Ko te arotahi CCTV varifocal he momo arotahi kāmera e āhei ai te whakarerekē i te roa arotahi. Ko te tikanga o tēnei ka taea te whakarerekē i te arotahi kia puta he koki tirohanga rerekē, kia taea ai e koe te whakanui ake, te whakaiti rānei i te tirohanga ki tētahi kaupapa.
He maha ngā wā ka whakamahia ngā karāhe arotahi rerekē i roto i ngā kāmera haumaru nā te mea ka taea te whakamahi i ngā karāhe arotahi rerekē hei whakawhānui i te tirohanga. Hei tauira, ki te hiahia koe ki te aroturuki i tētahi wāhi nui, ka taea e koe te whakatakoto i te karāhe arotahi ki tētahi koki whānui ake hei hopu i te tirohanga. Heoi anō, ki te hiahia koe ki te arotahi ki tētahi wāhi, ki tētahi mea rānei, ka taea e koe te whakanui ake hei tiro tata atu.
Ki te whakatauritea ki ngā arotahi pūmau, he kotahi te roa arotahi pūmau, he nui ake te whānuitanga o ngā arotahi rerekē e pā ana ki te whakatakotoranga kāmera me te kapinga tirohanga. Heoi, he nui ake te utu i ngā arotahi pūmau, ā, me nui ake te whakatikatika me te whakatikatika kia pai ai te mahi.
Ki te whakataurite ki tētahiparfocal("pono") he arotahi whakanui, e noho tonu ana i te arotahi i te mea ka whakanui te arotahi (te roa arotahi me te hurihanga whakanui), he arotahi rerekē te arotahi a te arotahi he arotahi kāmera he roa arotahi rerekē e huri ana te arotahi i te mea ka huri te roa arotahi (me te whakanui). He maha ngā arotahi "whakanui", inā koa i roto i te take o ngā kāmera arotahi-pūmau, he arotahi rerekē, e hoatu ana ki ngā kaihoahoa arotahi he ngāwari ake i roto i ngā tauwhitinga hoahoa whatu (te awhe roa arotahi, te whakatuwheratanga mōrahi, te rahi, te taumaha, te utu) i te whakanui parfocal.