The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-300 F3.5-6.3 DC OS HSM and the Sony DT 18-250mm F3.5-6.3 for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 18-300 F3.5-6.3 DC OS HSM is the longer of the two lenses at 102mm. The Sony DT 18-250mm F3.5-6.3 with a length of 86mm is 16mm shorter. Besides being longer, the Sigma 18-300 F3.5-6.3 DC OS HSM also has a larger diameter of 79mm compared to Sony DT 18-250mm F3.5-6.3's 75mm 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 DT 18-250mm F3.5-6.3 weighs 440g, 24% (145g) lighter than the Sigma 18-300 F3.5-6.3 DC OS HSM's weight of 585g.
Below you can find the dimension and weight table of the 'SuperZoom Lenses in Sony Alpha Mount for size comparison purposes.
SuperZoom Lenses in Sony Alpha Mount for Size Comparison
Lens Mounts
Both Sigma 18-300 F3.5-6.3 DC OS HSM and Sony DT 18-250mm F3.5-6.3 has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Sigma 18-300 F3.5-6.3 DC OS HSM is also available in Canon EF , Nikon F (DX), Pentax KAF3 and Sigma SA mounts.
Focal Range
Sigma 18-300 F3.5-6.3 DC OS HSM has a focal range of 18-300mm and 16.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-450mm when used on a APS-C / DX format camera. Sony DT 18-250mm F3.5-6.3 has a focal range of 18-250mm and 13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-375mm when used on a APS-C / DX format camera.