The K800i had the K790's same outstanding picture quality with bright colors, distinct object outlines, and sharp effects. The flash can be too strong at times, so use it at your discretion. Video quality was satisfactory overall, but it was also a bit grainy, and quick movements were blurry. Clips meant for multimedia messages are capped at two minutes; otherwise length is limited by the available memory. When you're finished with your photos, you can save them to the phone's 64MB of shared internal memory (we suggest getting a Memory Stick for more storage). You can also send your snaps wirelessly via Bluetooth, e-mail, or a multimedia message; upload them quickly to an online blog; or transfer them to a computer via a USB cable. For creative types, the phone has photo- and video-editing applications including a fun FaceWarp application for playing with your favorite headshots.
The K800i's music player lets you organize music by artist, track name, or playlist and choose from settings that include album/song shuffle and loop, stereo widening, and an equalizer. Music stops automatically when you get a call, you can minimize the player's interface, and an airplane mode lets you listen to your tunes in flight with the cell phone turned off. There are stereo speakers on the back and the phone supports a Bluetooth profile. Music capacity is limited by the available memory, so again buying a Memory Stick Micro is a good idea. To get music on the phone, you can use an included USB cable or send tunes via Bluetooth or the infrared port. You also get the Sony Ericsson FM radio with 20 presets, though you must use it with a headset, which acts as an antenna.
You can personalize the K800i with a variety of themes, wallpaper, and screensavers. As always, you can purchase more options and ring tones from Sony Ericsson via the WAP 2.0 wireless Web browser. Alternatively, the phone comes with a Music DJ application for composing your own ring tones. Gamers can enjoy three Java (J2ME) titles: FotoQuest Fishing, Mini Golf: Castle, and Tennis Multiplay, with additional titles available for purchase. Like with the Sony Ericsson W600i, some games are played in landscape mode while using the special gameplay keys above the display.
We tested the triband (GSM 900/1800/1900; UMTS 2100) Sony Ericsson K800i world phone in San Francisco using Cingular service. Call quality was comparable to that of the K790a, which is to say it was very good with nice clarity, little static, and no interference from other electronic devices. Likewise, volume could be a bit louder on our end, but it should be quite serviceable for most users. Calls faded out a bit in buildings, but that's to be expected since the phone isn't operating on the GSM 850 band. On their end, callers had similar experiences. They could tell we were using a cell phone, but they had few problems hearing or understanding us. Speakerphone quality was good as well. Just take note that on the K800i, the main speaker faces the back of the phone as well.
The K800i has a rated talk time of seven hours and a promised standby time of 14.5 days. We managed to get an impressive six hours and 45 minutes of talk time in our tests. According to FCC radiation tests the K800i has a digital SAR rating of 0.58 watts per kilogram.