Nyquist Sampling for Z stacks

If information is to be preserved in all three dimensions, it is important that the images are collected with appropriate x, y and z dimensions. These dimensions are determined by the Nyquist sampling theorem which, in essence, says that, to resolve an object, we must sample that object 2.3 times more frequently than its dimensions. Another way to say this is that our voxel size needs to be a minimum of approximately 0.4 x the dimensions of that object. For example, if the theoretical resolution limit in the lateral (x,y) plane is 0.2μm, then we must use a pixel dimension of 0.2μm x 0.4 = 0.08μm (or 80nm) in that plane. Similarly, if the z dimension resolution limit is 0.5μm, then our best z step should be 0.5μm x 0.4 = 0.2μm (200nm). This means our final microscope setup should be collecting images with voxels that have dimensions of 0.08μm (x) x 0.08μm (y) x 0.2μm(z).