Sam Taylor-Johnson likens directing 'Fifty Shades' to walking on a knife edge

London: 'Fifty Shades of Grey' helmer Sam Taylor-Johnson has admitted that movie has been truly challenging and she feels wrung dry after directing the flick.

The 47-year-old director said in an interview with a magazine that she is literally going out of her mind and she has seen this film over a thousand times and she is now in a blancmange, the Daily Express reported.

She continued that but the nuances within i.e. the tiniest shift look, blink of an eye, etc. can make all the difference and flip it into the wrong territory and it was like walking on a knife edge.

The 'Nowhere Boy' director said that she wanted to protect her vision and that's the hardest thing as there are so many voices.