If I just create a iPad version can it be used for the iPhone as well?
The end result of doing that would be the iphone will just scale ipad renditon accodingly and leave those black bars on either side when viewd on the iPhone. Is that correct?
Or is it mandatory to create a iphone specific version in Indesign as well as a iPad version?
No, you need to create folios with a 3:2 aspect ratio (such as 480x320) for the iPhone. The 4:3 (1024x768) folios you create for the iPad don't show up on the iPhone viewer.
Europe, Middle East and Africa