Those who've been around DSLRs for a while will know that until recently noise came in badly at relatively low ISOs. My D70 was probably only good for 4-500 ISO and the D300 ISO 800-1600 at a push. Invariably you would end up under exposing to get a decent shutter speed and then bring up the exposure in post, which introduces loads of noise and is a bad way to do things. Alternatively you drop the shutter speed and are disappointed by the blurred results.
With the advent of cameras like the 24mp DX bodies and pretty much any current FX model, noise is much less of an issue. That said, it's only recently that I've got comfortable with this new world and started setting my camera with the aperture and shutter speed I want and letting the ISO sort out the exposure. Therefore if I want 1/1000 shutter speed I dial it in and if it results in ISO 3200 then so what. After it's been through Nik Define noise removal and generally post processed they can look pretty good.
The shutter speed point is important, especially with these high resolution sensors and longish lenses. If you want something sharp and handheld at 400mm+ you really should aim for 1/1000 sec or better even if it's not moving as the sensor will show any movement that you introduce. YMMV.
With the advent of cameras like the 24mp DX bodies and pretty much any current FX model, noise is much less of an issue. That said, it's only recently that I've got comfortable with this new world and started setting my camera with the aperture and shutter speed I want and letting the ISO sort out the exposure. Therefore if I want 1/1000 shutter speed I dial it in and if it results in ISO 3200 then so what. After it's been through Nik Define noise removal and generally post processed they can look pretty good.
The shutter speed point is important, especially with these high resolution sensors and longish lenses. If you want something sharp and handheld at 400mm+ you really should aim for 1/1000 sec or better even if it's not moving as the sensor will show any movement that you introduce. YMMV.