I've been having some issues with my D800 and Tamron 90mm where I just couldn't get focused in for a crisp image. I'm still having problems with that but I think I'm slowly making progress. I'll keep trying to hone my technique. These were taken with an Avast porthole which obviously is a bit harder to stabilize without the tripod.
DCS_3658-2 by Chris Johnson, on Flickr
DCS_3648-2 by Chris Johnson, on Flickr
DCS_3660-2 by Chris Johnson, on Flickr
DCS_3667-2 by Chris Johnson, on Flickr
DCS_3663-2 by Chris Johnson, on Flickr
DCS_3658-2 by Chris Johnson, on Flickr
DCS_3648-2 by Chris Johnson, on Flickr
DCS_3660-2 by Chris Johnson, on Flickr
DCS_3667-2 by Chris Johnson, on Flickr
DCS_3663-2 by Chris Johnson, on Flickr