"You were talking about the poor relationship you had with her and that you were resentful towards her," Judge Ian Mill said in court today.
"You planned to record her in the bathroom when she was showering."
The reasons for the man's resentment were not given in court.
He first began offending against her in May that year. He waited until she went into the bathroom, then went outside and pressed his cellphone against the tinted bathroom window. The phone was able to film through the tinted glass, but the victim could not see it.
He recorded the girl 59 times over the next seven months, capturing footage of her naked in the bathroom and emailing some of the clips to himself.
Over the months, he "refined" his technique in filming, and improved the quality of his footage, Judge Mill said.
He would sometimes watch the videos - which were usually between five and 50 seconds long - with his co-defendant, and the pair would make derogatory remarks about her.
He sent the clips to his co-defendant on 12 occasions, which was the basis for the representative charge of publishing intimate visual recordings.
The offending was eventually discovered when the victim's mother used the man's laptop, and came across the videos he had saved.
"You admitted to creating the video using your cellphone because you were resentful towards the victim," Judge Mill said.
"This was repetitive, premeditated offending against a young person who was vulnerable, who could have expected to be protected by you. The videos were played whilst you ridiculed her in the presence of another person.
"This was a terrible breach of your trust or the trust she must have had on you as her stepfather."
The offending happened in the victim's home, where she "should have felt safe".
The man has separated from his wife, and now lives in Wellington. He remains in fulltime employment in his own business.
According to a pre-sentence report, he expressed "great remorse" for the offending and said he had no sufficient excuse for his actions.
"You recognise now that your actions were extreme."
The man maintained, and the report writer appeared to accept, that the offending was not sexually motivated and that he was not attracted to children in that way.
Crown prosecutor Jamie O'Sullivan said the victim had "limited knowledge" of the offending.
Judge Mill convicted the man and sentenced him to seven months on home detention. He is not to associate with the victim and cannot have contact with his own teenage daughter except on terms agreed to by a probation officer.
The judge granted permanent name suppression because he was satisfied naming him could create a real risk the victim would be identified.
"She certainly does not deserve that to happen if your name is published."
