[yt-users] take_log for plots?

Hi all, A rather simple question that I should probably already know the answer to, but here goes: Many fields are logged by default, which is as it should be. However, sometimes the range of the variable is not very large and a log plot just doesn't make a lot of sense. In a slice or a projection plot in a PlotCollection, how does one suppress (or, in the opposite case, enable) the logging of the plotted variable before saving or displaying the plot? I'm hoping there's a semi-easy way to do this without setting take_log in the field definition, but I've not come across it yet. Best, John