For EFLw=4.4mm, Pixel_Sizew=1.4um and Pixel_SizeT=1.0um, the tele camera EFL required is 6.3mm. Typical lens designs having such EFL will result in a module height exceeding 8mm.
In order to enable zoom dual cameras in a slim form factor, Corephotonics developed and patented a compact narrow-angle telephoto lens in which the TTL would uncommonly be smaller than the EFL. While doing so, we keep the large aperture (up to F/2.2) and minimize the EFL to TTL ratio (down to 0.87) without any compromise in optical quality or manufacturability.
The result enables 2x-3x optical zoom cameras with superior low light performance and high resolving power, which complies without breaching module height constraints dictated by smartphone industrial design