The purpose of 35mm lens adapters are to achieve 35mm film frame size, which is 24x18. The still camera 35mm frame size is 36x24, which is called "full frame". The Letus35 Extreme is at 46x30. This allows a user to zoom in (to compensate for shifted image sensors etc.) and still get a 36x24 "full frame" image. This is still larger than academy frame size of 24x18 which is the size most look to achieve.

With the 46x30 frame size in the Extreme, there is enough extra frame to achieve an academy frame size of 24x18 or even the full frame size of 36x24 even with a shifted image sensor.