Sigma....

Sigma, founded in 1961 at bandai, fukushima, japan specialist in manufacturing camera, lenses and flash...beside produce theri product to work with canon, nikon, pentax, konica minolta, sony and olympus..

some of their product..
Zoom lenses:

Wide-angle Zooms
10-20mm f/4-5.6 EX DC HSM
12-24mm f/4.5-5.6 EX DG Aspherical HSM
15-30mm f/3.5-4.5 EX DG Aspherical
17-35mm f/2.8-4 EX DG Aspherical HSM
20-40mm f/2.8 EX DG Aspherical
Standard Zooms
24-60mm f/2.8 EX DG
24-70mm f/2.8 EX DG
24-70mm f/3.5-5.6 Aspherical HF
24-135mm f/2.8-4.5 Aspherical IF
28-70mm f/2.8 EX DG
28-70mm f/2.8-4 DG
28-105mm f/2.8-4 DG
28-105mm f/3.8-5.6 Aspherical IF
28-135mm f/3.8-5.6
28-200mm f/3.5-5.6 DG Macro
28-300mm f/3.5-6.3 DG Macro
Telephoto Zooms
50-500mm f/4-6.3 EX DG HSM
70-200mm f/2.8 EX DG MACRO HSM
70-200mm f/2.8 EX DG HSM
70-300mm f/4-5.6 DG MACRO
70-300mm f/4-5.6 APO DG MACRO
80-400mm f/4.5-5.6 EX OS
100-300mm f/4 EX DG HSM
120-300mm f/2.8 EX DG HSM
135-400mm f/4.5-5.6 DG
170-500mm f/5-6.3 DG
200-500mm f/2.8 EX DG (2x teleconverter included, allowing 400-1000mm f/5.6)
300-800mm f/5.6 EX DG HSM

Prime lenses:

Wide-angle Primes
8mm f/3.5 EX DG Circular Fisheye
8mm f/4 EX DG Circular Fisheye
14mm f/2.8 EX Aspherical HSM
15mm f/2.8 EX DG Diagonal Fisheye
20mm f/1.8 EX DG Aspherical RF
24mm f/1.8 EX DG Aspherical Macro
28mm f/1.8 EX DG Aspherical Macro
Macro Primes
Macro 50mm f/2.8 EX DG
Macro 70mm f/2.8 EX DG
Macro 105mm f/2.8 EX DG
APO Macro 150mm f/2.8 EX DG HSM
APO Macro 180mm f/3.5 EX DG IF HSM
Telephoto Primes
APO 300mm f/2.8 EX DG HSM
APO 500mm f/4.5 EX DG HSM
APO 800mm f/5.6 EX DG HSM
DC Lenses for APS-C
10-20mm f/4-5.6 EX DC HSM
17-70mm f/2.8-4.5 DC MACRO
18-50mm f/2.8 EX DC
18-50mm f/2.8 EX DC MACRO
18-50mm f/3.5-5.6 DC
18-125mm f/3.5-5.6 DC
18-200mm f/3.5-6.3 DC OS
30mm f/1.4 EX DC HSM
50-150mm f/2.8 EX DC HSM
55-200mm f/4-5.6 DC