Sigma has launched two new fisheye lenses at Photokina 2008 - firstly the 4.5mm F2.8 EX DC HSM, which is the the first circular fisheye lens exclusively for use with APS-C size digital SLR cameras, and secondly the 10mm F2.8 EX DC HSM, a diagonal fisheye lens for Pentax and Sony fitting cameras.

The 4.5mm F2.8 EX DC HSM has an angle of view of 180 degrees in all directions, and when used in conjunction with digital SLRs with APS-C size image sensor, it produces circular image within the frame.

The minimum focusing distance of this lens is 13.5cm and it has maximum magnification of 1:6, making it a good choice for close-up photography. Its combination of SLD (Special Low Dispersion) glass, super multi layer coating and inner focusing system provides superior image quality.

The 10mm F2.8 EX DC HSM on the other hand, produces a diagonal angle of view of 180 degrees, creating images with exaggerated perspective and distortion.

This lens has a minimum focusing distance of 13.5cm and maximum magnification 1:3.3, allowing subjects to be as close as 1.8cm from the lens’ front element. The combination of the exclusively designed integral hood and the super multi-layer coating minimises flare and ghosting for top image quality.

The 4.5mm F2.8 EX DC HSM is priced at £599.99, while the 10mm F2.8 EX DC HSM will cost £449.99. Release dates are to follow.