It's difficult to classify Canon's PowerShot TX1 camera because, functionally, it sits somewhere between a medium-resolution digicam and a camcorder. Combining a 7.1-megapixel imager with a 10x optical zoom lens, the TX1 is larger than Canon's Ixus models but has a similar, stainless steel clad body. But its zoom range and video resolution are closer to Canon's high-definition camcorder products.
Compromises have been made to pack so much into such a small package. The TX1's LCD monitor is, therefore, small – measuring only 1.8-inches. However, it flips out and rotates, just like a camcorder's monitor. You have to flip out the LCD to access the card compartment, which has a somewhat flimsy cover that some users will find tricky to open. The battery card compartment cover is even flimsier but much easier to open.
The lens is also relatively slow for a modern digicam, no doubt as a result of design compromises that have been made to fit such a long zoom into the small camera body. Powering up the TX1 extends the lens roughly 2 cm but thereafter all zoom movements are internal. Wide-angle capabilities are restricted to the equivalent of 39mm to provide 390mm tele focal length.
Ergonomics have been quite seriously compromised. Compared with the elegant Ixus models, the TX1 is awkward to hold and operate, although it packs down into a nice, compact block. The flip-out monitor gets in the way of the on/off button, the control buttons are tiny and the movie button is too easy to press unintentionally. The wrist strap is uncomfortable and poorly positioned and you require two hands to keep the camera steady while shooting – despite the built-in stabiliser.
Unlike most digital cameras, the TX1 comes with a 32MB MMC card – which is woefully inadequate. Canon supplied a 2GB Micro SD card plus SD adapter with the test camera and we feel this is the minimum amount of memory users of this camera would need for shooting video clips. Power consumption is also rather high for a modern long-zoom digicam. Whereas most current models offer at least 250 shots per charge under C.I.P.A. standard testing, the TX1's battery only supports 160 shots. This could be due to the lack of a viewfinder, which forces users to compose shots with the LCD. Or it could be a consequence of the lens-shift optical image stabilisation system. (Cameras with shorter zooms and viewfinders usually have lower power use.)
Functionality
The TX1 has a similar range of controls and functions to a standard Digital Ixus model. The only shooting modes are full auto, 'camera manual' (which allows exposure compensation and white balance adjustments), a scene setting with seven pre-set modes and movie capture. Still shooting modes are set via a rotating dial on the right side of the camera body, while movies are recorded by pressing a button below the zoom lever.
In manual mode, pressing the FUNC/SET button in the centre of the arrow pad lets you select the shooting mode (Manual, Super Macro, Colour Accent, Colour Swap or Stitch Assist), adjust exposure compensation and white balance, use the My Colors settings, choose between 4:3 and 16:9 aspect ratios, set vide frame rates and select image size. JPEG compression levels cannot be adjusted.
Pressing the Menu button when in the exposure compensation settings takes you to the long exposure menu, where you can pre-set exposure times of up to 15 seconds. The FUNC/SET button doubles as a joystick, replacing the standard arrow pad and accessing ISO, flash, drive and focus distance settings. The TX1's DiG!C III image processor also supports the latest Face Detect with Auto Focus, Auto Exposure, Flash Exposure and in camera red-eye correction functions.
The big plusses for the TX1 are its video capabilities, notably the ability to shoot 16:9 aspect ratio movie clips at resolutions up to 1280 x 720 pixels and frame rates of 30 fps. VGA and QVGA resolutions with a 4:3 aspect ratio can also be recorded at the same frame rate and users can select standard or LP modes for the 1280 x 720 pixel and VGA resolutions and between 30 and 60 fps for QVGA clips. Maximum video recording capacity is 4GB (which equates to just under 14 minutes at the standard 1280 x 720 pixel setting). A one hour limit applies to modes with lower resolution and quality. Selecting the LP mode roughly doubles the amount of video you can record on a card – but at a cost to picture quality, especially for moving subjects.
You can also use the TX1 as an audio recorder. Two modes are supported, one allowing you to attach sound bites of up to a minute to selected still pictures and the other simply recording audio. A two hour limit applies to the latter mode.
Video clips recorded with the camera can be played back on regular or widescreen TV sets, with the supplied component cable supporting 1080i (high definition) video on compatible widescreen TVs. The supplied A/V cable must also be connected if you want to hear the stereo audio that is captured with the video clips. You can also grab still frames from the video clips but at the highest resolution setting they don't warrant printing any larger than snapshot size.
Playback facilities for video clips include first frame, last frame, next frame, previous frame, fast forward, fast rewind and slow motion functions for reviewing and editing files via the camera's LCD screen. For still shots, users can playback images singly and enlarge sections of them up to 10x. Sets of nine shots can be displayed in index format and slideshows can be played with fade-in/out transitions. The My Camera menu allows users to select from a number of start-up images and sounds or upload one of their own pictures for use as a start-up image.
Performance
Pictures taken with the test camera were generally sharp and colourful, although we noticed a slight 'warm' bias in many shots and saturation was slightly elevated. Exposures in outdoor conditions tended to favour shadows, so highlight details were often lost unless -0.3EV of compensation was applied. Imatest showed resolution to be slightly below expectations and revealed noticeable edge softening. Resolution at high ISO settings also declined – although less than we expected.
Imatest also showed colour accuracy to be lower than the Ixus cameras we've tested, with slight shifts in reds, yellows and greens and increased saturation in blues. The test camera's lens showed severe chromatic aberration in our Imatest evaluations and outdoor shots taken in bright conditions revealed noticeable coloured fringing.
However, on the plus side, close-ups were competently handled (although the small LCD made framing shots less easy than with current Ixus cameras). Digital zoom shots were also very good, with plenty of detail and few visible aberrations. The Face Detection function worked as well as it did in other Canon digicams we've tested. Designed primarily for snapshooters, it's not a function serious photographers are likely to require.
The optical image stabilisation system, however, was quite impressive and has genuine value for photographers. We estimate it allowed us to shoot at shutter speeds at least three stops slower than would otherwise be required.
A half-second exposure with the image stabiliser switched off.
A half-second exposure with image stabilisation.
The test camera's flash was relatively weak, requiring an ISO setting of at least 400 to illuminate an average-sized room. Image noise became apparent at ISO 400 and increased to the point where shots taken at ISO 1600 were severely noise-affected. Long exposure times further increased imge noise. The location of the flash tube made the TX1 prone to red-eye, although it was removable via in-camera processing.
White balance performance was typical of most digicams, with the auto setting failing to remove colour casts and the pre-sets and manual measurement delivering more natural colour rendition. Incandescent lighting performance was noticeably worse than fluorescent lighting, as shown in the sample images below. Video performance was generally excellent, especially with the 1280 x 720 pixels setting, which looked great on a widescreen LCD TV set. The LP setting produced the expected drop in video quality, particularly with moving subjects where macro blocks were evident.
It took just over 1.3 seconds to power-up the test camera and extend its lens. We measured an average capture lag of 0.55 seconds, which reduced to less than 0.1 seconds with pre-focusing. Shot-to-shot times averaged 1.2 seconds without flash and between 3.2 and 5.5 seconds with flash (depending on battery status). The test camera recorded a continuous sequence of shots at 0.4 second intervals, slowing slightly at around 18 shots. It took roughly 10 seconds to process a burst of 20 shots.
The PowerShot TX1 is supplied with the standard Canon software bundle containing ImageBrowser (Mac), ZoomBrowser (Windows), Photostitch 3.1, EOS Utility 1.1 and Camera TWAIN driver. Two user guides are provided: a Basic instruction manual and a more comprehensive Advanced manual that is well-presented and easily understood.
IMATEST GRAPHS
Low ISO resolution.
High ISO resolution.
SAMPLE IMAGES
Auto white balance with fluorescent lighting.
Auto white balance with incandescent lighting.
Close-up.
Digital zoom.
Coloured fringing in outdoor shots. (Image magnified to 200%.)
ISO 80
ISO 400
ISO 1600
Image sensor: 5.76 x 4.29 mm CCD with 7.4 million photosites (7.1 megapixels effective)
Lens: 6.5-65 mm f/3.5-5.6 zoom lens (39-390mm in 35mm format)
Zoom ratio: 10x optical, up to 4x digital
Image formats: Stills – JPEG (Exif 2.2); Movies – Motion JPEG/WAV (stereo)
Image Sizes: Stills - 3072 x 2304, 2592 x 1944, 2048 x 1536, 640 x 480; Movies – 1280 x 720, 640 x 480 at 30 fps; 320 x 240 at 30 or 60 fps.
Shutter speed range: 15-1/2500 sec.
Image Stabilisation: Lens-shift (Continuous, Shoot Only and Panning modes) for still images only
Exposure Compensation: +/- 2 EV in 1/3-stop increments
Focus system/range: TTL AF with Face detect, 9-point AiAF and 1-point AF (fixed: centre) options; range 50 cm to infinity; macro to 10 cm
Exposure metering/control: Evaluative, centre-weighted and spot metering; Program AE plus 7 scene modes and 11 My Colours modes
ISO range: Auto, ISO 80, 100, 200, 400, 800, 1600
White balance: Auto, Pre-set (Daylight, Cloudy, Tungsten, Fluorescent, Fluorescent H) + Custom
Flash modes/range (ISO auto): Auto, On, Off, Slow-synchro (Red-eye reduction is available); range 50 cm to 2.0 m
Sequence shooting: Approx 2.2 shots/sec
Storage Media: SD, SDHC, MMC cards (up to 4GB)
Viewfinder: n.a.
LCD monitor: 1.8 inch Low-temperature polycrystalline silicon TFT colour LCD
Power supply: NB4L rechargeable lithium ion battery
Dimensions (wxhxd): 88.8 x 29.0 x 59.9 mm (ex. protruding parts)
Weight: Approx. 220g (without battery, card and strap)