What in the flash is going on??

Today I pulled out the D90 and fitted up the SB-800 flash as I wanted to take some shots of some gear I have.  Annoyingly, each shot I took was coming out way too dark.  I pride my self on being able to find quick solutions to photographic problems, but this wasn't the case this time.  

 Firstly I checked the CLS setting as I had been playing around with it a while back.  Nope, all OK.  Did some additional reading on CLS to see if I'd forgotten anything, but alas it was just fine.  Checked all the SB-800 menus - all correct.   Replaced the flash batteries - Still the same problem.  Checked the flash compensation on the flash - No, set at +1/3 EV, which weirded me out as it was 2-3 stops too dark.  

Frustrated, I put the camera down for 10 minutes, and after I came back I noticed the +/- flash exposure compensation on the camera.  I gave it a push and '-3' came up.  So I changed it back to '0' and viola!  Correct exposure!  Hallelujah!!   

Even for a serious amateur, sometimes there are so many menus in a modern DSLR, finding the correct answer to the problem takes time. 

Leica 90mm f4 collapsible Elmar M on Sony NEX 5n

This is the Leica 90mm f4 collapsible Elmar M mounted on the NEX 5n with an adapter, and interestingly, the lens can almost completely collapse into the camera, save about 5mm.