Canon Patent Application: Canon RF 17-35mm
Canon next month is going to be completing the F2.8L Trinity of lenses according to the latest rumor, so what is next? It stands to reason that Canon would then shift their focus onto the F4.0 trinity. But what is after that? Canon has to also focus on more consumer lenses, such as this one a 17-35 4.0-5.6
Canon describes this as;
In recent years, the imaging optical system used in an imaging apparatus has a small size, light weight and easy portability, and in order to correspond to a wider range of imaging conditions, a wide angle of view and high optical power over the entire zoom range It is desired that the zoom lens has performance. As a zoom lens having a small overall size and a wide angle of view, there is known a negative lead type zoom lens in which a lens unit having negative refractive power is disposed closest to the object side.
The patent application contains only two embodiments, both 17-35mm lenses. Interestingly none of these two lenses show any size benefits of going to a mirrorless mount, as both would have a total lens length of around 101 to 102mm. The current Canon EF 17-40, or the 16-35mm has the total lens length of 83 to 89mm. You'll quickly notice that what we suggest is the length of the lens differs from the embodiment "lens total length". That's because in the embodiment they measure the distance to the sensor plane, which includes the 20mm distance between the mount and the sensor.
Even though this patent application doesn't specifically mention stabilization, Canon in the past has used elements such as the first element of grouping L2 for image stabilization.
The two embodiments;
focal length 17.50 27.00 33.95
f-number 4.00 5.03 5.80
half field angle (degree) 51.03 38.71 32.51
image height 21.64 21.64 21.64
lens total length 121.00 118.39 121.18
BF 20.00 30.99 38.92
focal length 17.50 27.00 33.95
f-number 3.94 4.92 5.69
half angle of view (degrees) 51.03 38.71 32.51
Image height 21.64 21.64 21.64
total lens length 122.00 119.11 121.87
BF 20.00 31.62 40.07
Canon Patent Application 2019-074633
Update: My first look at this had it as a fixed aperture F4.0 lens, clearly re-reading it shows that it's a 4-5.6
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