensor:
Focal Length¶
Focal length and sensor size offset each other. A smaller sensor acts like a zoom. In real-live photography a larger sensor produces a better quality image, but in digital cinema the sensor size has no effect on quality.
The Blackmagic MFT sensor with a 10mm lens:
A 1000mm lens, but offset with an equally large sensor:
As you can see, the images are identical. The longer focal length is offset by the larger sensor size.
Calculating¶
While it is possible to calculate the same image proportions with different settings, it’s far easier to match the virtual camera settings exactly to your real world camera.
The BMPCC4K Sensor Size is: 18.96mm x 10mm for 4K DCI (4096 x 2160). Since we are recording at UHD (3840 x 2160), it is a little narrower than the full DCI. We should calculate a new sensor size with the reduced width, but keeping the full height. So, our new narrower sensor width is:
The effective sensor size in UHD is 17.775mm x 10mm. We should double check this has the same aspect ratio as 1080p, which is the scaled down resolution sent over HDMI.
We are using a Metabones Speedbooster 0.71 with a Sigma 18-35mm lens (zoomed to 24mm). According to [CropFactorCalculator] our Focal Length with Speed Booster is 32.17mm.
Thus our virtual camera settins are:
Focal Length: 32.17mm
Sensor Size: 17.775mm x 10mm