Brian Arthur Campbell Mathers pleaded not guilty on Tuesday in Brisbane District Court to two charges of making child exploitation material and one charge of possession.
A jury took just over an hour to reach its verdict on Wednesday following a trial that lasted one-and-a-half days.
Mr Mathers had been accused of placing his phone against the bathroom window of his home in Newport, north of Brisbane, and filming the girl on two occasions between December 2020 and October 2021.
The girl claimed she saw the phone being used to film her on the second occasion but police were not able to retrieve any deleted data from Mr Mathers' Samsung device.
Defence barrister, Dominic Nguyen, had earlier told the jury his client made an "honest mistake" when filming the girl in December 2020 or January 2021 as he thought his wife was in the shower at the time.
Crown prosecutor Elise Adams had accused Mr Mathers of giving contradictory explanations to his wife and police about what he did with the video file afterwards.
Before they retired to consider their verdict, Judge John Allen told the jury members they could find Mr Mathers not guilty if they determined the girl's responses during her testimony were "odd".
The girl gave her testimony via pre-recorded video that was played to the jury while the court was closed to the public.
After the verdict was handed down, Mr Mathers was released from the dock and hugged his supporters in the public gallery.
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