diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index fee6080aa..f7ea3b0c2 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -150,10 +150,6 @@ class Field(object):
         messages.update(error_messages or {})
         self.error_messages = messages
 
-        for validator in validators:
-            if getattr(validator, 'requires_context', False):
-                validator.serializer_field = self
-
     def bind(self, field_name, parent):
         """
         Initializes the field name and parent for the field instance.
@@ -264,6 +260,8 @@ class Field(object):
         """
         errors = []
         for validator in self.validators:
+            if getattr(validator, 'requires_context', False):
+                validator.serializer_field = self
             try:
                 validator(value)
             except ValidationError as exc:
@@ -907,7 +905,11 @@ class FileField(Field):
 
     def to_representation(self, value):
         if self.use_url:
-            return settings.MEDIA_URL + value.url
+            url = settings.MEDIA_URL + value.url
+            request = self.context.get('request', None)
+            if request is not None:
+                return request.build_absolute_uri(url)
+            return url
         return value.name
 
 
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 09ad376a2..0faa56718 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -428,7 +428,6 @@ class ModelSerializer(Serializer):
                     queryset=model_class._default_manager,
                     fields=unique_together
                 )
-                validator.serializer_field = self
                 validators.append(validator)
 
         for parent_class in model_class._meta.parents.keys():
@@ -438,7 +437,6 @@ class ModelSerializer(Serializer):
                         queryset=parent_class._default_manager,
                         fields=unique_together
                     )
-                    validator.serializer_field = self
                     validators.append(validator)
 
         return validators
diff --git a/tests/test_fields.py b/tests/test_fields.py
index aa8c3a68c..bbd9f93d8 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -953,6 +953,23 @@ class TestListField(FieldValues):
     field = fields.ListField(child=fields.IntegerField())
 
 
+# Tests for FieldField.
+# ---------------------
+
+class MockRequest:
+    def build_absolute_uri(self, value):
+        return 'http://example.com' + value
+
+
+class TestFileFieldContext:
+    def test_fully_qualified_when_request_in_context(self):
+        field = fields.FileField(max_length=10)
+        field._context = {'request': MockRequest()}
+        obj = MockFile(name='example.txt', url='/example.txt')
+        value = field.to_representation(obj)
+        assert value == 'http://example.com/example.txt'
+
+
 # Tests for SerializerMethodField.
 # --------------------------------