Documentary photographer Dorothea Lange had a favourite saying: “A camera is a tool for learning how to see without a camera.” And perhaps no one did more to reveal the human toll of the Great Depression than Lange, who was born on this day in 1895. Her photographs gave us an unflinching — but also deeply humanizing — look at the struggles of displaced farmers, migrant labourers, share-croppers and others at the bottom of the American farm economy as it reeled through¹ the 1930s.

Lange worked for the Farm Security Administration in the 1930s, chronicling rural poverty across America and the agency's efforts to provide relief. Her most famous photo is often referred to as “Migrant Mother.” Shot in 1936 at a campsite full of unemployed pea pickers in Nipomo, Calif., the image features Florence Owen Thompson, a poor farmworker flanked by two of her seven children. [...]

But you don't need to read Lange's notes to sense this desperation. So much is conveyed in the worry etched² on Thompson's face, worn far beyond her 32 years at the time the photo was taken.

Before she began documenting the travails of the poor, Lange was a portrait photographer for the well-to-do in San Francisco. So she knew that images of individuals would have far more emotional impact than those showing barren³ landscapes [...].