The IXUS 105's overall performance is pretty impressive. It starts up extremely quickly, and is ready to take a picture in well under two seconds. The shot-to-shot time in single shot mode is a little slow at 2.8 seconds, but there's none of the annoying response delay found with many other cheaper cameras. In continuous shooting mode it can maintain a rate of one shot every 1.6 seconds, which is again a bit on the slow side, but is at least consistent.
The autofocus system is also a tiny bit on the slow side, although only compared to higher-spec IXUS models, but it is accurate and reliable in most normal lighting conditions. Unfortunately its low light focusing is not nearly as reliable, and the AF assist lamp is quite feeble with an effective range of only about 1.5 metres. The flash is also a bit weak, leaving some dark corners in a four-metre-square room, but it does work well at closer range. Battery life is excellent, with the hefty 1000mAh lithium-ion rechargable giving a claimed 240 shots per charge.
As usual with Canon the 105's saving grace is its overall picture quality, which is excellent and certainly a match for anything else in its price range. The lens has good corner-to-corner sharpness and produces very little wide angle distortion, although there is some noticeable chromatic aberration towards the corners of the frame. Colour reproduction is bright and well saturated with good detail even in brighter colour areas, and dynamic range is surprisingly good for a tiny 1/2.3 inch 12MP sensor.
Noise control too is excellent, with very good image quality at 400 ISO and usable images even at the 1600 ISO maximum setting. Colour reproduction remains consistent at all ISO settings.
Although it is near the bottom of Canon's range and is a bit limited in terms of style, features and performance, the IXUS 105 is a good medium-spec ultra-compact camera for a reasonable price. It may lack the sparkle of the more expensive models, but it more than makes up for it in overall image quality.