Tamron just announced a “revolutionary new 150-600mm Ultra-Telephoto Zoom Lens for full-frame and APS-C format DSLR cameras”. The new SP 150-600mm F/5-6.3 Di VC USD (Model A011) boast a super tele range of 150 to 600mm. The (variable) maximum aperture of 5-6.3 has made it possible for the designers to keep the weight down (it weighs less than 2kg), whilst still allowing enough light to pass through for most autofocus systems to work*1.
This all-new ultra-telephoto zoom lens features VC (Vibration Compensation) image stabilization, USD (Ultrasonic Silent Drive), and eBAND (Extended Bandwidth & Angular-Dependency) Coating to reduce the unwanted light reflections that cause flare and ghosting. It will be available with a Canon, Nikon, or Sony mount (the Sony model comes without VC as that is built into the Sony cameras already). If you live in Japan, the lens is expected to be available from the 19th, the rest of the world will follow soon thereafter. Price indications for this lens seem to be around $1069, which is pretty cheap for such a nice focal range! If image quality is good, this may be a great lens for sports and wildlife shooters!
*1 Modern Canon and Nikon cameras actually allow fully functional autofocus of up to f/8 (for some of the AF points). For most cameras, however, AF is fully functional only using lenses with a maximum aperture of up to f/5.6 (or even bigger). Using a lens with a smaller maximum aperture (e.g., f/6.3, like this lens), does not mean AF will not work at all, just that it won't work as fast/reliable as when using a lens with a larger max aperture in similar cases.