The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony DT 18-135mm F3.5-5.6 SAM and the Sigma 18-125mm F3.8-5.6 DC HSM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Sigma 18-125mm F3.8-5.6 DC HSM is the longer of the two lenses at 89mm. The Sony DT 18-135mm F3.5-5.6 SAM with a length of 86mm, is 3mm shorter. On the other hand, the Sony DT 18-135mm F3.5-5.6 SAM has a larger diameter of 76mm compared to the Sigma 18-125mm F3.8-5.6 DC HSM's 74mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Sony DT 18-135mm F3.5-5.6 SAM weighs 398g, which means it is 92g (18%) lighter than the Sigma 18-125mm F3.8-5.6 DC HSM which has a weight of 490g.
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
Filter Threads
Both the Sony DT 18-135mm F3.5-5.6 SAM and the Sigma 18-125mm F3.8-5.6 DC HSM have the same Filter thread size of 62mm.
Below are links to the 62mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sony DT 18-135mm F3.5-5.6 SAM and the Sigma 18-125mm F3.8-5.6 DC HSM 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 18-125mm F3.8-5.6 DC HSM is also available in Pentax KAF3 mount.
Focal Range
Sony DT 18-135mm F3.5-5.6 SAM has a focal range of 18-135mm and
7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-202.5mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 18-125mm F3.8-5.6 DC HSM has a focal range of 18-125mm and 6.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-187.5mm when used on a APS-C / DX format camera.
