Police found more than 4,400 images and movies of children on multiple phones, tablets and laptops belonging to Kevin Simon Ford, aged 23.
He admitted three charges of sexual activity, two of sexual assault, and five of making images of children.
He also admitted one of inciting a girl to engage in sexual activity at Taunton Crown Court.
Det Con Tony Davis described Ford, of no fixed address, as a "vile man who took advantage of his victims' families in order to carry out horrific abuse and sexual offences on girls, some of which he filmed".
"The sexual abuse of children and the viewing and sharing of indecent images are abhorrent offences and we're committed to supporting victims and bringing offenders to justice," he said.
A paedophile who abused young girls and filmed some of his crimes has been jailed for 15 years.