UIModalTransitionStyle is used to specify how the modal form transitions into view. For example,it can come in vertically,flip horizontal,or do a partial curl.

UIModalPresentationStyle is used to specified whether you want the modal form to be full screen (basically what iPhone uses) or otherwise (therefore only makes sense for iPad) as a page sheet (full height,width is the size of the porTrait mode screen width),a form sheet (partial width and partial height) or current context (i.e. what the parent container uses).