Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Panasonic 35-100mm F4.0-5.6 is the longer of the two lenses at 50mm. The Panasonic 12-32mm F3.5-5.6 Mega OIS with a length of 24mm is 26mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 56mm.
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 12-32mm F3.5-5.6 Mega OIS weighs 70g, 92% (65g) lighter than the Panasonic 35-100mm F4.0-5.6's weight of 135g.
Both Panasonic 35-100mm F4.0-5.6 and Panasonic 12-32mm F3.5-5.6 Mega OIS 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.
Panasonic 35-100mm F4.0-5.6 has a focal range of 35-100mm and 2.9X zoom ratio which has a 35mm equivalent focal range of 70-200mm when used on a FourThirds format camera. Panasonic 12-32mm F3.5-5.6 Mega OIS has a focal range of 12-32mm and 2.7X zoom ratio which has a 35mm equivalent focal range of 24-64mm when used on a FourThirds format camera.