Story highlights Cameraman gives a rare glimpse of fighting in the city of Homs

"My eye! my eye!" shouts a wounded man

Estimates put military defectors' strength at more than 1,000 in Homs

A freelance cameraman who visited Homs recently put together a video that provides a rare glimpse of life in the embattled city and an even rarer close-up of the opposition movement in Syria.

At the headquarters of the government secret police, the cameraman -- who uses the name Mani to avoid retribution by the government if he returns -- finds himself in the thick of a battle. Some 200 members of the Free Syrian Army, made of military defectors, are involved in the attack. They explode a bomb below a rooftop position, where government snipers are trapped.

In the video, portions of which CNN aired Friday, the opposition appears organized, their members communicating by walkie-talkie and engaging in fierce fighting. Casualties are taken via minibus to a makeshift field hospital, where they are placed on thin mats on the floor. "My eye! My eye!" shouts one man whose eye had been targeted by a bullet.

Mani's camera follows opposition fighters as they enter the government building, where room-to-room and stairwell-to-stairwell fighting ensues.

Finally, as bullets continue to fly, the opposition fighters make off with boxes of ammunition so they can return to fight another day.

After 20 hours, 15 opposition fighters have been killed, 40 wounded.

The next day, the building is gutted by local residents.

Not all the battles are so bloody. Mani says they are sometimes able to persuade government forces to cede ground without firing a shot.

"They always try, first, to make negotiations work," Mani says. "They talk with the officer, they talk with the soldiers, and they offer them either to defect, either to surrender, and leave the checkpoint. And sometimes it works."

Civilian volunteers are plentiful; more and more, they are being joined by defectors from government forces, Mani says.

Across Homs, some estimates put the FSA strength at more than 1,000. Each neighborhood has its own command, but they sometimes combine forces to improve their odds against the much larger and better-armed government forces.

Some soldiers who don't desert nevertheless sell their weapons or ammunition to the opposition, the cameraman adds.

"There are many people who are in favor of them, who feel they are in favor of the opposition," Mani says.

Down one street, his camera shows a long line of residents lined up outside a bakery for bread.

"Because of the snipers, people are taking more than they need," says the man who is handing out the loaves. "That's why it's crowded."

Two days earlier, in a nearby district, hundreds of residents fill the streets to mourn the deaths of 138 people in overnight shelling by government forces. Without enough coffins to go around, many of the dead are wrapped in white shrouds.

"Shelling people is what cowards and scoundrels do," the imam says. "Be careful of gathering in public."

"We are going to heaven!" the crowd chants, their fists pumping the air. "There are millions of us!"

Mani comes upon a woman just as she learns that her son has been fatally shot by a sniper. "He is my son! My rock!" she wails. "I have no man! He is my man!"

Her son, a former supporter of the regime, bears a tattoo on his chest that says "Assad." Next to that is the entry point for the bullet.

A couple of blocks away, the shelling that has pockmarked much of the city has spared a district where many residents belong to the Alawite sect to which President Bashar al-Assad belongs.

Homs is now a patchwork divided along sectarian lines.