Started updating documentation

docs/source/camera.rst

@@ -1,9 +1,35 @@
 Camera Class
-=======================================================
+============
 
 .. toctree::
    :maxdepth: 2
 
    picamera.rst
    basecamera.rst
-   capture.rst
+   capture.rst
+
+Capturing from a camera object
+------------------------------
+
+In the cases of both a Raspberry Pi Streaming Camera, and a Mock Camera (attached if no real camera can be found), the camera's ``capture`` method takes as it's first positional argument either a string describing a file path to save to, or any Python file-like object.
+
+The :class:`openflexure_microscope.camera.capture.CaptureObject` class works by providing a file path string, but adds additional functionality around storing and retreiving EXIF metadata in compatible files.
+
+If, for your application, you do not require this functionality, you can pass a simple string or file-like object. For example, to take an image that will be stored in-memory, processed rapidly, and then discarded, you could use a BytesIO stream:
+
+.. code-block:: python
+
+    import io
+    from PIL import Image
+    ...
+
+    with microscope.camera.lock, io.BytesIO() as stream:
+
+        microscope.camera.capture(
+            stream,
+            use_video_port=True,
+            bayer=False,
+        )
+
+        stream.seek(0)
+        image = Image.open(stream)