Har haft detta liggande på datorn och kopierar in nedan hämtat från en tråd på nikonians:
And now, two other issues - P Mode and Flash...
In P mode (which I never use) the camera works in what may seem to be an odd way, causing you to think that something has gone wrong.
With Auto-ISO off the camera behaves as expected in P mode and the full range of exposures for your lens is available to you.
With Auto-ISO on, the camera I is limited by the minimum shutter speed you select in the Auto-ISO settings.
In other words, with Auto ISO off and 100 ISO selected, the camera will, in P mode, give you choices of aperture/shutter speed combinations from your maximum to minimum aperture settings.
With Auto-ISO on the maximum aperture available is the same but the minimum aperture/shutter speed combination is limited by the minimum shutter speed you set when configuring Auto-ISO. Once you get to those limits, turning the command wheel just takes you into a "dead click zone" where nothing happens.
Example.. Lens with f4-f22 range - 100 ISO
P mode Auto-ISO off
Combinations of aperture/shutter speed available from 1/400 @ f4 to 1/15 @ f22 using 100 ISO
P Mode Auto-ISO on - minimum shutter speed set = 1/125
Combinations of aperture/shutter speed available from 1/400 @ f4 to f7.1 @ 1/125 using 100 ISO
In the latter case, once into the "dead click zone", each dead click of the command dial takes you further away from your start or end point. For example, if you click 8 clicks past the f7.1 above, not only will nothing happen but you will need to click 9 clicks in the opposite direction before you see a change in the exposure reading.
In the above example the ISO remains at 100 because the camera will never change the ISO unless it needs to because it has run out of avilable apertures or shutter speeds.
And, finally Flash...
Sometimes the camera can give unpredictable results when using Auto-ISO with flash in TTL mode. I don't know definitively why this is but it's probably because there are two unknown variables to be taken into account at the same time - the FV plus the ISO (How can the camera determine exactly what ISO is required with what flash power? It can calculate one unknown parameter, but not two at the same time. At least that's my theory). I never use Auto-ISO with TTL flash.
In TTL-BL, Auto-ISO is not a problem because the EV is calculated for the whole scene as normal and the flash is acting only as a fill-in.
