Note that you do not have to change the CSM setting to use the aperture ring with MF lenses. The setting only applies to AF (CPU) lenses with aperture rings because there is a choice between using the command dial or the aperture ring to set aperture.
There is one quirk of using the aperture ring with the D300, I don't know if it is also the case with a D300s. LiveView will not work with AF lenses that have aperture rings, if the aperture ring is enabled. The aperture ring on manual focus lenses works fine with with LiveView, but AF lenses must be used with the aperture ring disabled for LiveView.
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