Canon PowerShot G1 X: Performance

Performance

The sensor and price tag are sized like a DSLR, but the camera carries a Powershot designation and sits at the top of Canon's compact point-and-shoot pyramid. Which camera will show up when the power button gets turned on?

Shooting Performance
The G1 X presents a shooting screen and focus point in about 2 seconds after pushing the on button and I was able to get off a first shot in about 3 seconds. There is a start-up image option in the setup menu that is enabled by default which displays a Canon logo before the shooting screen comes up, but disabling this feature does not shorten start up time. Single shot-to-shot times ran about 3 seconds with a 16GB, 95MB/second SDHC UHS-1 memory card. The camera features an "HQ" option in the scene menu that will capture up to 6 full resolution images at a continuous shooting rate of about 4.5 frames per second (fps) - the monitor goes blank during this burst shooting, but the viewfinder is available to help track moving subjects. Write times for these 6 images ran about 3.5 seconds.

AF Acquisition (press-to-capture, no pre-focus)

Continuous Shooting

*Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

The normal full resolution continuous shooting rate (focus and exposure determined by the half push of the start of the burst) is about 1.9 fps and the G1 X was happily humming along at this rate when I called off the experiment at 50 frames. The write time for 25 images captured in this fashion was about 4.5 seconds. Switching to a 16GB class 10 SDHC (30MB/sec) card produced a 5 second write time for 25 images, so there doesn't appear to be any significant gains to justify the added cost of really high-speed media in the G1 X. The camera also offers a continuous shooting rate of about 0.7 fps while focusing between shots.

Shutter lag came in at 0.01 seconds but AF acquisition time was a not surprising 0.65 seconds - the G1 X seemed a bit pokey during autofocus, even in good lighting conditions. There is an autofocus assist lamp for use in dim conditions.
While shutter lag time is good, the shutter itself has a very light detent at the half push point that initiates focus acquisition. During portions of this review I was also shooting the Panasonic ZS20 and switching between cameras consistently found me taking shots with the Canon prematurely by going right through the half push and initiating capture before AF was acquired.

The Panasonic had a slightly firmer detent at half push and this was enough to throw me off with the Canon. Once the Panasonic review was complete and I was shooting exclusively with the Canon it was a fairly simple matter to adapt to the lighter feeling shutter. Even so, I'd have liked Canon to have put it just a pinch more resistance at the half push point - the G1 X is an easy camera to push past the focus point on.

Stabilization in the G1 X is enabled in the continuous mode by default - the user may set a "shoot only" mode or disable stabilization altogether. There is also a power stabilization mode (enabled by default) that improves stabilization for video capture using the long end of the zoom lens.

Flash range on the G1 X is listed as about 1.6 feet to 23 feet at wide-angle and 3.3 feet 10.2 feet at telephoto (auto ISO). Recycle time is listed as 5 seconds or less with a fully charged battery and I experienced times more the 6 to 6.5 second range with the battery state about 3/4 charged. Here's a close up shot of Kiwi and another from a distance at Disneyland.

Battery life is listed as approximately 250 shots with the monitor on but about 700 with it off, so if you don't need precise image composition making use of the viewfinder as much as possible can significantly enhance battery life. Monitor-only shooters will want to have a couple of spare batteries for all-day sessions.

Lens Performance
The 4x Canon zoom lens on the G1 X offers a fairly fast f/2.8 maximum aperture at wide-angle but slows appreciably to f/5.8 at the telephoto end. The 28 to 112 mm focal range is not particularly wide or long, so the G1 X will do better as an all-around general-purpose shooter rather than trying to capture subjects requiring significant wide-angle or long telephoto lens performance.

There's a very slight amount of barrel distortion at wide-angle while the telephoto end of the lens seems fairly distortion free. Corners look a little bit soft at wide-angle while the telephoto end again produced a good performance - sharpness is fairly uniform across the frame. There was a little bit of chromic aberration (purple fringing) at wide-angle in some high-contrast boundary areas, but the effect was very well controlled and required magnifications on the order of 400% to be readily visible. The telephoto end of the zoom was better still with just a few hints of purple here and there, and definitely difficult to pick out. All in all, a very good optical performance by the G1 X lens.

Video Quality
Video quality is quite good with the G1 X, with automatic autofocus and zooming available during video capture. Transition into or out of video capture mode via the one touch dedicated movie button is fairly speedy, with perhaps a 1 second delay before video capture is initiated and far less delay at shutdown. The microphone is wind sensitive but there is a wind cut feature available and during zooming a few noises associated with that process may be recorded.

Download Sample Video

Because the camera is equipped with a CMOS sensor, rolling shutter effect is a consideration when panning across scenes containing vertical straight lines. The G1 X displayed just a hint of rolling shutter in exaggeratedly fast pans, but overall the camera did a very good job dealing with this phenomenon.

Image Quality
Default image quality out of the G1 X was quite good, with pleasant color reproduction and image sharpness. In the event the default settings don't meet with your approval the manual shooting modes offer a custom color setting that allows you to modify contrast, sharpness, saturation, red, green, blue and skin tones. That's the good news. Unfortunately, images are output at 180 dpi which is about the minimum for decent quality reprints and well above the 72 dpi setting for most efficient e-mail transmission. Folks planning to print large images or send e-mails will be resizing to produce the best photos or most efficient e-mails. All the images in this review (with the exception of our studio ISO shots) were resized to 300 dpi and sharpened uniformly but minimally in post processing.

The "my colors" color palette available for the folks who stray beyond the automatic shooting mode will be familiar to previous Canon owners -here are the default, vivid, neutral, positive film, sepia and black-and-white variants.

Default	Vivid
Neutral	Positive Film
Sepia	Black & White

As mentioned earlier, the image effects shooting mode offers users the ability to add a variety of effects to images during capture. Here are fisheye and normal views of Tigr.

Fisheye

Normal

The G1 X provides features such as intelligent contrast (i-Contrast) that seek to expand the apparent dynamic range of the camera by providing more detail in dark areas while retaining detail in in bright areas. There are dynamic range and shadow correction options but Canon warns of the possibility of increased noise when using these tools. Another one of the image effect options is HDR, or high dynamic range, which takes three image captures in rapid fashion and then combines them into a single image. Using this effect requires the use of a tripod and is not suitable for moving subjects.

The G1 X also provides a bracketing feature that can take three images bracketing for either depth of field or exposure. This can be a helpful tool for users intending to perform tone mapping via post processing on images in order to provide a high dynamic range appearance. Unfortunately, the G1 X does not permit exposure bracketing in the manual shooting mode; exposure bracketing is possible in program, shutter and aperture priority shooting modes. Here are two images captured at Mission San Luis Ray - the first is the HDR image effect combining three images into a single image within the camera while the second is the product of post processing three bracketed exposures in specialized HDR software. Both images are resized to 300 dpi and sharpened uniformly.

G1 X HDR

Post-processed HDR

Auto white balance was used for all the images captured for this review and did a good job with a variety of light, including 3200 degree Kelvin sources. In addition to auto, there are daylight, cloudy, tungsten, fluorescent and daylight fluorescent, flash and underwater presets along with two custom settings.

Auto White Balance, 5500k fluorescent light

Evaluative metering is the G1 X default and is recommended for most lighting conditions. As is typical the system could at times clip highlights in bright, high contrast scenes. There are center weighted and spot metering options available for the manual shooting modes.

With an unquestionably large sensor by compact point-and-shoot standards and Canon's latest generation processor technology, even the 14 megapixel resolution of the G1 X offers the promise of fairly decent high ISO noise performance. ISO 100, 200 and 400 proved to be virtually indistinguishable, with perhaps just a few slight hints of graininess in the 400 sample. ISO 800 showed just the slightest deterioration over 400 and 1600 a similar amount of deterioration over 800.

ISO 100	ISO 100, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop
ISO 6400	ISO 6400, 100% crop
ISO 12800	ISO 12800, 100% crop

Quite frankly, a quick glance at ISO 100 to 1600 would find all the settings looking remarkably similar. ISO 3200 shows a bit more deterioration over 1600, but fine details are still remarkably well preserved throughout the frame. The jump from 3200 to 6400 seems to be the tipping point for this sensor/processor combination, as the background grain is more noticeable here and fine details are beginning to show some hints of smudging. ISO 6400, however, is probably still usable for small prints. ISO 12800 suffers from a bit more loss in fine details as well as an increased graininess, but again like 6400, is probably usable for small prints if nothing else will suffice.

Quite simply, the G1 X has by far the best high ISO performance of any Canon compact point-and-shoot camera I've ever reviewed. The progression of noise as ISO sensitivities are raised is reminiscent of noise performance I've encountered in the latest generation DSLRs such as the Canon 60D and Nikon D7000 - a slow and gradual transition toward graininess and loss of fine details as sensitivities rise rather than a more abrupt deterioration at some point that seem to characterize the earlier generation compacts.

Additional Sample Images