What is difference between self.get_serializer and Serializer object in Django rest framework?

Question

Currently I have started learning django rest framework and I came accross below kind of code for getting serializer object.

1)serializer = self.get_serializer(queryset, many=True)
2)serializer = MyDataTypeSerializer(queryset, many=True)

By using above two method I am able to get almost same kind of output so I have tried to find difference between those but not able to find any.

I have used above method likewise in my viewset.

class MyDataTypeViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):
    serializer_class = MyDataTypeSerializer
    permission_classes = [IsAuthenticated]
    queryset = MyDataType.objects.all()
    def get_queryset(self):
        return self.queryset.filter(user_id=self.request.user.id).order_by('-created_at')

    def list(self, request, *args, **kwargs):
        queryset = self.get_queryset()

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            serializer = self.get_paginated_response(serializer.data)
            return return_success(serializer.data)
        serializer = self.get_serializer(queryset, many=True)
        #serializer = MyDataTypeSerializer(queryset, many=True)
        return return_success(serializer.data)

Please if anyone knows let me know difference between these two methods and how to decide which method to use in which condition.

Thanks,

Answer 1

get_serializer() also takes care of passing in the viewset's serializer context, and calls get_serializer_class() to figure out which serializer class to use.

Unless that function has been customized from the viewset default as linked by Andrew in the comments, and serializer_class = MyDataTypeSerializer has been set,

serializer = self.get_serializer(queryset, many=True)

is exactly equivalent to

serializer = MyDataTypeSerializer(
  queryset,
  many=True,
  context=self.get_serializer_context(),
)