Should I get the Canon RF 70-200mm F2.8 L IS USM Lens or the Sony FE 70-200mm F2.8 GM OSS II Lens?

As I maintain a mixed kit of Sony and Canon gear, I was anxious to see how the Sony FE 70-200mm F2.8 GM OSS II Lens compared to the equivalent Canon lens, the RF 70-200mm F2.8 L IS USM Lens.

In the image quality comparison, the two lenses appear near equals. The Canon lens seems slightly sharper in the center of the frame from 70mm through 135mm, but any sharpness difference is not meaningful as a differentiator. At 200mm, the Sony lens has about one stop less peripheral shading to its advantage. The Canon lens has slight pincushion distortion at 70mm vs. a tiny amount of pincushion distortion. Both lenses trend toward pincushion distortion as their focal lengths are increased, with the Canon lens having less distortion than the Sony lens by 100mm and through 200mm. The Sony lens shows more color blur in the mid focal length range and blurs corner stars slightly more. The Canon lens produces slightly better specular highlight bokeh and slightly better points on sunstars.

The Sony lens mounted on an Alpha 1 in either AF-S or AF-C mode does not focus slowly, but the Canon lens with an EOS R5 behind it focuses noticeably faster in side-by-side testing. Neither lens makes much noise when focusing, but the Sony lens is slightly quieter.

The Sony lens is compatible with teleconverters, adding the versatility of up to the 140-400mm range with the 2x mounted. However, the teleconverter magnification is not without impact to the image quality, especially with the 2x in the optical path.

Most will find the smaller retracted size vs. fixed size the biggest differentiator between these lenses.

The Sony FE 70-200mm F2.8 GM OSS II Lens vs. Canon RF 70-200mm F2.8 L IS USM Lens comparison shows, as seen in the comparison image above, the Canon lens measuring considerably smaller — when retracted. The compact Canon lens size is easier to stow a camera backpack and similar cases. Zoomed to 200mm, the Canon measures 0.27" (7mm) longer. Lenses maintaining a fixed size favor in-the-hand use, giving the Sony lens a different advantage.

When zoomed, the elements inside the lens move and repositioning elements can change the balance of the lens — regardless of the external size changing. However, the large objective lens elements remaining in position are advantageous in this regard, and the Sony lens maintains slightly better balance throughout the zoom range.

The Canon lens is slightly wider.

The Sony FE 70-200mm F2.8 GM OSS II Lens was introduced as the "World's Lightest Large-aperture Telephoto Zoom Lens", qualified to full-frame F2.8 70-200mm telephoto zoom lenses that support autofocus. The Sony lens is indeed lighter than the Canon lens, but the measured in-use (with tripod foot and hood) difference is only 2.9 oz (53.2g). Of that difference, 1.6 oz (13.3g) is in the hood weights. Few will find significance in the weight difference between these lenses.

The Sony lens features a front-positioned focus ring. Positioning the zoom ring toward the back of the lens provides a better balance for handheld zooming. Impacting the Sony lens's advantage is the aperture ring positioned behind the zoom ring. The aperture ring is a Sony lens feature advantage, but only for those intending to use it. Making space for the aperture ring shifts the zoom ring forward modestly, farther forward than the Canon lens's zoom ring.

The front element positioned farther forward of the mount gives the Sony lens a modestly better handheld balance at the wider focal lengths. The balance difference equalizes by the longer focal lengths.

Switches add control, but they also add complication, and the aperture ring adds two switches to the design. The zoom lock switch adds one to the Canon side of the equation, and the Sony DMF switch takes the count back to a two-switch lead. It is easier to tactilely find the Canon lens's switches, and the Canon lens's switches are less recessed and easier to use.

The Sony tripod hood is fully integrated and considerably smoother. However, the Canon lens's entire tripod collar can be removed (erasing the weight difference). The Sony lens collar's 90° marks are easier to align, and its tripod foot is removable (and replaceable with an integrated dovetail mount).

Consuming space utilized by the Sony lens's tripod collar is the Canon lens's control ring. Note that this ring can control the aperture.

The Sony lens has three focus hold buttons, and its hood window is tighter.

The additional fixed lens barrel length provides room for the Sony lens to have a longer focus ring.

At review time, the Sony lens costs $1.00 less than the Canon lens.

The bottom line is that both lenses are outstanding. Photographers deciding their camera brand choice at lens selection time will need to look carefully at the differentiating features between these lenses, along with those of the other lens models destined for their kit. In the end, most photographers with a Sony kit will choose the Sony FE 70-200mm F2.8 GM OSS II Lens, and most photographers with a Canon kit will purchase the Canon RF 70-200mm F2.8 L IS USM Lens.