He said he was initially asked by another security guard to seek out the footage of then-England rugby captain after a "situation" at the door of the bar Dixon worked security at.
Dixon has begun giving evidence in his defence at his trial by jury in the Invercargill District Court.
He is charged with accessing a computer and obtaining, without right, property, after he posted online footage of Tindall with a woman who was not his wife, Zara Phillips, in the Altitude Bar in Queenstown during the Rugby World Cup in 2011.
Dixon does not deny accessing the computer, but says he honestly believed he had the right to do so.
He told his lawyer John Westgate that during his seven years working security at the bar his understanding was always that anyone working there could access and do what they wanted with CCTV footage.
He said after he asked a receptionist to download the footage, people around town started telling him they had heard Tindall was "up to no good" in the bar that night, and that if anyone had footage it could be worth money.
He then researched what such footage would be worth, but was not going to sell it, he said.
Dixon said that downloading the footage and seeking a price for it was a project for the benefit of the Base/Altitude Bar and that he never intended to sell the footage directly himself.
He said he posted the footage in the end on the internet, because it became apparent that Base wanted instead to itself drip-feed it to the media over a longer period, and he was not happy with the prolonged pain that would cause Tindall's wife, Zara Phillips.
He denied the suggestion from Ms Thomas that actually he did it because he was angry after he found out that the media agency he was dealing with would not buy the footage without Base's authorisation, and Base had refused that, so he realised he was not going to make any money from it after all so he would stop anyone else from doing so.
