what is the difference in using page object model insted of using page factory for the locators?

i am tring to figure out what is the effort of using the POM over the POF at the timing and at the locators way (i know it's different in the locators using) also in POM i'm using the By so what is the difference more than the writtening, i mean at the using or time or locating elements, so why its recomanded to avoid the POF?