The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony DT 18-70mm F3.5-5.6 and the Sony DT 18-55mm F3.5-5.6 SAM 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. Sony DT 18-70mm F3.5-5.6 is the longer of the two lenses at 77mm. The Sony DT 18-55mm F3.5-5.6 SAM with a length of 69mm, is 8mm shorter. On the other hand, the Sony DT 18-55mm F3.5-5.6 SAM has a larger diameter of 70mm compared to the Sony DT 18-70mm F3.5-5.6's 66mm 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 18-55mm F3.5-5.6 SAM weighs 210g, 10% (25g) lighter than the Sony DT 18-70mm F3.5-5.6's weight of 235g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Sony Alpha Mount for size comparison purposes.
Standard Lenses in Sony Alpha Mount for Size Comparison
Filter Threads
Both the Sony DT 18-70mm F3.5-5.6 and the Sony DT 18-55mm F3.5-5.6 SAM have the same Filter thread size of 55mm.
Below are links to the 55mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sony DT 18-70mm F3.5-5.6 and the Sony DT 18-55mm F3.5-5.6 SAM 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.
Focal Range
Sony DT 18-70mm F3.5-5.6 has a focal range of 18-70mm and
3.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-105mm when used on a APS-C / DX format camera.
On the other hand, the Sony DT 18-55mm F3.5-5.6 SAM has a focal range of 18-55mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-82.5mm when used on a APS-C / DX format camera.