If you are convicted of an offence that carries a maximum punishment (even if you did receive the maximum) of 10 years imprisonment OR you were sentenced to 6 months imprisonment, there will be immigration consequences.
However, if you are inadmissible to Canada by reason of a criminal record, you may still be allowed to enter Canada if you:
Demonstrate to an immigration officer that you meet the legal terms to be deemed rehabilitated . One may be deemed rehabilitated depending on the offence, how long has passed since the sentence ended, and if subsequent crimes were committed;
Applied for rehabilitation and were approved;
Were granted a record suspension (formally known as a pardon ); or
Have a temporary resident permit and it has been less than 5 years since the end of your sentence OR you have valid reasons to be in Canada.