In practice, the difference between a D and a non-D is some subtle changes with flash. Occasionally the flash meter has difficulty figuring out the subject distance, which is quite relevant with flash, and the D functionality sorts this out. I think this will be incredibly rare in macro work, to the point of vanishingly infrequent, but it *might* become visible when (if) the lens is used as a general purpose telephoto.
If you consider that none of the manual focus lenses have any D functionality, and that flash seems to work just fine with them, I'd say that D functionality is almost entirely optional even if you do use flash, and completely irrelevant if you prefer to work only with available light.
_____ Brian... a bicoastal Nikonian and Team Member
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As mentioned already the only time you "might" see a difference in your photos when using a D versus non-D lens is when using flash.
This difference can be seen some times when the cameras meter is set to matrix and the flash is set to TTL BL. Since the non-D lens does not provide distance information it cannot be used to fine tune the exposure accuracy of the exposure as it can with a D lens. Also 3D color matrix metering is not used with a non-D lens , only standard color matrix metering which does not include distance information. I find that generally when using a non-D lens with flash that the exposure will be slightly less than with a D lens and probably in the order of -1/3 EV.
If you set the camera exposure meter to Spot then the flash will go into standard TTL mode and the exposure between a D or a non-D lens will be the same.
When using the macro lens for close up or macro photos, with or without flash, the differences are negligible.