The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-250mm f3.5-6.3 II LD and the Sigma 10-20mm F4-5.6 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. Tamron AF 18-250mm f3.5-6.3 II LD is the longer of the two lenses at 84mm. The Sigma 10-20mm F4-5.6 EX DC HSM with a length of 81mm, is 3mm shorter. On the other hand, the Sigma 10-20mm F4-5.6 EX DC HSM has a larger diameter of 84mm compared to the Tamron AF 18-250mm f3.5-6.3 II LD'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. Tamron AF 18-250mm f3.5-6.3 II LD weighs 430g, which means it is 40g (8%) lighter than the Sigma 10-20mm F4-5.6 EX DC HSM which has a weight of 470g.
Filter Threads
The Tamron AF 18-250mm f3.5-6.3 II LD has a filter size of 62mm whereas the Sigma 10-20mm F4-5.6 EX DC HSM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the Tamron AF 18-250mm f3.5-6.3 II LD:
And these are the 77mm filters that we recommend for the Sigma 10-20mm F4-5.6 EX DC HSM:
Lens Mounts
The Tamron AF 18-250mm f3.5-6.3 II LD has the Canon EF lens mount whereas the Sigma 10-20mm F4-5.6 EX DC HSM has the Pentax KAF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount.
Tamron AF 18-250mm f3.5-6.3 II LD is also available in the Nikon F (DX) , Sony Alpha and Pentax KAF mounts.
Sigma 10-20mm F4-5.6 EX DC HSM is also available in Canon EF , Four Thirds, Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Focal Range
Tamron AF 18-250mm f3.5-6.3 II LD has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-400mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 10-20mm F4-5.6 EX DC HSM has a focal range of 10-20mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-30mm when used on a APS-C / DX format camera.
