The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon EF 85mm F1.4L IS USM and the Sigma 800mm F5.6 EX DG 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. Sigma 800mm F5.6 EX DG HSM is the longer of the two lenses at 521mm. The Canon EF 85mm F1.4L IS USM with a length of 105mm, is 416mm shorter. Besides being longer, the Sigma 800mm F5.6 EX DG HSM also has a larger diameter of 157mm compared to the Canon EF 85mm F1.4L IS USM's 87mm 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. Canon EF 85mm F1.4L IS USM weighs 950g, which means it is 3950g (80%) lighter than the Sigma 800mm F5.6 EX DG HSM which has a weight of 4900g.
Filter Threads
The Canon EF 85mm F1.4L IS USM has a filter size of 77mm whereas the Sigma 800mm F5.6 EX DG HSM has a 46mm 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 Canon EF 85mm F1.4L IS USM:
And these are the 46mm filters that we recommend for the Sigma 800mm F5.6 EX DG HSM:
Lens Mounts
Both the Canon EF 85mm F1.4L IS USM and the Sigma 800mm F5.6 EX DG HSM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Sigma 800mm F5.6 EX DG HSM is also available in Nikon F (FX) and Sigma SA mounts.
Focal Range
Canon EF 85mm F1.4L IS USM is a prime lens with fixed focal lenght of 85mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
136mm.
On the other hand, the Sigma 800mm F5.6 EX DG HSM is a prime lens with fixed focal lenght of 800mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 1280mm.