We expect to see an RF 70-200mm f/2.8L IS USM announced some time in 2019 as part of the “holy trinity” of f/2.8 zoom lenses for Canon's EOS R system.
Here's the first patent for such an optical formula uncovered by Canon News.
US Patent Application 20190004296
- Focal length: 72.00 135.00 194.99
- F-number: 2.92 2.92 2.92
- Half angle of view (deg.): 16.73 9.10 6.33
- Image height: 21.64 21.64 21.64
- Length of the zoom lens : 172.73 227.50 242.86
- BF: 14.38 26.45 39.44
In fact, I could see my 28-70mm being the only RF lens I own through 2020.
hope they will release a RF 70-200mm f4 IS soon too.
when the highend mirrorless comes out i will buy it.
the EOS R is unfortunately nothing i would want beside my 5D Mk4.
or you just oversimplify things....
i wonder more that there is no mentioning of IS.
is this normal for a lens that would have IS, to not be mentioned in the patent?
L2, just in front of the aperture, is marked as IS.
Then again, I might be reading the diagram wrong, as it seems to me there's a second aperture marked as SSP.
lol.... could have sworn that was not there yesterday... i did not see it. :)
This is the article that talks about the advantage of RF lens design. It makes a lot of sense to use this design philosophy for long white lens to achieve a better balance, perhaps shorter and lighter lens along with other benefits.
I am also really surprised that Canon changed the design, as the EF was already outstanding.
Does this just mean saving production costs with less material or will there be an improvement of IQ as well?
Or is the reason the extending lens design?
There are different numbers to understand.
The "Length of the zoom lens" (172.73, 227.50, 242.86 mm) is the overall length of the optical formula from first (the front) element to the image plane. As we have a flange distance of 20 mm for the R system, the mechanical length of the lens barrel should be about (243 - 20 =) 213 mm. As we have three numbers this lens will probably have an extending lens barrel.
And this could be a reason for the different optical formula: saving barrel length if possible for a smaller system as the R system is.
The other three numbers (BF: 14.38 26.45 39.44 mm) is the distance between last lens element and the image plane.