Nikon 25-50 F/4.0 versus 28-50 F/3.5 ?

Both lenses seem to be highly reviewed, but I just cant imagine that the 28-50 (being so much smaller) can have the same optical quality as its larger (but older) cousin the 25-50.

Anybody know the actual T stops of these lenses?

I want to use this for landscapes AND manual focus video work

Get the 25-50. One of the only zooms I own, and I use it on D3/3s as well with Canon 7d for video. Excellent lens, better than the 28-50, it is sharper and has virtually no color fringing, and you won't miss the 1/3 stop. Landscapes at F11 are superb, and it has decently smooth bokeh near wide open. The only thing is that it doesn't focus super close, but a +1 diopter helps out in that area if needed. You won't be disappointed, it is one of Nikon's very best manual zooms.