When Brazilian photographer Claudia Andujar started working with Yanomami people in the Amazon rainforest in the 1970s, most of them did not know what a camera was.
Andujar spent most of that decade and more in northern Brazil photographing the Yanomami, one of Latin America's most remote indigenous tribes.
She learned their language and joined their daily routines hunting and gathering food in the largest indigenous territory on the continent, an area roughly the size of Belgium.
"Most of them had never seen a non-Yanomami person. They were very vulnerable," the 84-year-old told the Thomson Reuters Foundation from her home in São Paolo.
They are in danger again today, despite decades of efforts to protect them, their advocates say.
The Yanomami's land rights are under threat by a proposed constitutional amendment that would enable changes to the boundaries of current Indian reserves and allow private-sector involvement in agriculture, mining and other projects, they say.
"Indigenous land rights of Indians across the country would be drastically weakened," said Sarah Shenker, a campaigner with Survival International, a London-based charity.
The Yanomami live in small communities of up to around 300 people. They hunt, live off rainforest fruit and plant vegetables such as sweet potatoes in gardens.
There are thought to be roughly 32,000 Yanomami in Brazil and Venezuela today, according to Survival International.
Andujar said she could only gain access to Yanomami villages by helicopter, as there were no roads, and only forest paths connected the isolated communities.
She said she began photographing the tribe simply because it interested her as a photojournalist.
The Yanomami are naked but for dyed loin cloths, and they traditionally paint their bodies.
They are best known for using wooden sticks as facial piercings. The position of the stick, which normally pierces the lips and nose, is determined by a person's gender.
In the early 1980s, Andujar began taking pictures to be used for immunization records. With two doctors, she spent three years photographing the villagers one by one to identify them for health cards because the Yanomami people do not have names.
Andujar became their ardent defender.
"I got very engaged in protecting the territory, the life and culture of the Yanomami people," she said.
Illegal Gold Mining
In the 1970s, illegal gold miners began to encroach on their territory, bringing diseases such as malaria which killed off a large portion of the tribe.
Activists say the miners also introduced mercury poisoning into the Yanomami's ancestral lands.
In 1978, Andujar helped found the first non-governmental organization, the Pro-Yanomami Commission (CCPY), to represent them.
In 1992, their lands were officially mapped out by the Brazilian government, affording them some protection from illegal miners and others, such as cattle ranchers.
And Andujar and the Yanomami people bonded, despite their different lives. She respected them and their culture, she said.
The photographer, born in Switzerland but of Hungarian descent, fled Europe after World War II, lived in New York and settled in Brazil in the 1950s.
"With me they were always very gentle, but I also was very gentle with them. They weren't worried about me," Andujar said.
"Indigenous people start to change when they feel that somebody is trying to interfere in their way of life, their culture, their beliefs. But since I was a lone woman they didn't fear me," she added.
After nearly half a century, Andujar is still at work on their behalf.
Her latest project was mounting a permanent display of some 500 photographs at a contemporary art gallery called Inhotim in the Brazilian state of Minas Gerais.
She spent five years working on the project and hopes it will serve to educate the public about the Yanomami.
The proposed constitutional amendment, known as PEC 215, threatens to shift the power to demarcate indigenous land to Congress from Brazil's federal government.
Many members of Congress are linked to mining, energy and agro-business interest groups, a worrisome development, activists say.
The amendment was approved in October by a commission of lawmakers but requires consent from Brazil's lower house and needs to pass the Senate twice. If the amendment goes ahead, indigenous people's land rights would be significantly weakened, activists say.
"Existing territories could be undone or could be opened up for large scale mining, for military bases, for dams, for roads," said Shenker of Survival International.
Some small-scale mining could lead to more mercury poisoning, the introduction of diseases and the destruction of fish stock, upon which the Indians depend for food, she added.
High levels of mercury poisoning are already present in some Yanomami people, according to a study by Brazil's Oswaldo Cruz Foundation, a public health institute, and the Socio-Environmental Institute, a non-profit group that researches indigenous rights.
In some villages, nine in 10 people are contaminated by mercury caused by illegal gold mining, the study said.
"The present situation is very critical again," Andujar said. "The government of today has absolutely no interest in preserving indigenous lands."
Although her direct involvement in their lives ceased 15 years ago, due to her ill health, she said she stays in touch with her old friends.
"We talk on the phone still. We have a very friendly relationship, even today," she said.