Visible crew/equipment: When Bumpy hires Shaft to find his daughter, Bumpy gives Shaft an envelope with money, and when Shaft stands up you can see the bulge of the hidden microphone and wire at the front of Shaft's turtleneck sweater. When Bumpy leaves the office Shaft turns around and there's a bulge at the back of his waist, which is presumably the mic transmitter. (00:26:10)
Continuity mistake: At the beginning, Shaft is crossing the street and a taxi jumps around between cuts. In the overhead shot, he passes the taxi and walks in front of a taxi, but in the level shot, he is in front of a brown car and giving it the finger.
Continuity mistake: A fight happens inside Shaft's office: a shattered glass noise can be heard, but the door is intact. That is, until the fight is over and the plaid coat man flies off the window. At that point the front door glass is shattered as well. Moreso, a shattered glass noise is heard when someone ends up against the wall, but the frames don't appear broken at any point. (00:10:35 - 00:11:10)
Revealing mistake: During the credit sequence with the iconic Isaac Hayes theme, occasionally passersby look into the camera, but given the camera placement and the amount of people involved it's hard to label that as mistake. At one point tho, around the 2:50 mark, some tall dude walks into frame and waves a "black power fist" for the camera - he couldn't be greeting Shaft with the gesture because he does it when Richard Roundtree has already walked well past him. (00:02:50)
Factual error: The calendar in the police office indicates Tuesday January 27th and Thursday January 29th. That was in 1970, but this story takes place in 1971.