Originally posted by catastrophe The Sigma 10-20mm does sound pretty good resolution wise, but I heard the flare resistance is pretty bad on the lens and the rendering of the sun. The Tokina is probably the best choice for FF but no filter option kills it for me.
Also, I've been thinking about the real advantage of a FF sensor in terms of noise. FF sensor does have a 1-1.5 stops advantage over APS-C in terms of high ISO, but since the depth of field is lower, for night landscape/astrophotography where I don't want to compromise the depth of field, wouldn't the FF sensor need to bump up 1-1.5 f stops to achieve the same DOF as a APS-C sensor? If so, that actually eliminates any high ISO advantage of a FF sensor.
For landscape if you shoot anything from 10-20mm at f4 and smaller, focused on anything over 3.5 meters from your sensor, everything is already hyperfocal. This is the same whether you use APS or FF, so DOF is moot for most landscapes.
Your logic is correct though, if you use moderate (not UWA) focal lenghts for your landscape and need to focus on objects that are 1 - 2meters to infinity, then you do eliminate the high ISO advantage as you need to stop down more. However, this doesn't mean that in this situation APS-C is better, just equal. Using FF I can always stop down and eliminate my high ISO advantage to get APS-C equivalent DOF, however I cannot reduce DOF to become FF-like when using APS-C.
Personally when using FF I do find it kind of annoying that I have to turn the wheel all the way to f 5.6 to get decent dof at 28mm
FF will always have more options for shooting compared to APS-C of the same gen except in weight and size (cost is debatable and depends on the FL / featureset, see my lens comparisons above). The weight and size argument
imho only matters when lenses get as small as the DA limiteds, but that's for my use only. Pentax also has the advantage of small WR lenses. Canikon does not have any small WR lenses.
Pentax is possibly releasing their best body ever and I'm talking about FF in an internet forum.... I feel dirty now, so I think I'll stay away