Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sony FE 70-300mm F4.5-5.6 is the longer of the two lenses at 144mm. The Sony E 70-350mm F4.5-6.3 G OSS with a length of 142mm is 2mm shorter. Besides being longer, the Sony FE 70-300mm F4.5-5.6 also has a larger diameter of 84mm compared to Sony E 70-350mm F4.5-6.3 G OSS's 77mm 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. Sony E 70-350mm F4.5-6.3 G OSS weighs 625g, which means it is 229g (26%) lighter than the Sony FE 70-300mm F4.5-5.6 which has a weight of 854g.
Below you can find the dimension and weight table of the 'Telephoto Zoom Lenses in Sony E Mount for size comparison purposes.
Telephoto Zoom Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both Sony E 70-350mm F4.5-6.3 G OSS and Sony FE 70-300mm F4.5-5.6 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony ZV-E10, Sony A6600 and Sony A6100.
Focal Range
Sony E 70-350mm F4.5-6.3 G OSS has a focal range of 70-350mm and 5.0X zoom ratio which has a 35mm equivalent focal range of 105-525mm when used on a APS-C / DX format camera. Sony FE 70-300mm F4.5-5.6 has a focal range of 70-300mm and 4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 105 - 450mm.