I'm a hobby photographer and I'm going on a 5-6 day safari trip in Tanzania. I'm looking for advice on gear upgrade for the trip. I currently have D80 with 14-24mm f2.8, 50mm f1.8, 70-200mm f2.8 VR2 in addition to my SB800, tripod and a couple of sigma lenses (30mm f1.4 and 105mm f2.8 macro).
I have read that 300mm on DX is minimum for safari, but my budget is limited. I could afford the 300mm f4 + a Nikon TC but that is stretching it. I'm planning on upgrading to FX in the future, but for this trip I'd rather upgrade my reach. Besides I would rather want the rumored D700s/x or D800.
The lenses I'm considering are:
nikon 300mm f4 + a TC
sigma 100-300mm f4 + a TC
sigma 50-500mm (bigma the old without os)
sigma 150-500mm (bigmos)
I'm currently leaning towards the sigma 150-500mm. I have read lots of reviews of all the lenses but I still struggle to decide. I'm aware of sigmas rather bad reputation in QA, but I'm very happy with my 30mm. It is also about half the price compared to Nikon 300mm f4 + TC, which leads to more money for other stuff like beanbags, extra memory cards and extra batteries. Any advice would be appreciated.
I noticed that you recommend to wait on both the 80-400mm and the 300mm f4 in the price watch. How likely is It that an upgrade of either of these will be available in stores before June? No chance?