Originally posted by Xiong 1/25 shutter
That is a very slow shutter speed for hand-held. Your blurry picture problem is most likely related to that.
Originally posted by Xiong In full manual mode, auto focus wouldn't even lock.
??? 'Full manual mode' would normally mean you are manually focussing, and have the camera mode dial set to M.
TAv isn't fully manual, just quasi manual because while you may be in control of aperture and shutter in TAv, ISO is still being adjusted by the camera according to the program line. And of course your AF settings (AF-S, AF-C, MF) and AF pattern (11/5/spot etc) are controlled outside of your exposure mode.