Sony has patented the design of a series of bright zoom lenses, including a roughly F1.8-2.8 lens that would give 26-100mm equivalent coverage on a 1"-type sensor. The designs suggest the company intends to further develop its RX range of compacts. Such a lens would allow for a camera that made better use of its comparatively large sensor, even at the long end of the zoom.  

The company has been awarded three patents, including one for an innovative dual focus element design. The two focus elements (one positive and one negative) move relative to one another to allow the lens to offer high magnification and close focusing - two properties that are usually in tension with each other.

The patent points out that the use of single small, light internal focus elements to allow rapid autofocus is limited because there isn't much room within the lens for the sole focus element to move around. This limits the ability for the lens to focus on a wide range of focus distances. Adding a second focus element that moves relative to the first one allows the camera to adjust the range over which it focuses, without increasing the distance over which a single element can move.

Six different variations of the design are proposed, offering different balances of lens range and consistency of lens speed. Examples given in patent 2014-66944 are:

Proposed lens:Focal lengthAperture RangeEquivalent FL, assuming 1"-type sensor
Example 1 9.58 - 19.82 - 41.00mm F1.87 - 2.49 - 3.30 26 - 55 - 112mm
Example 2 9.58 - 19.82 - 41.00mm F1.87 - 2.27 - 3.01 26 - 55 - 112mm
Example 3 9.58 - 18.55 - 35.91mm F1.87 - 2.23 - 2.89 26 - 51 - 98mm
Example 4 9.60 - 23.40 - 57.03mm F2.04 - 2.57 - 3.67 26 - 64 - 156mm
Example 5 9.58 - 19.82 - 41.00mm F1.87 - 2.26 - 3.00 26 - 55 - 112mm

We find examples 2, 3, and 5 particularly interesting. We hope these patents will be converted into a product at some point, assuming the two focus group technology can live up to its promise.