Rear of camera controls

The rear of the Optio 550 is fairly unsurprising in its design, a large space on the right side for your thumb, a single lever type zoom controller, a four way controller and six other buttons.

Buttons functions in shooting (record) mode

Icon
  		Mode

Flash mode

• Auto Flash
• Flash Off
• Flash On (fill-in)
• Auto Flash with red-eye reduction
• Flash On with red-eye reduction

Drive mode

• Single shot
• Self-timer
• Remote control (3 sec self-timer)
• Remote control
• Continuous
• Interval shooting (time-lapse)
• Superimposed

Focus mode

• Auto focus (wide area)
• Macro auto focus
• Super-Macro auto focus
• Infinity lock (landscape)
• Manual focus (magnifies center of frame while focusing)
• Select AF area (any one of five areas)

Zoom wide

Press the zoom lever in this direction to zoom towards wide angle (37.5 mm equiv.), there are eleven steps from telephoto to wide angle.

Zoom telephoto

Press the zoom lever in this direction to zoom towards telephoto (187.5 mm equiv.)

Enter play mode

Switches to the camera's play mode, from here you can browse, erase, protect and perform other functions on previously taken images. The camera by default displays the last image taken or the last image on the card. Use the 4-way controller's left or right buttons to browse. The Optio 550 is a shooting priority camera which means you can always return to shooting mode by simply half-pressing the shutter release (or press Play again).

4-way direction controller

The up and down arrows have no function in shooting mode, however left and right arrows are used to adjust exposure compensation (if allowed in current shooting mode).
OK

OK / Confirm

Has no function in shooting mode other than in menus and to confirm setting changes.
MENU/Fn

Menu / Function

A single press of the Menu button enters or leaves the camera menu. You can program certain functions which can be activated when holding this button and pressing any of the four direction buttons. For example you could program Menu + Left Arrow to change sensitivity, Menu + Right Arrow to change white balance. This is a VERY useful feature, Kudos Pentax.
DISPLAY

Display

Switches the current LCD monitor display mode:

• Default display (brief settings, exposure mode, date)
• Histogram display (detailed settings, overlaid live histogram)
• Grid display (brief settings, thirds grid overlaid)
• AF brackets (just AF brackets)
• LCD monitor off

Buttons functions in play mode

Icon
  		Mode

Protect

Pressing the protect button displays an option to Protect or Unprotect the current image, it seems to me that it would have been easier to simply make this a toggle switch for protection. Press Protect twice to Protect or Unprotect all images. Note that when an image is protected its 'read-only' flag on the flash card filesystem is set, this can guard against accidental deletion from the camera but not from a full card format.

DPOF

Displays the DPOF (Digital Print Order Format) option for the current image, select the number of copies you want and if you want the date overlaid. Press the DPOF button twice to set DPOF options for all images. DPOF works by writing a small 'print order' file onto the flash card which compatible printers and photo finishing kiosks recognize.

Delete

Pressing the erase button displays an Delete / Cancel option, press Erase twice to have the option to erase all images on the card. If the image has an attached sound annotation you can choose to remove that from the image ('Sound Delete').

Thumbnail index (nine image display)

Press this button to switch to a 3x3 thumbnail index, navigate through the images using the 4-way controller and press OK (or this button again) to return to a single image view.

Magnify

Magnifies the current image up to 8x zoom, once magnified you can pan around the image using the 4-way controller. Press OK to return to a single image view. Available magnification levels: 1.1x, 1.2x, 1.3x, 1.4x, 1.5x, 1.6x, 1.7x, 1.8x, 1.9x, 2.0x, 2.2x, 2.4x, 2.6x, 2.8x, 3.0x, 3.3x, 3.5x, 3.8x, 4.0x, 4.5x, 5.0x, 5.5x, 6.0x, 6.5x, 7.0x, 7.5x, 8.0x.

4-way direction controller

In single image view press left or right to browse through images, in thumbnail index view you can use all four arrows to move around the images, in magnified view you can use the arrows to pan around the magnified image.
OK

OK / Confirm

In single image view press OK to record a voice annotation of up to 30 seconds, otherwise the OK button is used to return to single image view from either thumbnail index or magnified view modes.
MENU/Fn

Menu / Function

Enters the play menu which provides functions such as image resizing, trimming, slideshow and even setting a photo alarm.
DISPLAY

Display

Switches the current LCD monitor display mode:

• Default display (filename, date and time)
• Histogram display (as above plus exposure info, settings and a histogram overlaid)
• No overlay (just the image, no information)