A new patent, discovered by Northlight Images, reveals that the Canon RF 300mm f/2.8L IS USM will have a total length of 274.19mm. Intriguingly, the existing DSLR version, the Canon EF 300mm f/2.8L IS USM II is actually a little shorter at 248mm. That means the new RF variety could be around 10% longer.

The Canon EF 300mm f/2.8L IS II USM lens performs stunningly in every respect. The ring-type USM autofocus is blazingly fast and accurate, while the 4-stop image stabiliser makes for consistently
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canon ef 300mm f 2.8 l is ii usm review