If you feel you need to quickly boost your sensitivity to raise the shutter speed, Canon's Auto ISO Shift will boost the ISO with a single button press but caps the sensitivity at ISO 800 in an attempt to keep ISO noise at bay. To help with portraits, Canon includes a rather effective face-detection mode. Unlike some companies, which give face detection a dedicated button, Canon places it at the top of its menu.
In our lab's performance tests, the TX1 turned in mediocre results. The camera's built-in lens cover and extending lens barrel must slow down the start-up a bit, because the TX1 took 1.82 seconds to start up and capture its first JPEG. After that, it took 1.99 seconds between JPEGs with the flash turned off, and 3.3 seconds between JPEGs with the flash turned on. We were impressed with the shutter lag though, which measured 0.55 second in our high contrast test, which mimics bright shooting conditions, and 1.2 seconds in our low-contrast test, which mimics dim shooting conditions. Regardless of image size, the TX1 captured 1.04 frames per second in our continuous shooting tests.
Image quality wasn't what we've come to expect from Canon. Overall, video turned out better than stills though. The footage we shot wasn't perfect, but was sharper than footage from the Sanyo HD2, and while the TX1's footage did have its fair share of compression artifacts, it certainly had fewer than the HD2, especially on edges of objects, and showed a significantly wider dynamic range than the Sanyo. The reason for Canon's edge in video quality most likely has to do with the fact that the TX1 uses Motion JPEG compression instead of MPEG-4. Of course, Motion JPEG also consumes more memory than MPEG-4. A 1-minute 720p clip we made took up about 267MB on our SD memory card. Both the Canon and Sanyo lagged a bit on focus compared with a dedicated camcorder, though again, the Canon edged out the Sanyo. Overall, if you're looking to capture really good HD footage, you'll need to step up to a dedicated HD camcorder, such as the Canon HV20 or the Sony Handycam HDR-HC7.
Still images showed more ISO noise and image artifacts than we're used to with Canon's digital still cameras. We also saw other image artifacts, which turned some curved lines and angled lines jaggy. Colors looked accurate overall, and we saw a decent amount of finer detail, but the images weren't as tack sharp as many of the company's cameras from recent years. Noise doesn't become very significant until ISO 400, but we saw some on our monitors with the sensitivity as low as ISO 100, though you most likely won't notice it in prints. At ISO 400, noise becomes obvious on monitors, starts to show up in prints, and begins to chew up some of the finer detail, though dynamic range remains largely intact. At ISO 800, noise becomes a heavy blanket of fine snowy specks, obscuring lots of finer detail and eating up more dynamic range. At ISO 1,600, most fine detail is destroyed by the vast snowy blizzard of tiny speckles, and dynamic range is crunched to the point of obscuring most shadow detail. We suggest staying below ISO 800 when possible.
If you absolutely have to have a combo still camera/720p HD camcorder, the Canon PowerShot TX1 is probably the best bang for the buck. Its two serious competitors, the Sanyo Xacti HD2 and Panasonic SDR-S150 both cost significantly more, and in the case of the Sanyo, you get lower quality video and stills but a more comfortable-to-use design. Ultimately, you're still better off buying separate video and still cameras, though maybe someday combo devices like this will reach a point when they'll make sense for the casual vacation shooter. Despite all that, we do have to commend Canon for having the guts to push ahead with an experimental product like the TX1.