The Canon PowerShot SD940 IS is another very small, very lightweight 12-megapixel camera. It drops the SD780's optical viewfinder, and in its place gets a larger 2.7-inch LCD in back, and a wide-angle 28mm-equivalent lens with a 4x zoom in front. Aside from a couple minor interface tweaks, everything else basically stays the same; this includes the earlier model's mixed performance and tendency to produce purple fringing. However, neither is extreme for this class of camera, and all things considered, the SD940 IS is one of the best ultracompacts available.
The SD940 has a revamped menu and help system with hints and tips for choosing the appropriate settings or simply telling you what the shooting mode you're in is going to do. For example, if you don't know what the camera's Servo AF does, just select it in the settings menu and at the bottom of the screen it'll tell you that it continues to adjust focus while pressing the shutter button halfway down. Help systems certainly aren't uncommon, but Canon executed this well considering the limited screen space.
But the SD940 is limited to three shooting modes. A small switch on back moves you between Canon's improved automatic scene recognition called Smart Auto, Program/Scene, and Movie. The Smart Auto mode is very reliable and since it's now picking from 22 different scenes (up from 18 on the SD780), the bases are well covered. In Program you can control things such as ISO, white balance, light metering, and autofocus type or you can switch to one of 17 scene shooting options including common ones like Portrait and Indoors or specialty choices such as Long Shutter and Color Accent. The Movie mode is capable of recording at an HD-quality resolution of 720p. (For quickly connecting to an HDTV, there's a mini HDMI output behind a small door where your thumb naturally rests while shooting.) But sadly, the 4x optical zoom doesn't function while recording.