The Omega E-3 Enlarger evolved from the large format enlargers produced for the military during World War II.  The E-3 was the first Omega enlarger to feature the new autofocus design, which worked by means of a wheel that followed a "track" as the carriage was raised and lowered.  The wheel was connected to a lever mechanism that altered the focus adjustment.  The tracks were long aluminum plates configured for each focal length of lens being used.  Due to variations in manufacturing tolerances, each track had to be custom profiled for the individual characteristics of a particular lens and lens mount combination.

The lamphouse used in the E-3 was a "cold light" head, using a grid of four straight fluorescent tubes. The tubes of that era were slow to reach maximum brightness, so the lamphouse had to be left on during the entire printing session, requiring an electrically controlled under-the-lens shutter mechanism to control the exposures.  The lamphouse also had a filter drawer for color printing filters, and the lamphouse could be tilted and rotated for distortion control.

The Automega E-4 was essentially the E-3 chassis with a new Omegalite E lamphouse replacing the slow starting cold light head of the E-3, thus eliminating the need for the shutter mechanism.  The shortest focal length lens that could be fitted to either enlarger was 90mm, so that focal length had to be used for all negative formats smaller than 2¼"x3¼".

Used Advice: Some parts, such as lens discs are still current, but parts that are not, such as negative carriers, lens mounts and autofocus tracks, may be difficult to find.