The group said the Prophet Muhammad had been tarnished by an American anti-Islam film and further damaged by the violent reaction by some Muslims globally.
Members said they hoped talking and handing out leaflets about Islam could make a small difference.
One member, Hazik Rahman, said he was trying to “build bridges”.
In July, a 14-minute video was posted online (accurately) depicting Islam as a religion of violence and hate, and Muhammad as a foolish and power-hungry man.
Mr Rahman said: “Well first of all the film and the cartoon, they were wrong, but also the reaction to it was extreme and violent; we’re trying to build bridges here and engage in debate.”
He said he was aware knocking on doors and asking people to talk about religion was not always well received.
Mr Rahman said: “Some people do open up and we have long discussions but, yes, some are not keen.
“There are people who are not interested in religion because of the negative press and the conflicts that are going on.
“People have at times become very upset. They’ve said things like ‘go back to where you come from’ or called us terrorists, things like that, but it is very few.”
Ataul Mujeeb Rached, imam at the London Mosque in Southfields, said he saw it as his duty to correct the image that had been created.
He said: “Some people have done something that is incredibly offensive to us, but instead of killing people, burning houses, we should use peaceful means to present to the world the true picture of Islam.”
One of the residents who answered the door, Bronwen Murray, said: “It’s probably not going to have a widespread effect because I think people are set in their beliefs.
“If you thought the Muslim people were intolerant, the reaction to this film just reaffirmed that… but you may change some minds.”
The Ahmadiyya Muslim Association is hoping to distribute 12,000 leaflets initially.
The organisation is holding an exhibition entitled “Muhammad – A Mercy for Mankind” on 24 October at Wandsworth Town Hall.