diff --git a/docs/api-guide/fields.md b/docs/api-guide/fields.md
index f95608afb..a7ad4f70c 100644
--- a/docs/api-guide/fields.md
+++ b/docs/api-guide/fields.md
@@ -290,9 +290,9 @@ A date and time representation.
 
 Corresponds to `django.db.models.fields.DateTimeField`.
 
-**Signature:** `DateTimeField(format=None, input_formats=None)`
+**Signature:** `DateTimeField(format=api_settings.DATETIME_FORMAT, input_formats=None)`
 
-* `format` - A string representing the output format.  If not specified, this defaults to the same value as the `DATETIME_FORMAT` settings key, which will be `'iso-8601'` unless set. Setting to a format string indicates that `to_representation` return values should be coerced to string output. Format strings are described below. Setting this value to `None` indicates that Python `datetime` objects should be returned by `to_representation`. In this case the datetime encoding will be determined by the renderer.
+* `format` - A string representing the output format. If not specified, this defaults to the same value as the `DATETIME_FORMAT` settings key, which will be `'iso-8601'` unless set. Setting to a format string indicates that `to_representation` return values should be coerced to string output. Format strings are described below. Setting this value to `None` indicates that Python `datetime` objects should be returned by `to_representation`. In this case the datetime encoding will be determined by the renderer.
 * `input_formats` - A list of strings representing the input formats which may be used to parse the date.  If not specified, the `DATETIME_INPUT_FORMATS` setting will be used, which defaults to `['iso-8601']`.
 
 #### `DateTimeField` format strings.
@@ -321,7 +321,7 @@ A date representation.
 
 Corresponds to `django.db.models.fields.DateField`
 
-**Signature:** `DateField(format=None, input_formats=None)`
+**Signature:** `DateField(format=api_settings.DATE_FORMAT, input_formats=None)`
 
 * `format` - A string representing the output format.  If not specified, this defaults to the same value as the `DATE_FORMAT` settings key, which will be `'iso-8601'` unless set. Setting to a format string indicates that `to_representation` return values should be coerced to string output. Format strings are described below. Setting this value to `None` indicates that Python `date` objects should be returned by `to_representation`. In this case the date encoding will be determined by the renderer.
 * `input_formats` - A list of strings representing the input formats which may be used to parse the date.  If not specified, the `DATE_INPUT_FORMATS` setting will be used, which defaults to `['iso-8601']`.
@@ -336,7 +336,7 @@ A time representation.
 
 Corresponds to `django.db.models.fields.TimeField`
 
-**Signature:** `TimeField(format=None, input_formats=None)`
+**Signature:** `TimeField(format=api_settings.TIME_FORMAT, input_formats=None)`
 
 * `format` - A string representing the output format.  If not specified, this defaults to the same value as the `TIME_FORMAT` settings key, which will be `'iso-8601'` unless set. Setting to a format string indicates that `to_representation` return values should be coerced to string output. Format strings are described below. Setting this value to `None` indicates that Python `time` objects should be returned by `to_representation`. In this case the time encoding will be determined by the renderer.
 * `input_formats` - A list of strings representing the input formats which may be used to parse the date.  If not specified, the `TIME_INPUT_FORMATS` setting will be used, which defaults to `['iso-8601']`.