1. Mirror Shutter
The light from the taking lens is reflected up by a spinning half moon shaped mirror. Since this mirror rotates, half the time the light is projected onto the film, the other half up into the viewfinder. While the light is reflected up, the mirror covers the film, which is transported to the next frame. Since this mirror's function is both reflecting and shuttering light, it is known as a "mirror shutter".

2. Fiber Optic Screen
The light is projected onto a screen (a fiber optic screen, in case of the 416), which acts as a rear projection screen.

3. Field Lens
The field lens (named as such because located close to the image field) refracts the light into the entrance pupil of the primary viewfinder lens and the video assist lens.

4. Video Assist Beam Splitter
80% of the light passes straight up, while 20% is reflected to the side and projected through the video assist optics (not pictured) onto the video assist CCD sensor.

5. Supplementary Lens

6. Protective Glass
An optically clear glass plate on the top surface of the camera body protects the components underneath from dirt contamination.

7. Supplementary Lens

8. Partial Mirror
The light from the fiber optic screen is reflected into the viewfinder. At the same time, the light from the ARRIGLOW LEDs above is let through. This light is then reflected off the frame line markings on the fiber optic screen, providing illuminated frame lines when needed.

9. 90 Degree Prism

10. Primary Lens
Picks up the image
from the fiber optic
screen.

11. Mirror

12. Pechan Prism
Automatically keeps the image upright when the viewfinder is rotated.
Also allows for manual image rotation.

13. Secondary Lens
Provides the image for the eyepiece.

14. Mirror

15. Protective Glass
Located at the mechanical interface to the eyepiece or eyepiece extension, the protective glass prevents dust from getting into the viewfinder optics.

16. Eyepiece
The eyepiece allows the operator to view the image. It also provides a focus adjustment of approximately +/- 3 diopters.