Another line of compact SLR cameras

The Nikon FM, released as a highlight product of the Ai revolution in 1977, was a manual exposure meter-linked camera, but the camera market at the time was rapidly moving towards TTL-AE in SLR cameras. Naturally, people were looking forward to the appearance of a compact TTL-AE camera like the FM. In response to these expectations, the Nikon FE was released in 1978. At first glance, the FE appears to simply be a Nikon FM with automatic exposure built in, but in reality, there are quite a few differences in concept.

Photometric circuit using SPD and its challenging implementation

The Nikon FE’s metering and shutter control ICs are the same as those in the Nikon EL2. Or rather, it would be more accurate to say that the ICs developed for the FE were used first for the EL2. However, the difference is the power supply voltage, with the FE running on two SR44 silver batteries at 3 volts. Since there is no need to use the large 4SR44, there is no need to use the tricky sublingual tablet format like the EL2, which also contributes to the miniaturization.

The IC package is a flat package, or “crab,” and, like the EL2, it is mounted on a flexible printed circuit board (FPC) attached to the roof of the pentaprism. The FPC is used in the same way as the EL2, but with the FE we have become adept at using it and have made considerable progress in circuit mounting. What’s more, we did something challenging with this camera. When I was meeting with a production engineer I know during development, he said, “Let’s eliminate the leads from all electronic components.” As a designer, I agreed with this and carried out the mounting design in that direction.

Specifically, they used chip-type resistors and capacitors and mounted them on FPCs using reflow soldering, anticipating a method that would later be called “surface mounting.” Reflow soldering involves screen-printing a paste-like solder onto the conductor surface of an FPC, placing chip components on it and passing it through a belt furnace. The solder melts and the components are fixed in place. The production engineer in question immediately purchased a belt furnace for testing, conducted repeated experiments, collected data, and applied it to mass production of FE.

The Phantom Boomerang Package

To tell the truth, we are attempting another big adventure in mounting the electronic circuits of the Nikon FE. As I wrote before, the photocurrent of SPDs and GPDs is very small, so if dirt gets between the electrodes, the insulation will decrease and photocurrent will leak. Therefore, we do not want to expose the wiring from the two terminals of the photodetector to the input terminal of the IC to the outside air if possible.

So we thought it might be a good idea to connect the terminals of the light receiving element directly to the IC package without using lead wires or the wiring pattern of the FPC. We asked an IC package manufacturer to prototype a custom package and tried to attach a light receiving element to it. In other words, we attached the light receiving element to an extension of the photometer circuit package. The wiring between the terminals of the light receiving element and the IC chip runs through the multilayer ceramic of the package, so it does not come into direct contact with the outside air.

Nikon FM and other cameras had two light receiving elements on either side of the viewfinder eyepiece, but because it was difficult to mount two directly in the package, we decided to mount one on the eyepiece. The package is designed so that it hangs down to the side from the light receiving part on the eyepiece, bypassing the square eyepiece, and the IC chip is placed in that part. The package is shaped just like a boomerang.

An unexpected issue

However, an unexpected problem arose. With the shift to AI, a direct-reading aperture scale was added to the lens aperture ring, so the FE also had a window under the nameplate to read the aperture scale and guide it into the viewfinder. External light from that window would directly hit the light-receiving element on the eyepiece, causing a metering error. In the end, the boomerang package was abandoned and a change was made to a format with two light-receiving elements on the left and right of the eyepiece, the same as the Nikon FM. Thus, the boomerang package was forgotten, but the idea of ​​an IC package with a direct connection to the light-receiving element was used in later Nikon F3s.

Differences from Nikon FM

The Nikon FE may seem like a model that simply incorporates an electronically controlled shutter into the body of the Nikon FM to make it an AE camera, but there are quite a few differences in the details. In fact, the two models were designed by different leaders of the design groups, and the differences in their philosophies are evident everywhere.

Pentaprism

The first thing you can notice from the outside is the shape of the pentaprism. The triangular part on the front of the FM is small and sharp-angled, while the FE has a larger surface area and a softer feel. This was also done with the intention of moving the nameplate part, which protrudes forward for the direct-reading aperture display, back slightly towards the viewer. As a result, the scale on the aperture ring is viewed at a shallower angle, and the reading optical system has also been changed.

Viewfinder screen can be changed with the FE

Starting with the FE, it became possible to replace the viewfinder screen. Since the pentaprism section could not be removed like on the single-digit F cameras, it was replaced from the lens mount side with the lens removed. This method itself has been around since around 1960, so it is not new, but as viewfinder screens became more diverse, such as split micro matte and full matte, other companies’ SLR cameras also began to adopt it, so this was a response to that.

The AE-related functions are a continuation of the Nikkormat EL. An ammeter is used for the exposure display in the viewfinder. The needle-type exposure meter is linked during manual shooting, a tradition of the EL series. Since the Nikkormat FT, the power switch has been a lever switch that is turned on and off when the wind lever is at the ready position, but since cameras with electronically controlled shutters cannot take pictures unless the power is on, the lever switch now also functions as a shutter button lock. The FE also follows this configuration. As mentioned last time, the FM, which had a separate shutter button lock, later adopted the same format . The multiple exposure lever is now on the same axis as the wind lever shaft, and this was also made common by a design change on the FM.

Comparison photos