Sigma has used Photokina to showcase four new lenses.

First up is the 24-70mm f/2.8 EX DG which is equipped with a built-in HSM (Hyper Sonic Motor).

The 14-element-in-12 group lens includes Extraordinary Low Dispersion (ELD) and Special Low Dispersion (SLD) elements.

It will come in Sigma, Nikon, Canon, Pentax and Sony AF fits at a price yet to be announced.

Also new is a 50mm f/1.4 EX DG HSM lens designed for use on Four Thirds digital SLRs. Features include a minimum focusing distance of 45cm, maximum magnification of 1:7.4 and full-time manual focus override. It will cost £379.99.

Sigma has also unveiled 10mm and 4.5mm fisheye lenses for Pentax and Sony digital SLRs with an APS-C size imaging sensor. Both include a maximum aperture of f/2.8 and HSM.

The 4.5mm f/2.8 EX DC HSM, priced £599.99, has an angle of view of 180 degrees ?in all directions?, producing a circular image within the frame (when used with a DSLR with an APS-C size sensor).

?The minimum focusing distance is 13.5cm and maximum magnification of 1:6 make it particularly useful for close-up photography,? according to the firm.

While, the 10mm f/2.8 EX DC HSM will cost £449.99 and is said to deliver a diagonal angle of view of 180 degrees.

SLD glass helps to minimise colour aberration on both lenses.

Sigma 24-70mmSigma 50mmSigma 10mmSigma 4.5mm