Ok, here is a shot...a chipmunk from about 33 feet(about 10 m) away at 400mm.  DOF is close to 9 inches(23 cm).   Lighting was lousy, the sun behind coulds and all overcast.  As it was, the shot was like this: ISO 800, F/5.6, 400mm, 1/25 sec.   Who can take a critter at 1/25 sec? Not me!  Not a figgity chipmunk for certain.

Regardless of the slight movement of the critter and terrible lighting, this does show the converter works pretty well.  The image is brighter than it looked at the time in all the overcast.

I will look for more light next time...perhaps the sun will show where it generally does on this spot and where this fellow generally shows up at about 7 AM for a moment or two.

Color looks fine as does sharpness except for the slight movement of the chipmunk.  So much for a trial shot at a bad time to try it.      I do like the teleconverter.       Tom.