Sigma is rumored to release some super telephoto prime lenses in the 2014. According to CR, Sigma is working on big prime lenses as below:
- Simga 300mm f/2.8 OS
- Sigma 400mm f/2.8 OS
- Sigma 500mm f/4 OS
- Sigma 600mm f/4 OS
The price of these lenses will cheaper than Canon and Nikon Version. We will see officially announcement in 2014.