A peeping Tom who used his phone to film a woman in the shower told police he was waiting for a call while up a ladder searching for his cat and made the recording accidentally.
Dean Pointing, 26, of Frenchay, later pleaded guilty to voyeurism by recording a private act and was handed a four-month jail sentence, suspended for two years.
Judge Michael Longman told him: "You lied when you were spoken to and you lied when the footage was recovered. Your explanation must have stretched your powers of imagination.
"I have read the victim personal statement and this has affected her deeply. She has continuing feelings of vulnerability and paranoia."
Pointing must also carry out 180 hours of unpaid work and was made the subject of a two-year restraining order. He must sign as a sex offender for seven years.