Judge MacAskill said sentence was not designed to mirror the horrific consequences of the crash.
He said that not much more would be achieved by community work. Earl was also disqualified from driving for 12 months.
The court heard that Mrs Hubbard did not seek reparation.
Jean Hubbard, 82, can't recall anything of the fatal smash.
She woke up in Oamaru Hospital worried that maybe she was to blame for her husband's death.
But it was Earl who was charged, with careless driving causing death and careless driving causing injury.
When Earl's trial began in early June at Oamaru District Court, sitting in Timaru, the court heard how the Hubbards had set off from their Timaru home to visit relatives in Dunedin.
They stopped to eat ice creams in Glenavy, in the deep south of Canterbury, shortly before the smash.
A witness told the court of his concerns over Earl's ``erratic'' driving shortly before the crash.
He said that in his rearview mirror, he saw Earl's red Holden Rodeo 4WD ute drift into the Hubbards' oncoming white Honda Jazz, causing the crash.
Judge MacAskill rejected defence claims that Mrs Hubbard had been distracted eating the ice cream while driving, and it was Earl that was trying to avoid the head-on crash when the collision occurred at about 1.15pm.
``It is reasonable to infer _ and I do infer _ that the defendant ceased to control his vehicle as a result of drowsiness or having fallen asleep,'' Judge MacAskill ruled.
Earl should have been aware of his drowsiness and stopped driving until he was sufficiently alert.
``His failure to do so was careless,'' said Judge MacAskill.
Today, Earl's Dunedin-based lawyer John Westgate said he was ``so sorry'' for what happened and its ``catastrophic effects''.
While Earl accepted the judge's findings that he was responsible for the crash, he was struggling to accept that he was drowsy or had nodded off at the wheel, Mr Westgate told the court.
He has been driving for 25 years, had a clean record, and ``doesn't make a habit of driving while tired'' and if he had been drifting off, he would have pulled over.
He was in no hurry that day, Mr Westgate said, and had had a good night's sleep.
Earl has told APNZ he intends to appeal the finding that he was drowsy or had fallen asleep at the wheel.
At the time of his death, Mr Hubbard's firm, Aorangi Securities was being investigated by the Serious Fraud Office (SFO) and was placed in statutory management in June 2010, owing investors up to $100 million.
The SFO laid 50 charges against Mr Hubbard under the Crimes Act, but those were dropped shortly after his death.
In a statement, Mrs Hubbard welcomed the case's conclusion so that both the Hubbard and the Earl families could now ``move on with their lives, as her late husband would have wanted''.
``She bears no ill will towards Mr Earl or his family arising out of the accident,'' the statement said.
