While optical design and the latest ultra-low dispersion glass can make for some very small lenses, a couple of manufacturers have added some clever tricks to make their lenses even more compact. One solution is Sliding Lens System first developed by Pentax and seen on many of the companyâ€™s Optio range of compact camera. This same design is used by several other manufacturers to produce zoom lenses for very slim cameras. When the lens is retracted, a block of lens elements moves out of the light path and slots into a space beside the rear element, allowing the whole lens to fit into a space of about 15mm.
Equally ingenious is the Folded Optics System, first seen on the Konica Minoltaâ€™s Dimage X series. In this system, the zoom lens is mounted vertically within the camera body, and looks out trough a prism angled at 90 degrees, like a submarineâ€™s periscope. This has the advantage that the lens doesnâ€™t need to be extended before it can be used, allowing extremely fast start-up times.
Sony uses a similar system developed by Carl Zeiss on its T-series cameras, as does the Casio Exilim EX-V7.