Variable focus assemblies and apparatuses having crossed bearing balls

An optical assembly, comprising:

• a module base;
• an lens barrel assembly configured to move within the module base, the lens barrel assembly having two front tubular slots and two rear tubular slots;
• only two front bearing balls, each housed in a respective one of the two front tubular slots and configured to movably support the lens barrel assembly within the module base at a first side of the lens barrel assembly;
• and
• only two rear bearing balls, each housed in a respective one of the two rear tubular slots and configured to movably support the lens barrel assembly within the module base at a second side of the lens barrel assembly,
• wherein the only two front bearing balls are in a crossed positional arrangement with respect to the only two rear bearing balls such that each corner of the lens barrel assembly receives only one bearing ball when viewed along an optical axis of the optical assembly.