The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony DT 11-18mm F4.5-5.6 and the Sony 20mm F2.8 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 11-18mm F4.5-5.6 is the longer of the two lenses at 81mm. The Sony 20mm F2.8 with a length of 54mm, is 27mm shorter. Besides being longer, the Sony DT 11-18mm F4.5-5.6 also has a larger diameter of 83mm compared to the Sony 20mm F2.8's 78mm 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 20mm F2.8 weighs 285g, 20% (75g) lighter than the Sony DT 11-18mm F4.5-5.6's weight of 360g.
The Sony DT 11-18mm F4.5-5.6 has a filter size of 77mm whereas the Sony 20mm F2.8 has a 72mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Sony DT 11-18mm F4.5-5.6:
And these are the 72mm filters that we recommend for the Sony 20mm F2.8:
Both the Sony DT 11-18mm F4.5-5.6 and the Sony 20mm F2.8 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.
Sony DT 11-18mm F4.5-5.6 has a focal range of 11-18mm and 1.6X
zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 16.5-27mm
when used on a APS-C / DX format camera.
On the other hand, the Sony 20mm F2.8 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 30mm.