The meter attaches to the lens mount to provide through-the-lens metering. The cell is lowered into position, and raised when not in use, by handles on the side of the meter. In the lowered position one of the handles obscures the shutter release and prevents accidental exposure. The current produced by the cell is measured on a separate micro-ammeter (with a range of 5 - 30 microamperes and 1000 - 5000 ohm internal resistance). The exposure meter has to be calibrated by making trial exposures, thereafter a particular deflection on the ammeter can be equated to the correct exposure setting on the camera. The meter itself provides an extension of 20 mm and has standard Exakta bayonets on each side.

The calculator is first set to the size of the object, windows for each lens then show the extra extension required, the exposure value increase in EV and the lens-to subject distance. Another window shows the magnification and the depth-of-field at f11. On the other side of the calculator, windows for each lens show which accessory will be suitable (Proxar, tubes, bellows). There is a separate scale to convert EV values to shutter speed and aperture combinations. The scales are for lenses of 80, 100, 110, 120, 135, 150 and 250 mm focal length.