Like the K790a, the K800i sports a simple candy bar form factor that's roughly rectangular in shape but still sleek and stylish. What's more, the black-and-gray color scheme accurately reflects the high-tech features inside. It's far from compact (4.1 by 1.9 by 0.9 inches; 4.1 ounces) but with its solid construction and comfortable feeling in the hands, it's a worthy trade-off.
The K800i has the K790a's same brilliant 262,144-color display that measures two inches diagonally (240x320 pixels). Below the display is the navigation array, which is similar as well. The five-way joystick doubles as a shortcut to four user-defined functions, while the two soft keys open the recent-calls list and the main menu when the phone is in standby mode. There are also dedicated Back and Clear buttons, a key that launches the Web browser, and a nifty control that opens a submenu of user-defined shortcuts and a list of upcoming calendar events. Overall the navigation controls were tactile and easy to use, but they are somewhat squashed together. The backlit keypad buttons were a nice change, however, from previous Sony Ericssons. Rectangular in shape, they are large enough for most hands and are raised just above the surface.
A music player button and the Memory Stick Micro slot sit on the left spine, while the right spine holds a volume rocker and a camera shutter control. The camera lens and self-portrait mirror sit on the back of the handset behind a sliding cover. Above is the large, high-quality flash, while a small speaker is next to the camera lens.
The phone book holds a respectable 1,000 contacts with room in each entry for five phone numbers, Web and e-mail addresses, a work title and company name, work and home street addresses, a birth date, and notes (the SIM card holds an additional 250 names). You can organize contacts into groups and pair them with photos for caller ID. You can pair contacts with one of 16 72-chord polyphonic and MP3 tones. Other essential offerings include a vibrate mode, text and multimedia messaging, an alarm clock, a calendar, a task list, a timer, a stopwatch, a calculator, a notepad, and a voice memo recorder (space is limited by the available memory).
The K7800i also comes with a wealth of business-friendly features. You'll find full Bluetooth for connecting to a wireless headset or sending files or your electronics business card to another Bluetooth device. And like with many other Sony Ericssons, you can use the phone as a modem and use the Bluetooth feature as a remote control to connect with other Bluetooth devices. Other high-end goodies include a speakerphone, an RSS news reader, an infrared port, PC syncing for contacts and other files, USB cable support, e-mail, voice dialing, and a code memo for storing passwords and other secure information. And because the phone supports UMTS networks, you can watch streaming video.
Like the K790a, the 3.2-megapixel K800i Cyber Shot is one of the most advanced camera phones we've reviewed. Camera features were the same on both phones. You can take pictures in four resolutions, from VGA up to the full 3 meagpixels, and choose from two image quality choices. Other notable offerings include a panorama mode, red-eye reduction, spot metering, a macro setting, and image stabilization (see the K790a review for a full list of the camera features). The camcorder, which is also similar, takes MPEG-4 clips with sound in one resolution (176x144). And here again the remarkable Xenon flooded our photos and videos with light even in dim situations.
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.