I'm going to assume you took a 5ft unrack for the sake of the camera. 1/2ft would be ideal. 5ft might as well be the Trail of Tears of lifting.
You're not using your hips effectively. Have you watched this video? Watch the timing of the hips. His abs and knees are tight and locked. Then he takes a big breath and throws his hips forward, rebounds off of them, and presses the bar overhead. Hips and then press.
Also, buy some lifting shoes and a belt.