The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Olympus 300mm F4 IS Pro and the Canon 400mm f4.0 DO IS USM 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 400mm f4.0 DO IS USM is the longer of the two lenses at 233mm. The Olympus 300mm F4 IS Pro with a length of 227mm, is 6mm shorter. Besides being longer, the Canon 400mm f4.0 DO IS USM also has a larger diameter of 128mm compared to the Olympus 300mm F4 IS Pro's 93mm 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. Olympus 300mm F4 IS Pro weighs 1270g, which means it is 670g (34%) lighter than the Canon 400mm f4.0 DO IS USM which has a weight of 1940g.
Filter Threads
The Olympus 300mm F4 IS Pro has a filter size of 77mm whereas the Canon 400mm f4.0 DO IS USM has a 52mm 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 Olympus 300mm F4 IS Pro:
And these are the 52mm filters that we recommend for the Canon 400mm f4.0 DO IS USM:
Lens Mounts
The Olympus 300mm F4 IS Pro has the Micro Four Thirds lens mount whereas the Canon 400mm f4.0 DO IS USM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are OM System OM-3 Astro, OM System OM-5 II and OM System OM-3 for the Micro Four Thirds Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Focal Range
Olympus 300mm F4 IS Pro is a prime lens with fixed focal lenght of 300mm which has an effective (full-frame 35mm equivalent) focal range of
600mm when used on a FourThirds format camera.
On the other hand, the Canon 400mm f4.0 DO IS USM is a prime lens with fixed focal lenght of 400mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 640mm.
