Use the Field (View) element to return a formatted field value for display within a view, and use the Column (View) element to return the raw data value of the field.
To create a custom field definition as a pluggable Feature that is based on a default Windows SharePoint Services field type and that can be reused across sites and lists, use the Field (Field) element to define a custom site column. To create a custom field definition for a list definition based on a default field type, use the Field (List - Definition) element within a Schema.xml file. To create a custom field type that implements a custom class for special data validation and field rendering, use the Field (Field Types) element.