Sun Apr 26, 2015 6:51 pm
The smaller sensor of the BMCC does not change the "focal length" of a lens, a smaller sensor changes the "Angle of View" only, so a 25mm lens gives a 45-degree angle of view (normal lens look) on the Cinema camera, where it would be a wide on a larger sensor. Take a piece of paper with a picture on it, and draw a 2-inch circle on it, the area a given lens covers. Then draw a rectangle inside the circle, just slightly smaller that the circle, the area of a S35 sensor, let's say, now draw a rectangle 1/2 the size in side that box, that represents the area of the BMCC sensor (not actual size, but approx. proportion to difference between Super 35 and the Cinema camera.).
Now you can see the image of let's say a 25mm lens, the circle, and the difference in what the sensor is recording off that image between the large box and the smaller one. The scene inside the circle is the same, what changes is how much of that scene is "seen" by the two different size sensors. The circle, a 25mm lens focal length, does not change, but how much of the scene that is recorded, the Angle of View, changes between the two boxes, does change. Hope this helps.
Denny Smith
SHA Productions