Kodak EasyShare Z812 IS Digital Camera Review
Read an independent, expert digital camera review of the Kodak EasyShare Z812 IS digital camera.
*Ideally, the colors a camera reproduces should be very close to how they appear in reality. All cameras reproduce colors differently, from blue skies to grass greens to skin tones, and some are more accurate than others. We test color accuracy by photographing an industry standard GretagMacbeth ColorChecker test chart and comparing the colors the camera reproduces with the known colors of the test chart. The ColorChecker chart consists of 24 colored tiles from around the color spectrum. The image below compares the colors the Kodak Z812 IS reproduces with the ideal colors of the ColorChecker. The outside squares show the colors the Z812 IS reproduces, the inner squares show the ideal color of the chart corrected for exposure, and the small inner rectangles show the ideal chart color under a perfectly even exposure. The Z812 IS has no manual white balance setting, so this test was shot under tungsten studio lights with the camera set to Tungsten white balance.
Comparing the outer squares with the inner squares, you can see a number of the color tiles don’t match, especially the yellows. The reason the small rectangles look lighter than the squares is because the Z812’s colors are most accurate when the image is slightly underexposed. The graph below shows this information in a more quantitative way. The colors the Z812 IS reproduces are shown as squares on the color spectrum, and the known colors of the ColorChecker chart are shown as circles. The length of the lines connecting the squares and circles shows the amount of color error.
The Tungsten white balance setting is very accurate considering there is no Manual white balance option. That said, the Z812’s color accuracy does not live up to many other cameras released this year that can manually white balance. As the graph shows, many colors are drastically shifted, especially the yellows and blues. Shifting the yellows toward green may improve the look of foliage-filled landscape shots, for instance, but could also make people look sickly or sunsets look unnatural. The blues are shifted toward red so much that blues skies look purple. Overall, the Z812 IS has below average color accuracy.
We test resolution performance by photographing an industry-standard resolution test chart and varying the focal length, aperture, and shutter speed. We run the images through Imatest, which determines resolution in terms of line widths per picture height (lw/ph), as well as the amount of sharpening applied inside the camera by the processor. The unit lw/ph represents the number of equally-spaced, alternating black and white lines that can fit across the image frame before becoming blurred.
The 8.1-megapixel Z812 IS is sharpest when the camera is set to ISO 64, f/3.2, and a 16mm focal length. The camera resolved 1800 lw/ph horizontally with 0.9 percent oversharpening, and 1769 lw/ph vertically with 0.2 percent oversharpening. These are impressive numbers, and the ever-so-slight sharpening doesn’t introduce ugly image artifacts such as jagged edges or ghosting. There is a hint of noise reduction, however, even at such a low ISO speed. This makes edges slightly chunky. The camera keeps images quite sharp across the entire frame, but suffers from chromatic aberration in the corners. Overall, though, the Z812 IS has very good resolution.
Noise – Manual ISO*(5.85) *
Image noise is an unavoidable issue that has forever plagued digital cameras. "Noise" refers to the fine grainy or splotchy patches scattered uniformly throughout digital images. Noise is most apparent when viewing images in a large size or shooting at high ISO speeds. We test noise levels by photographing our test chart under bright, even studio lights at all ISO speeds the camera offers. We run the photos through Imatest, which measures noise in terms of the percent of image detail it destroys.
The Kodak Z812 IS keeps noise levels quite low, especially from ISO 64 to 800. However, closer inspection reveals extreme amounts of noise reduction, especially at higher ISO speeds. The noise reduction becomes most obvious in the jump from ISO 200 to 400, where edges start to blur and regions of solid tones look chunky. Noise reduction permanently destroys a significant amount of image detail, which illustrates the tradeoff between noise levels and noise reduction. Lots of noise is ugly, but so is lots of noise smoothing.
Noise – Auto ISO*(3.75) *
We also evaluate noise levels with the camera set to Auto ISO, shooting under the same bright studio lights. The K812 IS shot at ISO 64 and had very low noise. It is great to see the camera chose the lowest possible ISO speed to shoot at, and it gets a very good Auto ISO score.
White Balance* (6.20) *
As we mentioned in the Color section above, accurate white balance is critical for producing accurate colors. Every type of light source has a different color cast to it, and a camera must be able to adjust accordingly. We test white balance accuracy by photographing the ColorChecker chart under four different types of light: flash, fluorescent, outdoor shade, and tungsten. We test both the Auto white balance setting and the presets.
Set to Auto white balance, the Z812 IS’s accuracy is mediocre under fluorescent light and outdoor shade, and poor under tungsten light and when using the flash. Users should strongly consider using the white balance presets with this camera.
The Z812’s tungsten and outdoor shade presets are very accurate, but it performs poorly under white fluorescent light. If you are concerned about color casts in your photos, use the camera’s white balance presets, except for the fluorescent preset.
Still Life Sequences
Click to view the high resolution image
**Low Light ***(8.09)
*We’ve seen how the Z812 IS performs in ideal shooting conditions; now let’s look at its image quality in low light. We test color and noise levels in low light by photographing the ColorChecker test chart at light levels of 60, 30, 15, and 5 lux. Sixty lux is approximately the amount of light in a room lit softly by two table lamps, 30 lux corresponds to a room lit by a single 40-watt bulb, 15 lux is similar to a room lit solely by a television, and 5 lux is quite dim and tests the limit of the camera’s sensor. All shots are taken at ISO 1600.
In low light, colors stay almost as accurate as in bright light, and noise levels stay relatively low but are subjected to unattractive noise smoothing. The camera exposes properly at all light levels, showing its versatility. Metering is also very consistent at low light levels.
We also test performance in long exposures, and the Z812 IS can take exposures up to 16 seconds in duration. This test is shot at ISO 400. Color suffers in long exposures, but noise levels stay very low. Again, the camera applies heavy noise reduction, which destroys some fine image detail but removes lots of ugly noise that can plague low light photos. Overall, the Z812 IS is impressive in low light, and shows it has use beyond brightly lit scenes.
**Dynamic Range ***(6.78) *
Dynamic range, another important image quality factor, refers to how broad a tonal range a camera can detect. In other words, it tells how much detail a camera can capture in high contrast scenes. Examples include wedding photography, where some cameras may have trouble capturing detail in the white wedding dress and black tux in the same photo, or a landscape in bright sunlight, where there are bright highlights as well as dark shadows. We test dynamic range by photographing a backlit Stouffer step chart at all ISO speeds. The Stouffer chart consists of a row of gray rectangles that vary in tone from brightest white to darkest black. The more rectangles a camera can discern, the better its dynamic range.
Due to its low noise levels, the Z812 IS has very good dynamic range at low ISO speeds. Again, this comes at the cost of fine image detail, but will help highlights from blowing out and shadows from becoming completely black. Keep this camera at low ISO speeds for optimal performance. Overall, the Z812 IS scores well in dynamic range.
**Speed/Timing **– All speed tests were conducted using a Kingston Ultimate 120X 2GB SD Card, with the camera set to highest resolution and best quality, unless otherwise noted.
Startup to First Shot (8.6)
The Z812 IS fires its first shot relatively quickly, taking only 1.4 seconds.
*The Z812 IS has two Burst modes and one Bracketing mode. In the First Burst mode, the camera takes five shots, each 0.6 seconds apart. The Second Burst mode takes shots every 0.6 seconds continuously for 18 seconds, but only saves the last five. The Bracketing burst mode takes three shots 0.5 seconds apart, each at a different exposure value.
The Z812 IS has no measurable lag when the shutter is held halfway down and prefocused, and a short lag of 0.2 seconds when not prefocused.
The camera takes a whopping 10 seconds to process one 2.2 MB full-resolution fine quality photo taken at ISO 100. This is incredibly long for one photo, and makes viewing photos very frustrating if you have quickly snapped several photos in a row.
Video Performance* (4.71) *
Bright Light – 3000 lux
To evaluate color and noise performance using the Movie mode, we capture footage of our color charts lit with bright studio lights at 3000 lux. The Z812 IS has good color accuracy under these lights, and very low noise.
Low Light – 30 lux
We also record footage with the lights dimmed to 30 lux. In lower light, the camera has even better color accuracy, but significantly more noise. However, it is still a good camera for capturing decent videos in a wide range of shooting conditions.
The Kodak Z812 IS is one of the first digital cameras to record video in HD (1280 x 720 pixels). We put its video resolution to the test by capturing footage of our resolution test chart and running it through Imatest. The camera resolved 318 lw/ph horizontally with 26 percent undersharpening, and 223 lw/ph vertically with 26 percent undersharpening. These numbers aren’t any better than standard definition video (640 x 480 pixels) on other digital cameras, which suggests the HD capability provides output versatility, but not improved performance.
**We take cameras out of the lab and down to the street to get a look at how Movie modes capture the motion of cars and pedestrians. The Z812’s video looks good, with nice (though oversaturated) colors and decent motion. However, the metering is inconsistent and often overexposes, objects moving off the frame can appear jerky, and there is soft focus and some compression artifacts. The video isn’t nearly as crisp as that of the Canon Powershot TX1, one of the only other digital cameras to shoot HD video, but lacks the ugly imaging artifacts and exposure bleeding that plagues TX1 video. The HD option provides a larger picture than shooting in standard definition, but it exaggerates the soft focus and compression artifacts. This camera is nice if you need to be able to play video on your HDTV, but it won’t give you significantly better video quality.
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