Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Panasonic 14-140mm F3.5-5.6 II OIS is the longer of the two lenses at 75mm. The Panasonic 12-60mm F3.5-5.6 with a length of 71mm is 4mm shorter. Besides being longer, the Panasonic 14-140mm F3.5-5.6 II OIS also has a larger diameter of 67mm compared to Panasonic 12-60mm F3.5-5.6's 66mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Panasonic 12-60mm F3.5-5.6 weighs 210g, 26% (55g) lighter than the Panasonic 14-140mm F3.5-5.6 II OIS's weight of 265g.
Lens Mounts
Both Panasonic 14-140mm F3.5-5.6 II OIS and Panasonic 12-60mm F3.5-5.6 has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are Panasonic GH6, OM System OM-1 and Panasonic GH5 II.
Focal Range
Panasonic 14-140mm F3.5-5.6 II OIS has a focal range of 14-140mm and 10.0X zoom ratio which has a 35mm equivalent focal range of 28-280mm when used on a FourThirds format camera. Panasonic 12-60mm F3.5-5.6 has a focal range of 12-60mm and 5.0X zoom ratio which has a 35mm equivalent focal range of 24-120mm when used on a FourThirds format camera.