Kodak DCS 500 Series User Manual page 210

You will not be able to record sounds and the Microphone icon will not be displayed in the
Back LCD panel under the following circumstances:
No image in the current folder
You are using the DCS Host software in Test Shot mode. (Refer to the KODAK
PROFESSIONAL DCS Host Software User's manual on the CD included with
your camera.)
11-10
A Sound icon is displayed at the
right of the menu bar, indicating
that the selected image has an
associated sound file.