Canon secured a patent (EP20120151498) for an auto-focusing algorithm (and unit) to speed up auto-focusing operations of a digital DSLR while tracking moving objects (at least this is what I understood by reading the patent). Is this the next generation of Canon’s AF systems?

A focus control method is provided that performs focus control by sensing a plurality of images of an object while moving a position of a focusing lens and determining in-focus positions in auto focusing areas located at a plurality of positions. The focus control method calculates an in-focus position of the focusing lens based on the focusing lens position at the time of reading an image signal of each of the auto focusing areas and a degree of focused state of each of the auto focusing area that is based on the image signal of each of the auto focusing areas.

The patent aims at resolving issues caused by the rolling shutter method used to control an electronic shutter. This works as follows:

Ever heard about liquid lenses? It may be the next big thing in optical engineering. Basically, liquid lenses work by applying an electric voltage to an electrolytic solution (that’s the liquid) in order to curve its surface (called meniscus). You probably are already thinking: Hey, that means no moving parts! And you are right. Liquid lenses have a series of advantages over traditional lenses. Beside not having moving parts (and thus less mechanical parts), they  respond quicker to electrical signals, they do not have a motor (you thought that USM was the big thing? Think again) and they are naturally much more silent. Just one quick note: Not having a motor means they need less electrical power, and that means the battery charge will last longer. There is a 10 minutes video at the end of the post that explains the technology. Fun to watch and good examples. Ok, let’s see the patent (it was very tiring to read :-)).

“Canon has a built-aperture mount adapter on a patent pending. Because the lens image circle can afford that extra light ghost in it may cause, Canon seems to have addressed by an internal aperture in the adapter. Canon’s next generation camera that sounds like little by little starting to move.

. Patent Publication No. 2011-107255
2011.6.2 Published
2009.11.13 filing date
. Conventional mount converter
Adjust the flange back only
Not consider the difference of the image circle, causing unwanted ghost light
. Canon patent
Aperture converter having an adjusting means
Aperture and manual operation of locks available
And electric drive aperture, the lens can be controlled by information
With a means of communication”
Egami, Google Translation from Japanese.

Canon applied for a patent in Japan for 50mm F2.8, 90mm F2.8 and 35mm F2.8 lens. Via Egami

The patent document and its summarized:
◦ Patent Publication No. 2011-107313
◦ Published 2011.6.2
◦ Filled 2009.11.16
Embodiment 1
◦ Focal distance f=50.20mm
◦ Fno=2.90
◦ Half angle of view 23.32 deg.
◦ Image height 21.64mm
◦ Lens length 84.64mm
◦ Back focus 40.01mm
◦ Macro -0.950x
Embodiment 2
◦ Focal distance f=90.40mm
◦ Fno=2.90
◦ Half angle of view 17.90 deg.
◦ Image height 29.20mm
◦ Lens length 117.18mm
◦ Back focus 65.43mm
◦ Macro -0.480x
Embodiment 3
◦ Focal distance f=35.20mm
◦ Fno=2.90
◦ Half angle of view 31.58 deg.
◦ Image height 21.64mm
◦ Lens length 102.44mm
◦ Back focus 40.10mm
◦ Macro -0.480x

Sigma Normal 50mm f/2.8 EX DG for Canon EOS
Tamron Telephoto SP AF 90mm f/2.8 Di for Canon EOS
Tokina 35mm f/2.8 AT-X M35 Pro DX for Canon EOS