The OM System 50-200mm is the world's first 100-400mm equivalent zoom lens with f/2.8 aperture. Together with a current OM System camera, it's a true wildlife and sports photography master.
The Sigma 56mm F1.4 is the longest telephoto option of a quartet of Contemporary DC DN F1.4 primes, with an effective 85mm focal length. For me, it's the best buy of the bunch, able to create dreamy portraits.