The slideshow is where you can view your photos full-screen, and zoom in to view them at full scale.
The normal way of sending photos to the slideshow is to select them in the grid, and then either double-tap one photo or tap the Slideshow button on the tab bar. All selected photos will be passed to the slideshow. As a convenience feature, if you tap the slideshow button without any photos selected, all photos are sent in.
Photos may also be sent to the slideshow automatically as they are received, if you have the setting for this switched on.
The main view controls in the slideshow are what you might expect; you can drag the photo around and pinch to zoom. There are many more controls available though.
Tap and hold to show a box which lets you enter captions and comments, if these features are enabled in Settings.
Double-tap to zoom all the way in or out.
Pinch to zoom manually.
Swipe left or right to move back or forward by one photo, if more than one was selected.
Several of the controls on the tab-bar are the same as those on the tab-bar in the Grid. You can use them to both view and change the star rating, flag and label for the currently selected photo using the controls on the left of the tab-bar.
The next controls are for the slideshow itself. If you have more than one photo in the slideshow, you can use the “previous” and “next” controls to move forwards and backwards through the selected photos. These are exactly the same as swiping left and right. The “play” control sets the slideshow into play mode, where all selected photos are shown one after another. The delay between photos can be changed in the Settings page. You can stop the slideshow at any point by using the “pause” control in the toolbar, which will replace the “play” button, or by tapping and holding anywhere on the screen.
Tap pause to stop the slideshow.
Tap and hold anywhere on the screen when in slideshow mode to stop the slideshow.
To the right of the toolbar are three controls which set what elements are displayed on screen. To take the simplest control first, the padlock button locks the toolbar into place. Normally, when the slideshow is playing, the toolbar and tab-bar will automatically be hidden. Locking the toolbar prevents this. This is useful if you want to use the metadata controls during a slideshow.
The Information Overlay
The other control on the right, the “i” button, lets you show some of the photo’s metadata as an overlay. This overlay can be set to show any of the metadata from the currently displayed photo. You can drag the overlay around the screen to position it where you want it, and you can also resize the overlay by dragging the edges instead of the center.
To set what is displayed in the overlay, make sure it is displayed and then tap and hold on it. A dialog will appear which will let you choose three lines of information to display. Each line can be made up of more than one piece of information, so for example you can choose to show the shutter speed and aperture on line one, the camera make on line two and the lens data on line three.