The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 18-135mm F3.5-5.6 IS and the Sigma 30mm F1.4 EX 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. Canon 18-135mm F3.5-5.6 IS is the longer of the two lenses at 96mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 37mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 77mm.
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. Sigma 30mm F1.4 EX DC HSM weighs 430g, 16% (85g) lighter than the Canon 18-135mm F3.5-5.6 IS's weight of 515g.
Filter Threads
The Canon 18-135mm F3.5-5.6 IS has a filter size of 67mm whereas the Sigma 30mm F1.4 EX DC HSM has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Canon 18-135mm F3.5-5.6 IS:
And these are the 62mm filters that we recommend for the Sigma 30mm F1.4 EX DC HSM:
Lens Mounts
Both the Canon 18-135mm F3.5-5.6 IS and the Sigma 30mm F1.4 EX DC HSM has the same Canon EF-S lens mount. Some of the latest released cameras that are compatible with the Canon EF-S lenses are Canon T8i, Canon 90D and Canon SL3.
Canon 18-135mm F3.5-5.6 IS is also available in the Canon EF-S mount.
Sigma 30mm F1.4 EX DC HSM is also available in Nikon F (DX) , Four Thirds, Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Canon 18-135mm F3.5-5.6 IS has a focal range of 18-135mm and
7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-216mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 30mm F1.4 EX DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of 48mm when used on a APS-C / DX format camera.
