Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 10, NO. 1 / JANUARY 1984 / PAGE 103

Multi-function back for Minolta X-700 camera. (evaluation) Stephen B. Gray.

Multi-Function Back for Minolta X-700 Camera

Minolta's top of the line single-lens reflex camera is the X-700, a "state-of-the-art quartz-control electronic 35mm SLR,' as the product guide calls it. It is one of the new breed of 35mm cameras that are almost idiot-proof; you load it, set the film speed, then simply focus and shoot.

The X-700 offers Programmed Automatic Exposure, which "requires absolutely no manual setting of aperture or shutter speed . . . The X-700 program mode automatically selects aperture and shutter speed for proper exposure, maintaining the fastest practicable speed as light dims, giving visible indication and audible beeps, if desired, to guard against blur from subject/camera movement.' The X-700 is said to be the first shutter-weighted system: it is programmed to favor faster speeds in low light.

For those who wish to exercise some control, the X-700 has two other modes. In Aperture-Priority Auto Exposure mode, you select the lens opening, and the camera selects a shutter speed for proper exposure, allowing you to control the depth of field.

In Metered Manual mode, you set the shutter speed and adjust the aperture until the LED next to that speed (in the viewfinder) lights up.

Automatic features of this type are usually based on integrated circuits. However, one of the accessories for the X-700 is the Multi-Function Back, which Minolta calls "the world's first microcomputer-controlled back to offer three camera-control modes for time-lapse, timed long-exposure, and multi-frame sequence photography, plus six data-imprint modes for indentifying or classifying photographs.'

Other X-700 accessories include a motor drive, wireless controller, two flash units, and a Power Grip power source (which has a handle and mounts a flash unit on a swivel for "bouncing' the light).

Multi-Function Back

The Multi-Function Back (Figure 1), easily installed in place of the standard back, protrudes only about a quarter of an inch more than the original back. Yet it performs a variety of functions that weren't available before or required much more hardware than could be attached directly to the camera.

The back consists of a six-character liquid crystal display, a control panel with half a dozen keys, control panel cover, and battery chamber, plus a microprocessor, quartz clock, and an automatic calendar that keeps track of dates up to the year 2099. Once set, the date automatically changes, with leap years and varying number of days in a month all taken care of.

Block Diagram

The unofficial block diagram (Figure 2) was drawn during a discussion with a Minolta manager. It is quite simple: the control panel operates the microprocessor, which controls the camera and the display and also sends signals to the Power Grip when flash is required in interval mode.

Camera Control Modes

Press the FII key on the back, then the MODE key, and you are ready to set one of the three camera-control modes. These modes can be used alone or in combination to control the shutter of the X-700.

You can set the camera to take a picture every three seconds, or every two hours, or every 33 hours, for example. You can set the X-700 to take one picture at each of those times, or several dozen. You can also control how long the shutter stays open.

Using all three modes together, you could set the X-700 to take three frames every four hours, with the shutter open two seconds for each shot. It does all this automatically, without your having to be there.

Interval Mode

The time set in Interval mode determines how long the camera waits between exposures. This mode usually requires using a motor drive or the slower auto winder, although the film can be advanced by hand if the interval is long enough.

Put the X-700 on a tripod, and in Interval mode you can photograph a scene such as traffic patterns, cloud movement or a flower coming into bloom automatically every few minutes, from dawn to dusk. (Figure 3.)

Interval can also be used with flash. The flash turns on, warms up, fires at the precise moment, and shuts off, and the film automatically winds to the next frame. This can be used to photograph plants and animals at night, for example.

The interval can be set for any time between one second and 99 hours, 59 minutes, 59 seconds, the limit of the LCD display.

The interval is set on the LCD display much as you would a digital watch.

Frames Mode

The number set when the Multi-Function Back is in Frames mode determines how many photographs are taken at the interval you set. The number of frames you can set is theoretically the limit of the display--999,999.

Long Exposure Mode

The Long Exposure mode controls how long the shutter stays open to take the photograph. The range is from one second to a maximum of three or six hours, depending on the type of batteries used, and how fresh they are. This mode is used mostly for night scenes or astrophotography.

Put the X-700 on a tripod, aim it at the North Star, set the exposure to several hours, and you can get a spectacular photo showing dozens of concentric rings, as the sphere of stars seemingly circles around the earth's axis. (Figure 4.)

Data-Imprinting Modes

Less interesting photographically than camera-control functions, but just as valuable to those who need them, are the data-imprinting modes. In these six modes, numbers are imprinted in the lower right corner of the film for identifying or classifying the photographs.

The LCD display on the back of the Multi-Function Back is duplicated by a small group of light emitting diodes (LEDs) on the inner side. The LEDs also form six figures in three pairs, but they are only about 3.5 mm high.

These LEDs are mounted in the film pressure plate, and are thus pressed against the film. When turned on in different combinations, they imprint data directly onto the film.

You can imprint the time or date of exposure. You can imprint one number or consecutive numbers, starting at zero or anywhere else.

Imprinting and camera-control functions can be used simultaneously.


Recording the time a photograph is taken can be important in legal and scientific work, and in sports. Thus, you can pinpoint the precise moment a volcano erupts, a space rocket lifts off, or a runner crosses the finish line.

First you set the quartz clock in the Multi-Function Back, which operates in 24-hour time, as in 19 33 42. With the DATA IMPRINT switch set to AUTO, the film will record the time of each shot. When the switch is set to MAN, you can push the blank button at the lower right of the control panel to imprint the time data at any time before, during, or after exposure. If you don't want to imprint the time on a particular frame, just set the switch to OFF.


In Date mode, you have three choices for recording the information. You can set the display and data-imprinter to record the data as year, month, and day (83 12 25). Or month, day, year (12 25 83). Or day, month, year (25 12 83).

Date mode keeps track of special occasions, such as recording a child's growth, or important events such as birthdays, vacations, weddings, graduations, and so on.

Number and Count

In Number mode you can imprint any desired number from 00 00 00 to 99 99 99 on every frame. Or in Count mode you can number the frames consecutively, starting with 00 00 01 or anywhere else.

Using Number mode, you can encode photos with any number up to 999,999, according to your individual filing system.

Count mode is very useful for numbering in sequence the order of finish in a marathon or an auto race, for example.

Film Setting

Minolta's engineers took a small but important item into account when designing the LED data-imprinter. Some films are more sensitive to LEDs than others; for these films the LEDs should not be lighted as long as for the others. So you press the FI key, then the MODE key until only diamonds appear in the LCD display. Next press the diamond key until the correct number of diamonds appears; several dozen films have been categorized by their sensitivity to LEDs, and their settings (by number of diamonds) are given in the owner's manual. For Kodachrome 25/40, for example, you should light four LCD diamonds.

Added Details

Several nice little extra details help make the Multi-Function Back as userfriendly as possible. An LED above the control panel flashes every time data are imprinted on film, so you will know whether the DATA IMPRINT switch is set to AUTO or not. The LCD panel blinks every two seconds when the batteries are low.


The Minolta X-700 camera is available in New York camera stores for $230 or less and the Multi-Function Back at $179 or less.

Photo: Figure 1. The rear of this Minolta X-700 camera shows two accessories attached: a motor drive and the Multi-Function Back. The control panel cover is open to show the operating keys.

Photo: Figure 2. This unofficial block diagram of the Minolta X-700 Multi-Function Back shows how simple the accessory is, yet it operates in nine different control and imprint modes.

Photo: Figure 3. Photographing the blooming of a flower is simple in interval mode, which operates automatically and unattended.

Photo: Figure 4. Using a long-exposure time of several hours, spectacular effects can be achieved with sky photographs.

Photo: Figure 5. Putting the date on pictures helps keep track of special occasions.

Photo: Figure 6. The Court mode can help a sports photographer record the order of finish in a car race.

Products: Minolta X-7000 (still camera)