While potentially a little sparse when it was first launched, the Canon RF mount is steadily being populated with lenses. However, there are still some gaps in the RF-mount Canon lens line-up that could definitely do with being filled. One of these gaps is the f/4 trinity – a collection of an ultra wide zoom (such as a 15-35mm f/4), a 24-70mm f/4 and a 70-200mm f/4.
This is similar to the f/2.8 trinity (which features identical focal lengths but with a constant aperture of f/2.8 instead of f/4), but usually comes with the benefit of being smaller, lighter and cheaper.
• Read more: Best Canon RF lenses
Luckily, Canon News has uncovered a recent patent application that shows that one of these lenses seems to be on the way. Apparently, Canon has put forward an application for a Canon RF 24-70mm f/4 L lens. Canon News explains that the patent application details multiple different optical designs, but that they're all fairly similar: "Given the backfocus distance and the image height, these designs are most certainly for the RF mount".
You can see the information detailed in the application below:
• Focal length: 24.73mm 40.97mm 67.90mm
• F Number: 4.12 4.12 4.12
• Half angle of view: 41.19° 27.84° 17.67°
• Image height: 21.64mm 21.64mm 21.64mm
• Total lens length: 145.52mm 135.76mm 160.05mm
• BF: 18.00mm 25.64mm 55.54mm
Interestingly, the Canon RF 24-70mm f/4 L isn't the only one of the f/4 trilogy that Canon are working on. A previous rumor from Canon Rumors advised that a Canon RF 70-200mm f/4L IS USM had appeared for Russian certification, which means we could be seeing an official announcement for this lens soon.
In the meantime, we'll likely have to wait a little longer for the arrival of the Canon RF 24-70mm f/4 L if Canon are only just applying for a patent now. However, it's definitely reassuring to see their continued focus on filling out the Canon RF lens line-up.