Viewfinders

Discussion of the viewfinders used on the Eclair NPR must first start with a description of the camera's viewing system. The NPR is equipped with reflex viewing. That is, the operator is looking through the actual taking lens and sees the exact same image that is being sent to the film aperture. This is very different from a camera like the B&H Filmo where the operator peers into a finder running parallel to the actual lens. With a camera like this you would see an image approximately similar in size and position to what the film aperture would see but it is not the actual image. As you got closer to the subject the image seen by the lens and the one seen by the finder would move further away from each other due to the element of parallax error. Reflex viewing is obviously preferable because it provides for parallax-free viewing since the operator and the camera see the same thing. It also helps to insure the image being presented to the film is properly focused and framed. Depending on the particular camera, the image from the lens can be split between the film aperture and the viewfinder using a prism or beam splitter or it can be alternated between the two using a mirror type shutter. Using a system that splits or divides the light from the lens is less desirable than one that alternates because of the potential for tremendous light loss to the film aperture.

With the NPR, the shutter is fitted with a high-gain mirror that rotates at a 45 degree angle to the lens (Fig. 1). During the time the shutter is closed and is blocking all light from reaching the film aperture, almost 100% of that light is being reflected by this mirror surface up to the ground glass focusing screen. From here the light is again bent 90 degrees by another mirror and sent across to the port opening for the viewfinder. Because the ground glass is precisely fixed within the camera, itself, it cannot shift in position. Once calibrated by the camera technician in terms of lens flange distance and reticule-to-aperture alignment, it will remain permanent. Removal and reinstallation of the viewfinder will not affect the ground glass in any way. All framing and focusing is now done against this constant. The viewfinder's objective is first focused by the operator so that the grain of the ground glass is clearly defined. The taking lens is then focused to produce a sharp image on the same ground glass. Another feature of the NPR's viewing system is the lack of an aperture mask. Without the introduction of this mask to block off that part of the lens that does not reach the film aperture, the operator is given access to much more of what the lens actually sees. This can be explained in Fig. 2. The lens, being round in nature, actually produces an image that is round. The film aperture, however, is a rectangle that must sit well within this round world. The end result is a certain percentage of image the lens sees that will never reach the film. The operator, being the inquisitive type, will gladly make use of this extra image. For him/her this extra visual information outside the film frame will help in determining where and when to move the camera to get the next best shot.

There were only two viewfinders offered by Eclair for the NPR. The first, which came installed on Eclairs released in 1963, was a viewfinder made by the French optics and lens manufacturer, Kinoptic. The Kinoptic magnified the image by twelve times and was designed to enable either left or right eye viewing by simply swinging the objective arm away from or towards the camera. The objective could be adjusted to the operators eye strength by plus or minus six diopters. A rather large, relatively bright eyepiece was provided. A built-in light trap to close off the eyepiece was included to keep light from travelling back down the viewfinder and fogging the film. Normally in the closed position, it was activated by pressure from the operator's eye against the rubber eyecup. Although this early model was known as a rotating viewfinder, this terminology can be very misleading and needs some explaining. By releasing the locking screw at the front of the optics tube, the finder could, in fact, be rotated 360 degrees around. However, it would only show an image that was erect and level with the taking lens when the eyepiece was parallel to the camera, as is shown in Fig. 3. In fact, there is a detent that snaps the finder into place when you reach this position so there is no mistaking it! In any other position other than this, the image would exhibit some degree of tilt. For example, if the eyepiece was straight up and down, exactly perpendicular to the camera, as in Fig. 4a, the image would be rotated at a 90 degree angle clockwise as in Fig 4b. Pushing the finder more forward would continue the tilt on around until the image was completely upside down. All cameras of this early vintage had similar style finders that did not allow off-axis viewing. Few, if any, even allowed the finder to rotate. They were usually fixed against the side of the camera. This was a condition that early documentary filmmakers simply had to live with...and they did just fine.

It was not until sometime around early 1969 that the French lens manufacturer, Angenieux, introduced a new viewfinder for 16mm cameras like the Eclair, Photosonics and Frezzolini that was truly orientable as well as rotatable (see Fig. 5). Through the use of a porro abbe prism within the design, the Angenieux viewfinder now made it possible for the operator to shoot comfortably at any angle and camera height. With this new finder, the eyepiece could be rotated to any position around a 360 degree axis (see Fig. 6a) and still maintain an image that was erect and level at all points within the arc (see Fig 6b). Unlike the Kinoptic, there were no detents in the rotation at 45 degree intervals. Rather, there was a friction drag adjustment collar which also served to lock off the finder at any position. Like the Kinoptic that proceeded it, there was complete adjustment for left and right eye viewing and a diopter adjustment of plus or minus five diopters. An addition, if the objective was disassembled, a technician could further tune the strength another few diopters either way. The Angenieux used a manually activated light trap consisting of a rotating ring located just behind the back of the eyepiece to close off the optics from extraneous light. It is also important to note the Angenieux viewfinder was also at least 100% brighter than the Kinoptic. That means a gain of at least one full stop in viewing brightness which was a great help to the operator shooting wide open in available light!

While there are claims that other finders can be used on the NPR, the operator should be careful. The orientable viewfinder made by Cinema Products for the CP-16R (see Fig. 7) is optically and mechanically compatible with the NPR however the prism arm is mounted on the front of the optics tube (similar to the finder on the Eclair ACL), rather than on the rear like the Angenieux. This means the distance between the eyecup and the operators eye is increased dramatically from where it should be. The result is the need to hyper-extend ones neck forward at least an inch or more to reach the eyepiece. While this finder should work just fine in situations where the camera is on a tripod, using it when shooting off the shoulder may be painful, to say the least.


On a personal level, when I purchased my NPR I was simply not aware there were two different types of viewfinders so I ended up with the Kinoptic. I have since purchased the Angenieux and I'm glad I did. While the Kinoptic was more than satisfactory for off the shoulder shooting, it was very cumbersome to use when shooting an interview. I found I had to get down on my knees to look into the viewfinder. With the Angenieux I can now make just the slightest tweak to the viewfinder to get the perfect position for every shooting situation I find myself in. It has certainly been a very freeing experience for me and it can only help to improve my camera technique. Perhaps I've been spoiled from shooting video for so long although one of my first film cameras was a Bolex DS-8 and I shot interviews on my knees with that, as well.