Canon has released technical patents for the built-in teleconverter with lightweight and good optical performance, including the "600mm F4", "400mm F2.8" and "300mm F2.8" examples of built-in 1.4-fold teleconverter.
Patent Publication No.: P2022142979
Patent Publication Date: October 3, 2022
Patent Name: Optical System, Lens Device, Imaging Device
It is an object of the present invention to provide an optical system with a variable magnification optical system that can be inserted into the main optical system and removed from the main optical system, and to obtain good optical performance while reducing the weight of the entire system.
When using a system with built-in zoom optical system, the only way to achieve good optical performance while reducing the weight of the entire system, including zoom optical system, is to select a suitable insertion position for the zoom optical system. However, it is also important to properly configure the main optical system. From the perspective of lightweight and optical performance.
focal length 389.00mm
F Number 2.91
Half-view angle (°) 3.18
Image height 21.64mm
Lens length 406.00mm
Post-focal length 53.83mm
0
Use built-in teleconverter equivalent focal length is 560mm F4
focal length 544.00mm
F Number 4.19
viewing angle (°) 2.28
image height 21.64mm
lens length 406.01mm
rear focal length 53.83mm
2. Example 2 (600mm F4)
focal length 582.00mm
F Number 4.12
viewing angle (°) 2.13
image height 21.64mm
lens length 486.10mm
rear focal length 81.91mm
0 Use built-in teleconverter to be equivalent to (840mm F5.6)
focal length 814.80mm
F Number 5.88
Viewing angle (°) 1.52
Image height 21.64mm
Lens length 486.10mm
Post focal length 81.91mm
10
3. Example 3 (300mm F2.8)
focal length 300.00mm
F Number 2.91
viewing angle (°) 4.12
image height 21.64mm
lens length 320.00mm
rear focal length 49.68mm
0
use built-in teleconverter, the equivalent is (420mm F4)
focal length 420.00mm
F Number 4.12
viewing angle (°) 2.95
image height 21.64mm
lens length 320.00 mm
rear focal length 49.68mm
Many people will have questions. Canon has launched 4 telephoto cannon lenses, and is still so anxious to make new cannons? In fact, those four telephoto cannons are all optical designs of the old SLR camera lens 400/2.8 and 600/4. Later, a 2x plural mirror was added to each of these two lenses, which became two cannons, 800/5.6 and 1200/8. Although the focal length of the 800 and 1200 lenses has increased, their optical quality has declined.
Then this new cannon is a new design lens. Although it uses a built-in teleconverter, it is a new generation of products designed according to the latest optical ideas.
On the contrary, Nikon has launched the Z 400mm f/2.8 TC VR S with built-in teleconverters. The rumored Z 600mm will also have built-in teleconverters, but Canon seems to be considering using the ultra- teleconverter lens built-in teleconverter. The 400mm example has a full length of 38.6cm, excluding the flange back, which is almost the same size as the Nikon Z400mm.
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