Pentax Z10 Exposure

Saturation & Hue Accuracy
Some hue inaccuracies and undersaturation, but still pretty good color overall. Noticeable shifts in cyan and blue, however.

Saturation. The Pentax Optio Z10 oversaturates strong blue tones a fair amount, but actually undersaturates bright yellows. The strong reds and greens were just about right, though some consumers may find their saturation levels a bit flat. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Here, with the color balanced properly for the light source, the Pentax Z10's skin tones were a little flat and clay-like, with a hint of warmth. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.

Hue. The Pentax Optio Z10 showed a few large color shifts relative to the correct mathematical translation of colors in its subjects. Most notable, the cyans and blues were pushed toward violet and purple, giving the blue skies an almost purplish tint. Warmer colors were shifted as well, with yellow toward green, orange toward yellow, and red toward orange. Hue is "what color" the color is.

Exposure and White Balance

Indoors, incandescent lighting
Good color with the Manual white balance setting (very warm with Auto). Slightly higher than average positive exposure compensation required.

Color balance indoors under incandescent lighting was quite warm in Auto white balance mode, while the Incandescent and Manual options produced more accurate results. As the Incandescent setting had a hint of a pink cast, we settled on the Manual option as the most accurate overall, though it had the slightest yellow tint. The Optio Z10 required a +1.3 EV exposure compensation boost to get a good exposure, slightly more than average for this shot. Though really it was a toss-up between the +1.3 and +1.0 EV exposures, as one was too dim and the other a shade too bright. Overall color with the Manual white balance setting is quite good, though the blue flowers are quite purplish. (Many digital cameras reproduce these flowers with a dark, purplish tint, so the Optio Z10 struggled a bit here.) Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.

Outdoors, daylight
Overall good exposure, though slightly undersaturated reds, but a very intense sky. High contrast with limited shadow detail.

Outdoors, the Pentax Optio Z10 produced a good overall exposure, despite slightly high contrast under the harsh lighting. Shadow detail was limited, with blurring from some noise suppression as well as decreased definition due to actual noise pixels themselves. The highlights held onto a fair amount of fine detail, however. Despite what appears to be undersaturated reds and greens (though saturation is actually close to accurate), overall color is pretty good. The blue sky is a little too intense, however. The camera's contrast and saturation adjustments may be good options in situations like this.

See full set of test images with explanations
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Resolution
Moderately high resolution, 1,200 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,200 lines per picture height in both directions, with extinction at around 1,700 lines. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Fairly sharp images overall, though visible edge-enhancement on high-contrast subjects and a fair amount of noise suppression in the shadows.

Sharpness. The Pentax Optio Z10 captures fairly sharp images, though high contrast subjects like the crop above left show a fair amount of edge enhancement. Noise suppression does smudge detail here a little, particularly in the foliage and to a small degree in the bricks. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.

Detail. The crop above right shows visible noise suppression and smudged detail in the darker areas of Marti's hair. Individual strands become lost in the shadows, and some chroma noise artifacts affect definition as well. Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

ISO & Noise Performance
Low to moderate noise at the normal sensitivity settings. Very high noise with strong losses in detail and color shifts at the highest settings.

The Pentax Optio Z10 produced fairly low image noise at its lower ISO settings, though noise pixels start to interfere with detail at ISO 200. At ISO 400, noise is high but not unexpected. Noise pixels are a little bright however, particularly the blue pixels. At ISOs 800 and 1,600, fine detail is almost completely gone. Color shifts with the strong purple and yellow noise pixels, and fine detail definition is extremely limited. Results at ISO 3,200 are really unusable, as the image is almost completely blue and there is really no fine detail to speak of. The bottom line? Passable quality at the lower ISO settings, but don't rely on the higher ISOs if detail is important.

Extremes: Sunlit and low light tests
High resolution with pretty good overall detail, but high contrast and limited shadow detail. Pretty good low-light performance, capable of capturing bright images in near darkness, though only at the highest ISOs.

Sunlight. The Pentax Optio Z10 produced high contrast in the test above, with hot highlights and deep shadows. Detail is limited in the shadows, thanks to noise and noise suppression, though the highlights still hold onto a fair amount of detail. The camera required about average compensation to get proper exposure of skin tones at +0.7 EV, though even here, the highlights are a little too bright. The overall image is too dim at +0.3 EV, and there's some vignetting in the corners of the frame. The Pentax Z10's contrast adjustment helps a little, but it's better to use fill flash in situations like the one shown above, and even better to shoot in the shade when possible.

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here.)

Low light. The Pentax Optio Z10 performed about average for a pocket camera on the low-light test, though it only captured bright images at the lowest light level at the higher sensitivity settings (ISO 800 and up). At the lowest setting, ISO 64, images were only bright at the one foot-candle light level, about the equivalent of city street lighting at night. Noise is quite high at the higher ISOs. Color balance was good with the Auto white balance setting. The camera's autofocus system was able to focus on the subject almost down to the 1/4 foot-candle light level unassisted, and the camera unfortunately didn't offer an AF assist lamp for darker conditions. Keep in mind that the longer shutter times here require a tripod for the best exposures. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) For such applications, you may have better luck with a digital SLR camera, but even there, you'll likely need to set the focus manually. For information and reviews on digital SLRs, refer to our SLR review index page.

Coverage and Range
A fairly powerful flash at close range, though not a match for the camera's 7x optical zoom. Our standard shots required slightly higher-than-average positive exposure compensation, coverage was pretty uniform.

Coverage. Flash coverage was slightly uneven at wide angle, with falloff in the corners and at the edges. At full telephoto, the target was too far away for the flash to illuminate it. In the Indoor test, the Optio Z10's flash underexposed our subject a little at its default setting, requiring a +1.0 EV exposure compensation adjustment to get bright results (though this is a little too harsh). The camera's Slow-Sync flash mode produced slightly brighter and more even results, though with a stronger pinkish-orange cast from the room lighting, and some bluish tints in the shadows.

ISO 100 Range. At wide angle, flash shots at ISO 100 remained fairly bright out to a distance of about 8 feet, decreasing in brightness from that point on. At full telephoto and ISO 100, the target at 6 feet was dim, and the images darken gradually from there.

Manufacturer Specified Flash Test. In the wide angle shot above, the Optio Z10 performs about as Pentax says it will, producing a good exposure at the rated distance with its ISO set to Auto, though it selected a rather high setting at ISO 800. At telephoto, the image is a hint dim, despite the large jump in ISO. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.

Print Quality
Good print quality, good color, sharp 11x14 inch prints. ISO 400 images are soft but usable at 8x10, ISO 800 shots are usable at 5x7.

The Pentax Z10 had enough resolution to make good looking 11x14-inch prints at ISO 64. 13x19-inch prints were reasonable, but softer and chroma noise shows up in some places. ISO 200 shots are better than expected at 11x14, with good color and detail. ISO 400 shots are soft at 11x14, but better at 8x10. ISO 800 shots are usable at 5x7, but too noisy for 8x10. Colors start to saturate in places, and fade in others at ISO 800 as well. ISO 1,600 shots are good at 5x7, better at 4x6. ISO 3,200 shots are not usable at 4x6. Overall, better than expected performance.

Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon i9900 studio printer, and on the Canon iP5200 here in the office. (See the Canon i9900 review for details on that model.)