Chris Keane says the on-screen actions of creepy lensman Lou Bloom, played by Jake Gyllenhaal, are repugnant and a sensational Hollywood fantasy.

"I found the film offensive professionally, and I hope the public can differentiate between a Hollywood sensational thriller and what we do out there in the real world," said Keane.

"He has no morals and he does everything to an extreme."

Among the Bloom character's actions are: Arriving at a car crash before emergency services, he moves a bloodied body so he can get a better shot.

He sabotages a rival cameraman's van, causing him to crash, then films a close-up of the rival's bloodied face on the stretcher.

Bloom arrives before police to a home invasion, enters the house to film two bodies, and he keeps filming rather than giving first aid when he finds a third victim still breathing.

In reality, Keane, 60, is a proud professional who has covered overnight crime, accidents and fires for over 15 years.

He says after Princess Diana died in a 1997 car crash,chased by paparazzi in Paris, Keane would be regularly abused by the public as "scum".

Three years ago, while filming an assault victim at Caulfield train station, a teenage thug who thought he shouldn't be there threw a full, energy drink can at Keane, breaking his jaw.

Keane says the public needs to know that Nightcrawler is "extraordinarily unrealistic".

"It's repugnant. It's so over the top and so 'Hollywood treatment', but there's going to be people out there that view it and go [to real cameramen], 'those scumbags'."

Keane says any cameraman who crossed police tape or shoved a camera between a paramedic and the wounded "wouldn't last five minutes". Police would arrest them, or send them to film from a mile away.

He says good operators work with emergency services. If they're patient and respectful, authorities will let them film closer and give interviews when they're ready.

His footage is shared between the ABC and channels 7, 9 and 10, but Keane is employed by the ABC, so unlike Bloom, he doesn't hawk his footage to the highest bidder.

It can be adrenaline-fuelled. On one recent night, , Keane drove to Tallarook, north of Melbourne, to film a woman being rescued after falling down a cliff, then rushed back to Docklands to film evacuations from an apartment building fire.

Unlike Bloom, Keane doesn't speed and has never arrived at a scene before police, but if he did and there was a wounded person, he would put aside his camera to help them.

A colleague did, in fact, once come across a man critically injured in a hit-run in South Yarra, and resuscitated him.

Keane works five days every second week, from 8pm to 6am. He has been to "some pretty bad scenes" but has learned to switch off, is married with two sons and maintains hobbies outside of work such as photography and leadlighting.

It is not pleasant filming firefighters pulling teenage bodies from car crashes. But it can show the consequences of speeding, drinking, or fooling around on the roads.

Recently he filmed a motorcyclist who covered his own number plate so he could "go at stupid speeds" down the Princes Highway. The rider crashed into a car and was badly injured.

Keane says one positive of his job is "showing the skills and abilities of all the emergency services working together to save someone".

Keane urges young people to "please take on board what we're showing you, and what the police are telling you, and be there at Christmas for the family".