Hi Brian,
Thanks for the report. Yes, this is a known issue in low-level VisAD/IDV, and thus is part of McIDAS-V. According to the thread at
http://www.unidata.ucar.edu/support/hel ... 02176.html, what happens is that when you zoom in too far, you zoom through the back clipping plane. And as also noted there, when you get to the point where the image data drops out (goes black) you can click Projections->Use Displayed Area menu to reset the projection to the area in view and zoom in closer.
I was told that in most cases you should be able to zoom in farther when using McV 1.0beta5 than you could zoom when using 1.0beta4. We anticipate that 1.0beta5 should be available soon (hopefully within the next couple weeks).
Thanks,
Barry