The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-300 F3.5-6.3 DC OS HSM and the Tamron AF 70-300mm f4-5.6 LD 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 70-300mm f4-5.6 LD is the longer of the two lenses at 117mm. The Sigma 18-300 F3.5-6.3 DC OS HSM with a length of 102mm, is 15mm shorter. On the other hand, the Sigma 18-300 F3.5-6.3 DC OS HSM has a larger diameter of 79mm compared to the Tamron AF 70-300mm f4-5.6 LD's 77mm 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 70-300mm f4-5.6 LD weighs 435g, 25% (150g) lighter than the Sigma 18-300 F3.5-6.3 DC OS HSM's weight of 585g.
Filter Threads
The Sigma 18-300 F3.5-6.3 DC OS HSM has a filter size of 72mm whereas the Tamron AF 70-300mm f4-5.6 LD 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 72mm filters that we recommend you to consider for the Sigma 18-300 F3.5-6.3 DC OS HSM:
And these are the 62mm filters that we recommend for the Tamron AF 70-300mm f4-5.6 LD:
Lens Mounts
Both the Sigma 18-300 F3.5-6.3 DC OS HSM and the Tamron AF 70-300mm f4-5.6 LD 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 18-300 F3.5-6.3 DC OS HSM is also available in the Canon EF , Nikon F (DX), Pentax KAF3 and Sigma SA mounts.
Tamron AF 70-300mm f4-5.6 LD is also available in Canon EF , Nikon F (FX) and Pentax KAF mounts.
Focal Range
Sigma 18-300 F3.5-6.3 DC OS HSM has a focal range of 18-300mm and
16.7X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-450mm when used on a APS-C / DX format camera.
On the other hand, the Tamron AF 70-300mm f4-5.6 LD has a focal range of 70-300mm and 4.3X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 105 - 450mm.
