So, over on the other forum there is complaint that the new 40-150 should be faster, say starting at f2.8 or something like that. Looking at the specs, the lens seems really small for what it is. At any rate, the complaint was associated with DOF and the slow aperture. For a telephoto lens, I would agree that we could all use more light, but shallower DOF? Some numbers with subject 10 feet away: 150mm @ f5.6 gives me .22 feet of acceptable focus on :43: 25mm at @ f2.0 gives me 2.9 feet on :43: 150mm @ f2.8 gives me 1.32 inches on :43:. APSC 200mm at f5.6 is .15 feet FF at 300mm at f5.6 is less than an inch. At less than an inch with a subject, like a bird, 10ft away, would be difficult to shoot, IMHO. Do we really need shallower DOF when using a telephoto lens?