There were a few people that suggested that the differences could be due to bad focus, inconsistent focus...
I went back, did the same test with a tripod and a remote... the biggest difference was that the lighting wasn't as harsh... the difference in
the photos is there in terms of contrast however it doesn't appear to be as big a difference as in the first test. however i would like you all
to keep an open mind that in the real world more contrast can equal better AF, i initially focused with the hood on for that reason, also in
the real world focus isn't always accurate between 2 photos.
Here is the testing arena taken with the Pentax 10-17mm fish-eye to show the lighting
Here are the 50mm tests (no hood on the left, new hood on the right)
@ F1.4
@ F2.0
and @ F2.8
you may draw your own conclusions but i can see an improvement with the hood.