The Sun's picture editor made "hardly any" checks when approving cash payments to a long-serving reporter's source, a court heard.
John Edwards (pictured, Reuters), 50, said he had to trust journalists "implicitly" and only has time to focus on important emails and stories.
He has no memory of a request by reporter Jamie Pyatt for payment to a serving soldier at Sandhurst, he said.
But Edwards conceded he would have been worried if he had seen the email, asking for a £250 "bung" to the soldier.
"What checks did you make or instruct your deputies to make to ensure cash was going to the right person for the right thing?" asked prosecutor Oliver Glasgow.
Edwards told Kingston Crown Court: "Hardly any – it's complete trust there with Mr Pyatt.
"My day was busy, there were a hell of a lot of decisions which needed making during the day.
"When I was growing up on The Sun picture desk, Jamie Pyatt was the news editor for two years.
"Anything Jamie was doing did not need policing by me, I would trust Jamie.
"I can't forensically analyse – it would be impossible to do my job.
"I have to look and say that needs my attention, that doesn't – an email from Jamie is not something that's ringing any alarm bells."
Pyatt, 51, emailed head of news Chris Pharo and Edwards on 15 March 2006 asking for two payments, to a police officer and to a source who provided a picture of a Household Cavalry soldier facing a murder charge.
"I want to look after the soldier on this as Prince Harry will be joining at his base in the near future," he wrote.
"Can I bung £250 to the policeman and £250 from Picture Desk to the soldier?"
Edwards told the court: "Jamie Pyatt was the only reporter who would email like this.
"He understood the system with the budget.
"If I've got a former news editor here, and some reader trying to flog me a picture they may not own, I've only got a certain amount of time.
"I can't forensically go through everything, there has to be some slack somewhere."
Edwards is accused of conspiracy to commit misconduct in public office by paying Pc Simon Quinn and Broadmoor healthcare assistant Robert Neave for pictures that were published in The Sun.
He is in the dock with The Sun's former managing editor Graham Dudman, 51, head of news Chris Pharo, 45, deputy news editor Ben O'Driscoll, 38, and reporters Pyatt and John Troup, 49, who all face similar corruption charges.
Pyatt has admitted paying Pc Quinn and Neave for stories on 24 occasions, but said the information leaked was in the public interest and not confidential.
In February 2010, Pyatt emailed Pharo and Edwards asking for money to pay a source after a story from Broadmoor maximum security hospital.
He revealed his "tipster" worked at the facility, and said: "Would like to welcome aboard with £750 split with Picture Desk."
Edwards said he would not have read this email thoroughly, but added: "I'm seeing nothing wrong here at all, I'm looking at an email from a trusted colleague.
"He had been there longer than me, he was there when I joined."
Glasgow asked: "Were you and the picture desk in the habit of paying cash to sources to keep them onside?"
Edwards replied: "No."
Glasgow continued: "Given you did not pay cash as a bribe to keep them onside, had you read this email would you agree you would have been worried about it?"
Edwards said: "I'm not sure about this, there was no check list in the office of people we could and we couldn't pay.
"I'm not entirely 100 per cent sure how I would have felt."
He told jurors the picture desk made a handful of cash payments a year, but he may have referred a request for payment to a public official to the deputy editor or the editor.
He said other senior Sun reporters would ask him for money at times, and said he often approved payments just to help other departments balance their budgets.
Pharo, of Wapping, east London, denies four counts of conspiracy to commit misconduct in public office.
O'Driscoll, of Windsor, Berkshire, and Dudman, of Brentwood, Essex, both deny three counts of conspiracy to commit misconduct in public office.
Edwards, of Hutton, Brentwood, Essex, and Pyatt, of Windsor, deny two counts of conspiracy to commit misconduct in public office.
Troup, of Saffron Walden, Essex, denies one charge of misconduct in public office.
All six defendants have been cleared of an overarching conspiracy to pay public officials, while Pharo was found not guilty of paying a Sandhurst soldier.
Edwards coped with the irrational demands of Rebekah Brooks in her "pressure cooker" newsroom with his dignity and integrity intact, his father told the court.
Famed Sun Royal photographer Arthur Edwards said his son John lived in constant fear of being sacked under Brooks' editorship, but maintained a happy demeanour throughout.
"After 40 years working at The Sun, I know first-hand the kind of pressure he was under while working in an atmosphere best described as a pressure cooker, with an editor not always rational but always demanding," he said in a statement to the court.
"Under Rebekah Brooks failure was never an option."
Edwards managed a large team of photographers, dealt with hundreds of emails a day, and was expected to be available around the clock to make decisions, he said.
"John knew that he was only one mistake away from losing his job, having seen so many others suffer that fate.
"Despite this often intolerable pressure, John is known for his calm and cheerful disposition.
"He never shouted at colleagues, was always respectful to others, and maintained his dignity when others lost theirs."
Edwards paid tribute to his son's honesty, integrity, loyalty and devotion, adding that he and other Sun staff had attended court each day to show their support.
In a heated exchange during his evidence, Edwards defended his position that he trusted experienced reporters in their decisions.
"I was quite happy, and still would be, to trust staff reporters, staff photographers, the news desk, the Bizarre desk, the features desk, and the city desk," he said.
"Without trust, it's impossible for me to do my job and I can't stress that enough.
"There has to be trust."
Glasgow countered: "That's because everyone knew what was going on."
But Edwards replied: "That's not true – it's not as if it was a six month casual reporter who had been there for two weeks, he had been there for 28 years, he used to be the news editor, why would I have to worry about what he's doing.
"I'm looking at him as a person I can completely and utterly trust."
Edwards approved a payment for Pyatt to a "police contact" for a December 2010 story that Ann Summers founder Jacqueline Gold had been poisoned, simply replying: "Yes of course" and asking the reporter to sort out the paperwork with his assistant.
Glasgow suggested: "If a reporter came to you saying I need to pay a police officer in cash, you would just say no problem?"
Edwards said: "If I trusted that reporter, yes.
"I'm responsible for a lot of things, I've given you my answer and I couldn't feel more strongly about it."
He argued he had more pressing concerns than scrutinising Pyatt's payment request.
"There's no way I can go into any great detail, I'm looking at a hundred things to do, thinking about the picture list, thinking about what mood Rebekah is in, tons of stuff on my mind," he said.
"I've got no reason at all to mistrust Jamie Pyatt or any of the other staff reporters or freelance reporters."
Glasgow suggested: "You must have a reason to mistrust him now.
"Now you can't trust him can you?"
Edwards replied: "I think, on everything I've seen at this trial, there's probably a lot I would do differently."
Edwards also suggested that the phrase "police contact" could refer to a contact who drinks in the pub next to the police station, or an officer's rugby teammate.
He described his arrest as "the most traumatic of my life", adding: "I was like a rabbit in front of the headlights."
Giving evidence for him, friend Colin Bailey described how Edwards had supported the cause of his daughter Tilly as she battled rare genetic disorder Neonatal-Onset Multisystem Inflammatory Disease.
He said Edwards had helped publicise their cause in The Sun, and arranged for his daughter to meet Simon Cowell back stage at The X Factor.
"John is not someone who looks for credit, but he deserves a lot more credit especially for what he's done for us," he said.
"Not many people talk to my daughter the way he does.
"Most people approach Tilly, see her in the wheelchair and they struggle to communicate with her, dissecting her with their eyes and making her feel horrible.
"John is one of only a few people who go up and be nice, genuinely happy and talk to her in a normal way."