Just wanted to share some thoughts on some recent news about lenses.
TAMRON 70-200 2.8 VC
DXO recently released its test results for the Tamron 70-200 2.8 VC for Nikon. DXO found that the Tamron 70-200 (22 P-mp on a D800) is sharper than the Nikon 70-200 2.8 VR II (20 P-mp) and the Nikon 70-200 f/4 VR (21 P-mp).
I would be interested in the Tamron but am very concerned about the size and weight. If it's too inconvenient to carry with me I will likely end up not using it very often. For now, my preferred telephoto lens is still the Nikon 85 1.8G (19 P-mp on a D800 or D600).
SIGMA 18-35 1.8
Last week, Sigma announced the pricing and availability for the Sigma 18-35 1.8, which will have a street price of $799 in the U.S. and will be available in July. I had been interested in this lens as a complement to the Nikon 85 1.8G. The price is not low but I was actually expecting it to be higher. Nonetheless I will probably pass on this lens. The reason is that the Sigma 18-35 1.8 is equivalent to having a 24-50 2.8 full frame lens in terms of depth of field and effective sensitivity. In that regard, I already have the Nikon 28-70 2.8D which I'm happy with and in addition I already have the Sigma 35 1.4. If you ask me, I would prefer the Sigma 35 1.4 over a 24-50 2.8.
My problem is that if I use the Sigma 35 1.4 on my D600, I don't have a great telephoto alternative for the D7000. The 85 1.8G perhaps, but it's kind of long for my purposes.
Anyway here are Photoworld's hands-on impressions of the Sigma 18-35 with sample shots.
ALTERNATIVE TO TOKINA 11-16
I'm currently using the Tokina 11-16 2.8 (on the D7000) to complement my 85 1.8G (on the D600). I like the Tokina but it's a little shorter than I'd like on the long end. I am contemplating replacing the Tokina 11-16 with a Sigma 10-20 3.5. The 30mm equivalent on the long end would be useful to me. When I had the 28 1.8G I liked the focal length and I think it would be a good compromise between having a 28mm and 35mm lens. I've also had the Sigma 10-20 f/4-5.6 which I found quite sharp, so I am pretty sure that the 10-20 3.5 will be sharp enough for me. Besides, according to DXO, the Sigma 10-20 3.5 and Tokina 11-16 are both about as sharp (8 pmp on a D7000). The Sigma is slower than the Tokina but the D7000's high ISO performance is decent, so I don't feel I need a fast wide angle lens as much as I needed to with the Fuji S5.