Shaped like a Dove bar, the Cyber Shot DSC-S40 is thicker than many other point-and-shoot models. The depth of the case allows a secure grip, which is especially important when you need to concentrate on your next photo. Measuring 3.9 by 2.0 by 1.3 inches, it's small enough to fit into a pants or coat pocket. And at 6.5 ounces with a Memory Stick and two AA batteries installed, it won't weigh you down.
The 1.5-inch LCD seems stingy when you realize there's ample room on the back of the camera for a 2-inch screen. This was obviously a marketing decision rather than a technical limitation; the main incentive for moving up to the Cyber Shot DSC-S60 is its 2-inch screen. Though small, the screen is detailed enough to let you judge the quality of potential shots. The onscreen menus are bright and clear, even in direct sunlight.
The Cyber Shot DSC-S40 balances well in either one or both hands. Its back-mounted controls are accessible with your thumb, though the metal hook for the wrist strap can get in the way when you stretch your hand to reach the mode switch. Overall, the buttons are sturdy and responsive, which isn't always the case with inexpensive cameras.
In addition to a fully automatic option, Sony provides seven shooting modes that are identical to those offered by the Cyber Shot DSC-S90. They include Snow, Candle, Beach, Twilight Portrait, Landscape, Twilight, and Soft Snap. You can toggle between multipoint and center-spot autofocus, which gives you some flexibility in composing shots. You can also change the white balance to match the type of light source, manually select the ISO sensitivity (80, 100, 200, or 400), and choose the image-compression rate (Fine or Standard).
This model offers the same continuous-shooting modes as the Cyber Shot DSC-S90. Its Burst mode grabs four high-resolution shots in 2.6 seconds. The Multi-Burst mode grabs 16 shots in 0.5 second. Multi-Burst shots play back as individual photos while in the camera but are merged into a single multiwindowed photo when saved to a computer.
One problem with any low-end digital camera is the starkness of the built-in flash. Some expensive cameras have an accessory shoe for mounting an external flash, which you can pivot to bounce light off a ceiling or a wall. That diffuses the light and gives subjects a less harsh appearance. Sony offers the $100 HVL-FSL1B Cyber Shot Slave Flash as a second light source for the DSC-S40. We weren't able to try it, but it or a similar third-party product could improve your flash photos.
On most of our tests, the Cyber Shot DSC-S40 performed as fast as or faster than the more expensive DSC-S90. The Burst and Multi-Burst timings were identical to the Cyber Shot DSC-S90's at 1.54fps and 32fps, respectively. The Cyber Shot DSC-S40's wake-up-to-first-shot time of 2.22 seconds was very good for a point-and-shoot camera, beating that of the Cyber Shot DSC-S90 by 0.45 second. Shutter lag was a quick 0.19 second in bright light and 0.26 second in dim light, and the average shot-to-shot time without the flash was just 1.11 seconds. All three times were marginally better than those of the Cyber Shot DSC-S90. One place the extra money spent on a Cyber Shot DSC-S90 would pay off is in the shot-to-shot times with the flash. The Cyber Shot DSC-S90 snapped back after 2.21 seconds, while at 3.51 seconds, the Cyber Shot DSC-S40 took much longer to reset itself. The battery life will vary depending on the type of AA batteries you use (two are required). According to Sony, you should be able to shoot 110 photos with alkaline batteries or 480 photos with nickel-metal-hydride batteries.
Our test shots from the Cyber Shot DSC-S40 were similar in quality to the ones we took with the Cyber Shot DSC-S90. Like its higher-priced sibling, the Cyber Shot DSC-S40 produced photos with a slight softness along with accurate and distinct colors. We did find the Cyber Shot DSC-S40's colors slightly less saturated than those of the Cyber Shot DSC-S90. With the Cyber Shot DSC-S90, rich colors and a wide dynamic range helped compensate for slight image softness. With the Cyber Shot DSC-S40, colors were a little less intense and dynamic range a little more constrained. Given the relative prices of the cameras, these subtle differences weren't out of line.
Exposure accuracy varied more than it should have, causing some overexposed and underexposed photos. Most of the time, the exposure was right where it should be, but when it was off, it could be by a considerable margin. We captured many excellent photos with this camera; it's just that a slightly higher percentage than we expected were off the mark technically.