Interesting....
The Results of a test.... Raster in ArcMap 10.3.1 TOC,
Select ... ArcToolbox, Spatial Analyst Tools, Map Algebra...Raster Calculator
random raster appears as a selectable raster.
Enter the expression shown in the image below WITH a where clause, doesn't give an option for where, but what the hey...I put one in. The results from the Results window
Messages
Executing: RasterCalculator SetNull("random","random","VALUE>0.5") F:\Test\x2
Start Time: Fri Jun 12 23:07:49 2015
SetNull(Raster(r"random"),Raster(r"random"),"VALUE>0.5")
Succeeded at Fri Jun 12 23:07:52 2015 (Elapsed Time: 3.25 seconds)
Conclusion....surmization...
The raster calculator whips in the Raster around the inputs ( I should have been more inventive) but uses the where clause
Guess they should separate out raster calculator help or show some examples
EDIT
More inventive now to show what you can also do
SetNull("random",5,"VALUE>0.5)
Results
Messages
Executing: RasterCalculator SetNull("random",5,"VALUE>0.5") F:\Test\x3
Start Time: Fri Jun 12 23:22:30 2015
SetNull(Raster(r"random"),5,"VALUE>0.5")
Succeeded at Fri Jun 12 23:22:34 2015 (Elapsed Time: 4.12 seconds)
Fun with the raster calculator