Canon PowerShot A460

Color (8.03)
Canon digital cameras tend to do well in color testing, and we tested the PowerShot A460 to see if it could perform as well as its siblings. We photographed a GretagMacbeth color chart which is an industry standard for determining if colors are accurate. The chart consists of 24 color tiles. We uploaded the A460’s images of the chart into Imatest imaging software and it compared the colors of the ideal chart to the colors produced by the Canon A460. Imatest output a modified version of the chart that includes the ideal colors as vertical rectangles, the A460’s colors as outer frames, and the chart's luminance-corrected colors as inner squares.

If this isn’t helpful enough, Imatest also output the following chart that plots the ideal colors as squares and the A460’s colors as circles. Each of the chart’s 24 colors is plotted on the spectrum. The line connecting the two shapes shows the degree of error.

Most of the colors are tightly tethered and there don’t seem to be any colors that are extremely erroneous. Notice many of the circles bending toward the outer edges of the frame? That means the colors are oversaturated – by 16.3 percent, according to Imatest. The mean color error came out to 7.47, which is respectable. It’s certainly not the best Canon we’ve seen, but it is great for the price.

White Balance (15.3)
Auto (14.4)
The Canon A460 showed its best stuff in the white balance test. This digital camera doesn’t have a flash preset, but the automatic white balance setting rendered flash lighting spot on. Generally, the automatic white balance setting was accurate except for in tungsten light.

Preset (16.2)
Under tungsten lights, the preset mode was much more accurate than the automatic setting. In both fluorescent light and outdoor shade, the automatic and preset settings were equally accurate, both performing very well. While it is safe to use the automatic white balance setting most of the time, it is an even better bet to use the presets.

Fluorescent WB - Fluorescent Illumination

Shade WB - Shade Illumination

Tungsten WB - Tungsten Illumination

Still Life Sequences
Click on the photos below to see the high-resolution image.

Still Life Scene
ISO 80	ISO 80
ISO 100	ISO 100
ISO 200	ISO 200
ISO 400	ISO 400

Resolution (3.72)
At a time when megapixels remain the headlining features of digital cameras, the Canon PowerShot A460 has a modest 5.1 megapixels. We tested it to see how effective the resolution was at capturing details by shooting an industry standard resolution chart. We used various focal lengths and apertures to find the sharpest image possible from the camera. We sifted through the images and selected the sharpest shot the A460 produced: it was taken using a focal length of 17mm and an aperture of f/5.

Click to view high-resolution image

The image isn’t the sharpest we’ve seen but isn’t bad for 5.1 megapixels either. It is a bit soft in the corners and the black patterns look a little grayer in the corners too. Imatest quantified these results in terms of line widths per picture height (lw/ph), which describes how many theoretical alternating black and white lines can fit across the frame without blurring. The Canon PowerShot A460 resolved 1313 lw/ph horizontally with 9.3 percent oversharpening. It resolved 1305 lw/ph vertically with 12.4 percent undersharpening.

For comparison sake, here are a few results from other 5-megapixel digital cameras. The Kodak EasyShare V530 resolved 1225 lw/ph horizontally and only 763.7 lw/ph vertically. The Canon PowerShot S2 IS resolves 1490 lw/ph horizontally and 1373 lw/ph vertically. The Kodak is a closer comparison because of its cheap and compact nature, although it was released in mid-2005 so its technology is a bit older. The Canon S2 IS has the same marketed resolution but performs much better: it could be that it simply has a higher quality lens.

Overall, the A460 doesn’t perform as well as the S2 but it does better than most 5.1-megapixel point-and-shoot digital cameras.

Noise – Auto ISO (0.81)
In the bright lights of the studio, the Canon PowerShot A460 automatically selected an ISO 200 setting. This is much too high in this bright lighting and produced way too much noise. In fact, there was so much noise that this camera may have achieved a record low score. The overall auto ISO noise score of 0.81 is definitely the lowest we’ve seen in a very long time. The lesson? Set the ISO yourself.

Noise – Manual ISO (2.51)
The A460 has a short manual ISO range from 80-400 and we tested the noise levels at each of those settings. The chart below shows the settings on the horizontal axis and the percentage of the image lost to noise on the vertical axis.

Even the lowest manual ISO setting has more than 1 percent of its image lost to noise. Things get steadily worse as the ISO setting is bumped up. The most sensitive ISO 400 has an absurd amount of noise - almost 3.5 percent! To compare, the Canon A570’s ISO 400 setting has less than 2.5 percent of noise and the Fujifilm F40fd captured less than 1.5 percent of noise with its ISO 400 setting.

Low Light (6.11)
The A460 isn’t exactly cut out for low light photography with its short ISO range and high noise levels. Nevertheless, we tested it at 60, 30, 15, and 5 lux. The 60 lux test is similar to a living room lit by two soft lamps after dusk: reading is still possible. At 30 lux, eyes start to squint to read as the light is typical of what is emitted from a single 40-watt bulb. The last two tests are very dark and simply find any limitations the image sensor may have.

Low Light Tests
60 Lux	30 Lux
15 Lux	5 Lux

As you can see, there are limitations. The image is quite underexposed at 5 lux, but seems to be okay at 15 lux. In all of the images, however, noise invades and throws its colored speckles about. To its credit, the Canon A460’s color accuracy really didn’t suffer too much in low light or with long exposures.

The amount of noise typically rises when the shutter is opened longer, so we tested the camera’s long exposure noise. The camera took a long time to process these long exposures, hinting that the camera employs a noise reduction system immediately after the shot is taken. The chart below shows the exposure time on the horizontal axis and the percentage of the image lost to noise on the vertical axis.

The most noise hovers just under 5 percent at the 10-second shutter speed and the noise level falls at 15 seconds, indicating that a noise reduction system works heavily between 10 and 15 seconds. Overall, the Canon PowerShot A460 performed better in low light than anticipated.

Dynamic Range (4.11)
To test dynamic range, we photograph a backlit Stouffer test film. The film has a row of rectangles starting as transparent on one end and progressing to black on the other. The images of the film are uploaded into Imatest, which determines how well the camera can capture lights and darks in one shot. A camera’s dynamic range is affected by the selected ISO sensitivity, so we tested the A460 at each of its settings. Below is a chart showing the manual ISO settings on the horizontal axis and the number of exposure values captured by the camera on the vertical axis.

There is a steady decrease in dynamic range throughout the ISO range, although the camera didn’t start well by capturing less than 6 exposure values at its lowest ISO 80 setting. At ISO 400, the camera captures less than 3 exposure values. For comparison sake, the Sony Cyber-shot DSC-T100 captured about 6.5 exposure values at the same ISO setting. The Canon PowerShot A460 isn’t made for photographing weddings or anything, that’s for sure. This is the worst dynamic range score on any camera we’ve tested so far this year.

Speed/Timing
Startup to First Shot (8.0)
It took the Canon PowerShot A460 two seconds to start up and take its first picture. This is decent for a budget point-and-shoot digital camera.

Shot-to-Shot (8.8)
The burst mode on this camera isn’t spectacular. It isn’t made for sports or other action. In the drive mode, the A460 snapped a shot every 1.2 seconds and did so until the memory card was full. It deserves some credit for the lengthy burst, but its slow speed can hardly be called a burst at all.

Shutter-to-shot (9.0)
When the camera was pre-focused the shutter lag was almost immeasurable. Snapping posed portraits shouldn’t be a problem. It’s snapping the action and candid pictures that will be troublesome. It takes the Canon A460 a whopping 0.7 seconds to focus and take a picture. Slow.

Processing (8.2)
After a picture is taken, the camera takes 0.9 seconds to process the shot and record it to memory. This time is lengthened if long exposures are used; when the noise reduction system kicks in, it can take several seconds to process.

Video Performance (1.67)
Bright Indoor Light - 3000 lux   
The Canon A460 has some problems recording video in bright light. The automatic white balance setting just doesn’t work as well in the movie mode. It is way off and contributes to the mean color error tripling! The saturation rockets to 138.1 percent and the average percentage of noise in the image hovers around 0.445 percent. Beware shooting video in bright light: Great Aunt Maude’s purple dress will look more like maroon and her red lipstick will come out an orange-ish hue: it may be scarier in the video than in real life.

Low Light - 30 lux
When the lights were turned low and we recorded a video of a test chart, the mean color error returned to 11.9. This is within normal range and is comparable to the camera’s performance in low light with still pictures. The average amount of noise jumped to 2.58 percent, which is disappointing. The color saturation also had problems – just in the opposite way of the 3000 lux test. This time, colors were dull and undersaturated at only 80.4 percent.


Video Resolution
The Canon PowerShot A460’s videos are recorded at a typical 640 x 480-pixel resolution. We ran some video footage through Imatest software, which numerically defines the sharpness in the same units as still images. Horizontally, the A460’s videos resolved 256 lw/ph with 16.6 percent undersharpening. Vertically, it resolved 313 lw/ph with 6.8 percent oversharpening.

(100% crops)

Outdoor Motion
We took the Canon PowerShot A460 outside and recorded videos of people, babies, dogs, cars, and trucks by our office. The top resolution of 640 x 480 only records 10 frames per second, which is about what some burst modes can do now. Thus, watching moving subjects was something like watching the Terminator robot skeleton. We don’t recommend recording or watching much of the videos from the A460 unless you can handle the inevitable headache. It is hard to look beyond the awfully jerky motion, but when we did we found that the exposure and contrast looked good but the overall scene lacked fine details.