The High Court at Auckland heard that the first victim, who was known to Needham, received text messages from him in 2010 purporting to be from a colleague called Adam.
"Adam" gained the woman's trust and she sent him naked photos of herself.
In 2011, Needham created another fake identity called Chris, who claimed to have brought a secondhand laptop with photos of her on it.
Posing as 'Chris', Needham told the woman he would upload the pictures to Facebook unless she provided him with more.
The next woman was blackmailed in 2012, after Needham obtained photos of her wearing lingerie when she was a teenager.
When police caught up with Needham he admitted his offending and said he was sorry, something that Justice Duffy said showed his remorse.
She gave him credit for that and his lack of previous convictions.
Crown prosecutor Dale Dufty said Needham's offending happened when he was a "fully grown man who should have known better".
APNZ