Casper Smart -- J. Lo's Ex Proves He's ... KNOT Afraid of Change

Casper Smart's post-Jennifer Lopez life may have fewer champagne wishes and caviar dreams ... but dude can still afford a (sorta) fancy new hair style.

Smart went full Asian on Tuesday ... strolling out of Philippe Chow while rocking a mean Samurai-styled topknot.

Casper was pretty talkative too -- giving us his pro-dancer review of J.Lo's recent twerkfest in Miami, but more importantly ... he told us what the hell he was thinking when he got his hair chopped.