For Freda Ayers, 47, and Dorothy Tackett, 35, going to the White House yesterday for a reception honoring VISTA volunteers was one of the biggest thrills of their lives.

They came from Norwood, Ohio, where Tackett is a VISTA volunteer and Ayers is about to become one, for a three-day conference on poverty combined with a celebration of VISTA's 15th anniversary.

"We told the people in Norwood we'd come back with a picture of Rosalynn Carter if it killed us," said Tackett, triumphant after several attempts to have a snapshot taken with the first lady as she walked across the White House lawn surrounded by people similarly intent on taking her picture.

VISTA (Volunteers in Service to America) was one of the Great Society programs ideal for channeling the newly awakened consciousness of the '60s into something productive. More than 50,000 volunteers have enlisted since 1965, helping to start daycare centers, build parks and start community organizations. Currently more than 3,400 volunteers are on the payrolls, earning an average of $349 a month.

A list of some of the topics to be discussed at the conference is an index of the changing concerns of poverty workers: "refugees . . . racism . . . domestic violence . . . hunger and nutrition . . . health advocacy."

Walter Baker, 80, did not come to attend the conference. Baker, an unpaid volunteer in Wichita, Kan., was brought to Washington to recieve an award for his work in helping to start a new day-care center that will open July 1. Along with 21 other people, including actors Ossie Davis and Ruby Dee, former representative Michael Harrington, community organizer Saul Alinsky, and Reps. Robert Drinan (D-Mass.) and Carl Perkins (D-Ky.), Baker was honored at a ceremony at the Kennedy Center last night.

"We went around asking people in the community for their help, and I went to the city authorities," said Baker, a retired truck drive, in describing what he did to get an award. "And I wrote for a grant, and they gave us $45,000! We have a building and we'll have three shifts with 40 on each shift so that mothers can work, get off welfare and get back their self-respect. But we need two more . . ."