For these photographers, the images live within them.
There's Rodrigo Telón Yucute, for example. He focuses on the sound of the voices, raises a camera and snaps off a shot, capturing an image of a couple laughing as they sit on a yellow park bench.
He shows it to the subjects, but cannot see it himself. The photographer-in-training has been blind for nearly 30 years.
"When I was young, I met a lot of people and it always caught my attention how they would take photographs to keep as mementos," Telón said. "I like to take photographs to capture a moment that I can later share with my family and friends so they can see what my life is like."
Telón was a 22-year-old guerrilla fighter in his home country of Guatemala when a land mine exploded beneath him, ripping apart his left forearm and destroying his eyesight.
After years of rehabilitation, he learned Braille and how to use a white cane to get around. Now 51, Telón is fulfilling his longtime wish of taking photographs.
He is one of 30 visually impaired or blind people learning photography with the help of the Mexico City foundation Ojos Que Sienten, or Eyes That Feel.
Founded five years ago by professional Mexican photographer Gina Badenoch, the foundation has been teaching the blind to express in photographs how they perceive the world. Her students use their hearing, touch, smell and taste to choose their subjects and create their images with the help of digital cameras.
The main purpose of the photography workshop is to teach blind people they can do things that would seem impossible, Badenoch said.
"It helps them feel part of society again. It helps them be seen and be heard again," she said.
For many of the new photographers, the most rewarding part is having their sighted friends describe the images.
"Being able to share something I made and hear people who are seeing your photograph describe what you created in your mind is something I enjoy tremendously," said José Manuel Pacheco Crispín, a 33-year-old university student who began losing his sight at the age of 16 because of a retinal degenerative disease.
Now a photography teacher at the foundation, Pacheco was part of the first group to take the workshop five years ago. After years of struggling to accept his new, sightless life, Pacheco said photography has empowered him and helped him to sharpen the senses he does have.
"It has helped me to break barriers and to keep having crazy ideas," said Pacheco, who recently climbed to the top of Iztaccihuatl, a 17,159-foot (5,230-meter) volcano near Mexico City. He and other visually impaired friends made the climb guided by Erik Weihenmayer, the first blind person to reach the summit of Mount Everest in 2001.
Photography doesn't come easy. Beginners often leave out the heads or legs of their subject, but with practice they learn to improve their images. In a sense, they're photographing the sounds they hear or the smells they sense.
The sun's warmth helps them know where to place themselves to photograph their subject. They may touch a flower to sense its shape before photographing it, or listen intently for the wind blowing through leaves to locate a tree.
They ask people they are photographing to talk to them so they can figure out how high or low on their body to place the camera. They then hold the camera against their foreheads or chests for stability.
"My hearing, my smell, all my senses are alert when I'm taking a photograph," said José Antonio Domínguez, who has taken scores of photos of his guide dog Boni, a 3-year-old golden retriever.
While talking at a Mexico City restaurant, Domínguez explained the information he was picking up from his hearing.
"To my right, the waitress dropped the knives first and then the forks," he said.
Each blind photographer has a project to work on for two months. Domínguez said he wants to photograph people who help him as he navigates the chaotic streets of Mexico City.
Telón, who lost his parents and two brothers during the civil war in Guatemala and has lived in Mexico since 1990, will focus part of his project on an 8-year-old girl who lost her arm and who refuses to wear her artificial limb.
"I want to tell her my story and how I got accustomed to using my artificial arm," Telón said.
He may also tell her about a daughter he saw for the last time 29 years ago, when she was 6 weeks old.
"When I left to join the guerrilla she was starting to smile," Telón said. "That's a photograph I keep in my mind."
Based on reporting by the Associated Press.