For cops, cameras can change everything.

Mounted on patrol car dashboards, clipped to police uniforms or wielded by witnesses with cellphones, cameras have altered the American landscape when it comes to public perception of how police deal with people. Black people in particular.

We've seen scenes gone viral: A man in a police choke hold repeatedly says he can't breathe and ultimately dies. An unarmed man is shot in the head by a cop in a traffic stop. A man running away from an officer is shot from behind and killed.

Back when the idea of police cameras started gaining favor as an unbiased eye on what actually happened, some officers balked. Wouldn't it chill the discretion good cops use daily?

Turns out, cameras cut both ways. There are terrible, damning videos that lead to murder charges — and videos that convince authorities that police were not at fault. And there are videos that show something else going on out there, too.

Just this week, someone snapped a shot of an apparently unaware Massachusetts cop walking a 95-year-old woman home from the polls, her arm tucked into his burlier one.

And Disney could not have made up the one out of Gainesville: An officer investigating a complaint about noisy kids playing basketball does not roust them, his dashcam shows, but instead joins them to shoot some hoops.

He could not have possibly imagined how viral that video would go, or that no less than Shaquille O'Neal would show up and join him to play with those kids again.

Or that within a couple of months, he would be launching a Basketball Cop Foundation GoFundMe page to raise money for balls, hoops and equipment in neighborhoods where kids could use them.

Closer to home, Tampa police compiled a video of body camera footage — released last week on YouTube — that they say tells a truer tale of what police do daily.

Amid the foot chases and encounters with some surly citizenry, you see an officer affably changing someone's tire and another fixing a woman's wheelchair. One cop tries to corral a baby alligator back into an apartment complex pond.

Police Body Cam Video They Aren't Showing On The News, it's called.

Sixty of the department's 1,000 officers have been outfitted with body cameras as part of a University of South Florida study that runs through May.

So how useful can cameras be when it comes to telling the truth?

There was no dashboard or body camera to record what happened the night last October when a plainclothes Palm Beach Gardens police officer shot and killed a musician who was waiting for a tow truck with his broken-down SUV on a darkened highway off-ramp. That tragedy had no impartial, dispassionate witness who might have been able to give the world a better picture of what happened.

Those cops-caught-doing-good videos don't change the fact that the public deserves complete and transparent answers in every officer-involved shooting.

But those videos are exactly the kind of police work officers say no one ever sees because the uglier, deadlier stories overshadow them.

Except, it turns out, we do.

Sue Carlton can be reached at carlton@tampabay.com.