It would appear you can, but you need software to do it. There's a German program called Sofortbild, specifically for Macs, which is free, and a quick look suggests it should do what you need and then some.
There seems to be an open source program for Windows too, but I have not investigated it. Do a google search for Nikon tethering software, and you should find some options.
Disclaimer here: I have not tried any of these yet myself, though the open source windows one looks worth a further look. It might be just the ticket for microscope work.
By the way, for those with Windows (no mac version, it seems) I should report that I just downloaded a free program called DigiCam Control, and it appears on first impression to work pretty well.
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Check it out at http://www.sofortbildapp.com/
There seems to be an open source program for Windows too, but I have not investigated it. Do a google search for Nikon tethering software, and you should find some options.
Disclaimer here: I have not tried any of these yet myself, though the open source windows one looks worth a further look. It might be just the ticket for microscope work.
http://digicamcontrol.com/