(CBS News) From the days of the earliest cameras, photography has been changing the way we see the world. The Images of war captured on American battlefields a century-and-a-half ago made the Civil War very real to Americans of the time . . . and they still make that war very real to us today. Martha Teichner takes us back:
Within hours of the fall of Fort Sumter, on April 14, 1861, damage from the Confederate bombardment of it that started the Civil War had been photographed.
This was something new -- the first time Americans would see images of war, as it really looked . . . the first time true likenesses of the people who lived and died in the conflict remained as a record, profoundly shaping our understanding of the bloodiest war in U.S. history.
"When the Civil War began, photography was really in its infancy, it was just 20 years old," said Jeff Rosenheim, who heads the photography department at the Metropolitan Museum of Art in New York.
He is also curator of the exhibition, "Photography and the American Civil War."
He showed Teichner examples of portraits taken of Civil War soldiers.
"They were kept in little pocket albums, little leather albums, both by regular soldiers and by officers," said Rosenheim. "They were kept on the person, next to your heart."
Such as the portrait found in the hands of a dead soldier after the Battle of Gettysburg.
In these portraits, you see how young the soldiers were -- often, just boys -- or how ferocious they tried to look, such as the portrait of the four Pattillo Brothers, each holding a giant blade.
Photographs were already cheap -- 50 to 75 cents, with a fancy folding case, or five to ten cents printed like glorified postcards.
Subjects had to sit or stand absolutely still for as long as eight seconds then. Pictures were taken on glass plates, and printed outside in the sun.
There were field studios in tents with skylights. Very early on, photo supplies became almost impossible to get in the South, so photographers followed the Union armies, and edged closer and closer to the battlefield.
Photojournalism was born during the Civil War, though with limitations: You could take pictures before the battle, and after the battle, but not during the battle, because of the long exposures required. "The camera really couldn't capture that movement," said Rosenheim.
Alexander Gardner's camera captured the dead of Antietam, after the bloodiest battle of our bloodiest war, on Sept. 17, 1862. In fact, our bloodiest day ever, with 23,000 dead and wounded.
And then came Gettysburg the following summer -- 150 years ago this past week.
The beauty of the place belies the awfulness in Gardner's photographs, shocking to this day. You can still match locations now with then, which adds to the intrigue of a famous photographic controversy.