Political campaigns may be significantly off-base when it comes to the number of people they say are present at campaign rallies across the country, a CBC News investigation shows.

Both the Conservatives and Liberals have held major rallies since the beginning of the federal election, with the Conservatives in particular emphasizing the size of their events.

CBC News's visual investigations team hand-counted people in images taken at four rallies across the country — Conservative rallies in Surre…