When the moment comes to take the perfect picture of a snowy mountaintop, Fourth of July fireworks or soccer goal in midkick, most people forget about these features or don’t know how to use them. And while many digital cameras can now detect faces and make sure they are in focus, they can’t tell whether that face is smiling or not. The results aren’t bad, but they could be much better.

Sony’s Cyber-shot DSC-W170 uses Smile Shutter Mode to snap pictures when a subject smiles.

This week, I tested three new digital cameras that claim to do the thinking for you. Some digitally analyze the scene you’re about to capture, automatically choosing the setting that would take the best picture. Others can detect when a subject is smiling so as to automatically know when to snap the photo. One camera even attempts to digitally alter frowning faces into smiles, with amusing results.

I tried out Sony’s $300 Cyber-shot DSC-W170, Kodak’s $250 EasyShare Z1085 IS and Olympus’s $200 FE-340. Only the Sony (SNE) includes all three of the aforementioned features; the Kodak (EK) has scene detection, and the Olympus (OCPNF.PK) camera has built-in smile detection. I found the automatic scene detection offered in the Sony and Kodak cameras to be the most useful feature for everyday photos. It improved my photos and didn’t require any extra adjustments. I handed the cameras to other people to take pictures, without having to change any settings.

The automatic smile detection offered in the Sony and Olympus cameras was fun to use and could be especially helpful for families whose young kids never seem to smile at the right moment. But it didn’t work consistently and had trouble detecting my bearded boss’s smile and even that of a beard-free colleague.

I found Sony’s frown-fixing tool, which is called Happy Face Retouch, to be rather unusual. It took already captured images of my friends’ faces and turned their frowns or ambivalent looks into smiles, but didn’t adjust the subjects’ eyes. Though this was good for laughs, the eerie-looking grins pasted on faces reminded me of painted-on clowns’ mouths. And some attempts to retouch a face couldn’t detect the face to alter it. But a handful of the Happy Face Retouches looked somewhat natural.

Similar Specs

These cameras boast many similar specifications. All three use 5x optical zoom lenses, and the Sony Cyber-shot DSC-W170 and Kodak EasyShare Z1085 IS each have 10.1 and 10 megapixel image sensors while the least expensive Olympus FE-340 has 8 megapixels. The Sony and Olympus both have generous 2.7-inch viewing screens and almost identically sleek builds, though the Sony is the only one of these three cameras to have an optical viewfinder.

The Kodak’s viewing screen is slightly smaller than the other two digital cameras, measuring 2.5 inches, but its build isn’t nearly as compact as the others. It reminded me more of small, high-end SLR camera, with its comfortably large hand grip, a settings knob on the top edge of the camera, and a protruding zoom lens.

Sony’s Happy Face Retouch feature digitally changes facial expressions into smiles, but all it did was make me look unnatural and awkward.

Kodak’s EasyShare Z1085 IS takes Secure Digital (SD) memory cards, which are more common than the Memory Stick and xD cards that work in the Sony and Olympus cameras, respectively.

The Kodak and Sony digital cameras have different names for their automatic scene-detection features. By default, the Kodak camera works in Smart Capture Mode, which includes intelligent scene detection, capture control and image processing. I focused on the camera’s scene detection, which automatically determines whether the photo should be taken in Macro, Text (for shots of text in a book, for example), Face, Landscape or Night settings.

Icon on the Screen

I snapped pictures around Washington, D.C., noting a tiny icon on the camera’s screen that indicated which of the five scene modes was being used to capture the photo. A flower icon indicating Macro appeared on my screen when I stooped to get a close-up shot of a tulip, and an icon of a dark sky and stars showed on the screen when I took photos at night. The camera’s flash, focus and exposure changed according to the type of photo.

The Sony camera uses what it calls Intelligent Scene Recognition to decide which settings should go along with certain photos. Like the Kodak, icons on the Sony’s screen indicated the scene settings that were automatically deemed appropriate, including Backlight, Backlight Portrait, Twilight, Twilight Portrait and Twilight Using a Tripod.

The Sony’s Intelligent Scene Recognition isn’t on by default like Kodak’s feature. Instead, it must be turned on from within a menu, but once on, it stays on until you turn it off. ISR can be used in either Auto or Advanced mode; Auto takes a single photo with automatically determined settings, while Advanced takes two shots — one with manual settings you can choose and another shot immediately following the first with automatic settings according to what the camera thinks is best.

I experienced surprising results with the Sony Cyber-shot DSC-W170 and Olympus FE-340 while testing their automatic smile-detecting functions. My friends thought I was joking when I told them the camera would take their picture only if they were smiling. When the flash went off multiple times as they kept smiling, they were intrigued by this feature.

Sony’s version, which it calls Smile Shutter Mode, is easy to switch into by turning a dial on the camera to a smiley face. Once this setting is chosen and the camera’s shutter button is pressed, the Cyber-shot will search for smiles in its subjects, and will take photos whenever it detects a smile. Settings within this mode can be set to specifically detect an adult’s smile or a child’s smile, and the degree of smile can be set to low, medium or high; I kept things simple by leaving the smile detector on default settings.

Capturing Smiles

Olympus calls this feature Smile Shot, capturing three rapid shots in a row to make sure everyone’s smiling. The idea of taking three shots would be extra helpful with an indecisive baby, but most of my friends were able to hold their smiles, which produced three almost exactly identical shots each time someone smiled. Smile Shot is harder to get to in a pinch compared with the Sony: it’s buried in a list of 13 settings on the Olympus when the camera is set in Scene mode.

The Olympus seemed to be a bit slower than the Sony when it came to detecting smiles, but both had trouble with bearded men and even some folks without beards. And people felt silly standing around with a smile on their faces waiting for the camera to finally work. Closed-mouth, no-teeth smiles were harder for these cameras to detect, but not impossible. In group situations, the Olympus camera will focus on whoever’s face appears largest, which could mean the person closest to the camera, while the Sony takes a picture whenever anyone in the group smiles.

Putting a Happy Face On

If someone isn’t smiling, Sony’s Happy Face Retouch tool can come in handy, but don’t count on liking the results. In a group shot of five friends, two people who weren’t smiling put a bit of a damper on the whole shot. I used Happy Face Retouch, but it picked up on only one of the nonsmiling faces, turning a confused look into a smile that looked passable. But other results weren’t usable. A serious-looking shot of me deliberately not smiling looked freakishly unnatural after the touch-up, mostly because the rest of my face didn’t join the smile. I looked more like someone who had received too many Botox treatments.

Sony says that, in group shots, it can detect and change up to eight faces, but in my tests it usually changed only one. This retouching tool is also difficult to find: It took me 16 button presses to change each image into a smile — or what Sony calls a smile. A few times, Happy Face Retouch couldn’t identify a face in the photo, even when just one person stood in the frame.

These digital cameras took good photos, overall, and are fun to use because they take pressure off the photographer. I found the automatic scene-detection tools of the Kodak and Sony to be the most realistic and useful offerings, and I’m sure it won’t be long before automatic scene detection becomes as commonplace as an automatic flash.

The chart below compares features of the three cameras described. Click on it to make it larger.

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Digital Cameras

Megapixels: This term describes the highest resolution photo a camera can take. Often mistaken as the most important factor in a digital camera, a high megapixel count — such as 10MP or more — isn’t necessary for the average user unless he or she plans on heavily editing or enlarging photos. Most new digicams offer between five and eight megapixels, which is usually more than enough.

Optical or Digital Zoom: Optical zoom, determined by the physical movement of a lens, matters much more than digital zoom, which digitally alters an image using the camera’s internal computer. Camera companies still try to confuse potential buyers by listing a camera’s total zoom, or the optical and digital zooms multiplied together. Ignore total zoom numbers and instead focus on optical, which now averages around 5x for many new cameras.

Image Stabilization: When generously sized LCD viewing screens started replacing optical viewfinders, they also forced users to hold their cameras at arm’s length, making for plenty of blurry photographs. To remedy this, camera manufacturers have added image stabilization, tools once found only in high-end SLR models. Optical (also called “mechanical”) and digital image stabilization correct for unsteady hands and moving subjects, respectively. Cameras with both types advertise dual image stabilization, which corrects for both situations and costs more.

Mobile Devices

HSDPA and EVDO: HSDPA, or High Speed Downlink Packet Access, is the name for AT&T’s 3G, or third generation, mobile network that operates at roughly the speed of a slower DSL in a home. HSDPA is available in most major metropolitan areas and is seen as the competitor to Verizon and Sprint’s EVDO (Evolution Data Only) networks, though the popular iPhone runs on AT&T’s network using Wi-Fi and EDGE technology rather than HSDPA.

Multi-Touch Technology: Most popularly found on Apple’s iPhone and iPod touch, multi-touch is starting to show up in other products, such as in Microsoft’s Surface, a coffee-table-like computer. Rather than just responding to on-screen touches, this technology enables moving, resizing and zooming pictures and Web pages using one or more fingers simultaneously. Look for many more devices — mobile and otherwise — to incorporate multi-touch in the future.

GPS: Global Positioning Systems are most often found in cars — either built-in or on portable devices from companies like Garmin and TomTom. These gadgets use satellite technology to determine geographic location, and high-end models even display Web content like news and weather along with directions. GPS integration in mobile devices can be used to plot routes in cars, can help users find nearby businesses while on the go and can link friends by showing one where the other is located and what they’re doing.

Digital Music

DRM: Digital rights management is a set of standards that protect the intellectual property rights of online content like music and videos, preventing it from being illegally distributed across the Web. In the past year, Vivendi’s Universal Music Group, Apple and (most recently) Sony BMG said they will start selling DRM-free versions of songs, often for a higher price. In Apple’s iTunes store, these files are called “iTunes Plus” and aren’t restricted like other iTunes content.

MP3: MP3 files are open, without any DRM restrictions. Files that you rip (copy) from your own CDs are usually converted into MP3s, though iTunes users can automatically rip tracks into that program’s special format, called AAC. MP3 files can be uploaded to social-networking sites for sharing with friends and online communities.

These file types are protected by rights that tie them to specific players. Generally, AAC files make up the majority of tracks sold on Apple’s iTunes store and play only on Apple’s iPods; WMA files are Microsoft’s version of proprietary files.

Wi-Fi

The popularity of Wireless Fidelity, or Wi-Fi, brings this technology to more and more portable devices like the iPod Touch and Microsoft Zune and gives companies good reason to incorporate Wi-Fi receivers in new computers — laptops and desktops alike. While available in many flavors, different letters like b, g, a and n stand behind Wi-Fi’s more technical name, 802.11, to help discern one version from another according to characteristics like speed and compatibility. The latest version, “n,” offers the greatest range and speed, and “n” devices are usually compatible with earlier versions.

Televisions

HDTV: High-definition television has now become the standard, capable of displaying vastly better pictures, provided the source is also HD. Today’s more popular flat panel HD televisions are LCDs, or liquid crystal displays, though plasmas still hold their own. Recording HD content can’t be done with a regular digital video recorder; instead, a special HD recorder is required to capture this higher quality content.

480p vs. 1080i vs. 720p vs. 1080p: These numbers refer to the resolution, or sharpness, of a digital display, while “p” stands for progressive and “i” stands for interlaced. A resolution of 480p, known as EDTV or Enhanced Definition TV, is found most often in low-end plasmas or LCD screens. A TV with a resolution of 1080p is currently considered the Holy Grail, and costs the most. But 1080p pictures usually can’t be distinguished from less expensive 1080i or 720p pictures by average viewers at the typical distances from which most folks watch TV.

Blu-ray vs. HD DVD: Blu-ray and HD DVD are incompatible high-definition disc formats that continue to fight a seemingly endless battle to replace the DVD. The Blu-ray camp is led by Sony and the HD DVD camp is led by Toshiba. The two formats aren’t so different, technically speaking, but their very existence is confusing to consumers. The recent decision made by Time Warner’s Warner Bros. to use Blu-ray gives Sony’s side a boost, and now Viacom’s Paramount is rumored to be switching to Blu-ray from HD DVD. Dual-format players from Samsung and LG offer some solace.

Email: mossbergsolution@wsj.com