Cosina E1 Solar

The Cosina E1 Solar is an analog single-lens reflex (SLR) camera for the 35mm format, distinguished by a special feature: its power is supplied exclusively by an integrated solar cell.

The model was introduced in the mid-1990s and produced in Japan. In Germany, the model was sold by Foto Quelle as the Revue Solar 100. Another variant was the Ricoh XR Solar.

Lenses for the Camera

The Cosina E1 Solar uses the “K” bayonet mount, which means it is compatible with a wide variety of lenses that feature this common connection.

Focusing is done manually using the focusing ring on the lens. A central split-image indicator surrounded by a microprism ring in the viewfinder serves as a focusing aid. Alternatively, focus can be achieved across the entire focusing screen. Focus is considered correct when the split image is aligned in the split-image indicator, or the flickering in the microprism ring disappears, or the image on the focusing screen reaches maximum sharpness.

Exposure Settings

The camera features a TTL exposure metering system at full aperture with center-weighted integral metering. The metering range at ISO 100 extends from EV 5 (e.g., equivalent to f/2 at 1/8 second) to EV 17 (equivalent to f/16 at 1/2000 second).

Exposure is set manually, with the system assisting the photographer. There are three LEDs in the viewfinder: a “+” for overexposure, a “0” for correct exposure, and a “-” for underexposure.

To set the correct exposure, press the shutter button halfway to activate the metering. Then, adjust the aperture on the lens ring or the shutter speed on the shutter speed dial until the central “O” LED lights up (zero-adjustment method).

The camera features a mechanical metal focal plane shutter that travels vertically and allows exposure times from 1 second to 1/2000 second, as well as a “B” (bulb) setting for long exposures.

Exposure times are selected using the shutter speed dial on the top of the camera. Only the detent values ​​may be set, no intermediate values.

The aperture is set using the aperture ring directly on the lens. You can either preselect a shutter speed and adjust the aperture (shutter priority) or preselect an aperture and adjust the shutter speed (aperture priority) to achieve the correct exposure according to the display.

Flash System

The Cosina E1 Solar is equipped with a standard hot shoe with a center contact (X-contact). This allows for the direct connection of external flash units without an additional sync cable.

Flash synchronization occurs at a shutter speed of 1/125 second or slower. Faster shutter speeds result in partial shadowing of the image by the shutter curtain.

Exposure during flash photography is controlled manually. The photographer must set the appropriate aperture on the lens according to the flash unit’s guide number (G.N.), the set film speed, and the distance to the subject.

Additional Features

In addition to its basic functions, the E1 Solar offers several useful additional features.

A mechanical self-timer is integrated, which is activated via a lever on the front of the camera. After pressing the shutter button, the self-timer runs for approximately 10 seconds before the picture is taken. Once activated, the self-timer cannot be stopped.

A standard tripod thread is provided on the bottom of the camera for tripod shots.

A special feature is the multi-exposure lever. If this is operated while the film advance lever is being cocked, the shutter is recocked but the film is not advanced. This allows multiple subjects to be exposed in the same frame without the frame counter counting down.

The camera also features a depth-of-field preview button, which allows you to check the depth of field at the currently set aperture in the viewfinder before taking the picture.

An additive frame counter displays the number of pictures taken and automatically resets to “S” (Start) when the back is opened. A small window next to the rewind knob serves as a film advance indicator; if the rewind knob turns during film advance, the film advances correctly.

Dimensions and Weight

The dimensions of the Cosina E1 Solar are 138.5 mm (width) x 91.0 mm (height) x 66.2 mm (depth). The camera body alone weighs 380 grams, making it a relatively compact and lightweight representative of the SLR cameras of its era.

Power Supply

The power supply of the Cosina E1 Solar is its most outstanding feature. It requires no conventional batteries. Instead, it is equipped with a solar cell and a capacitor.

The light falling on the solar cell is converted into electrical energy. This energy is either used directly to operate the exposure meter or stored in the capacitor for later use.

If the camera has been stored in the dark for an extended period, the capacitor must first be charged. To do this, the solar cell should be exposed to bright light (at least 4,000 lux, comparable to a 20W fluorescent lamp at a distance of 20 cm) for a few minutes.

After this charge, the manufacturer states that the camera is ready for use for at least 10 minutes, even without further light exposure. A special solar lever next to the film speed dial offers two settings: The green mark is intended for normal operation, which utilizes stored energy. The red mark should be selected when the camera is used directly from the dark in moderate light (from approximately 400 lux, comparable to a room lit at night) to potentially optimize the direct light output.

In general, it is recommended not to store the camera permanently in the dark to keep the capacitor charged. Without sufficient charge or sufficient ambient light, the exposure display in the viewfinder will not function (except in the “B” setting).

Film Recommendations for the Cosina E1 Solar

The Cosina E1 Solar uses standard 35mm film (24x36mm format).

The film speed must be set manually using the film speed dial. The adjustable range is from ISO 25/15° to ISO 1600/33° in 1/3-stop increments. Automatic DX code detection is not available.

The choice of film depends on the subject and lighting conditions. For shots in bright daylight, such as landscapes or on the beach, films with lower speeds (e.g., ISO 100 or 200) are suitable, as they often have finer grain. For indoor shots, sports photography, or low-light situations, higher-sensitivity films (e.g., ISO 400, 800, or higher) are more suitable, as they allow for shorter exposure times or smaller apertures to avoid motion blur or camera shake.

Candid films for the Cosina E1 Solar include Fujifilm Superia 400* for color shots and Kodak T-Max 400* for black-and-white photos.

Quick Operation Guide

1. Check Charge/Charge: Expose the camera to bright light if necessary. Set the solar lever to the green mark.
2. Load Film: Pull up the rewind knob to open the back. Insert the film cassette into the compartment. Insert the film tab into the slot on the take-up spool and ensure that the perforations engage with the teeth of the advance wheel.
3. Close Camera: Close the back until it clicks.
4. Advance Film: Operate the film advance lever and press the shutter button. Repeat this process until the frame counter reaches “1”. Check that the rewind knob turns.
5. Set film speed: Set the film’s ISO value using the control dial.
6. Set exposure: Select the desired aperture on the lens or exposure time on the shutter speed dial.
7. Meter and focus: Look through the viewfinder. Press the shutter button halfway to activate the light meter. Focus with the focus ring (split image/microprism).
8. Adjust exposure: Adjust the aperture or exposure time until the “O” LED in the viewfinder lights up.
9. Release the shutter: Press the shutter button all the way down.
10. Advance film: Pull the film advance lever all the way down.
11. Rewind film: After the last shot, press the rewind button on the bottom of the camera. Extend the rewind crank and turn it clockwise until the film is completely rewound into the cassette (resistance should decrease). Open the back cover and remove the film.