Testing / Performance
*To test the accuracy of the Optio S5z’s reproduced color tones, we recorded a series of images of an industry standard GretagMacbeth color chart and imported the results into Imatest Imaging Software. The software analyzes the uploaded files and produces a series of charts indicating the degree in which each tone strays from the original. The S5z’s color results are displayed in the graph below. Within each color tile, the outer square is the camera’s produced tone, while the vertical rectangle is the ideal. The inner square displays the camera’s produced hues after they’ve been corrected for luminance.
The graph below displays the same color information as above, in a more linear and quantitative manner. The circles are the camera’s produced tones, while the corresponding squares are the original ideal. The length of the line linking the two shapes represents the degree of error for that particular tone.
The Pentax S5z surprised us with its substandard color performance, earning just a 3.73 overall color score. Many colors produced by the camera were extremely under-saturated, resulting in a dull overall color pallet, while others stayed completely from their intended hue. Cooler tones, namely tones in the blue and green channels, were grossly inaccurate, and some orange tones shifted colors to near white (#16 and green #11). While many compact digital cameras earn low scores on color accuracy tests, none we’ve tested so far have strayed so significantly from the ideal tones. The S5z, like many compact cameras, will consistently produce images with inaccurate color tones; however, the problem is severe enough on the S5z to render many of the produced images unusable.
Still Life Scene
Below is a shot of our highly allegorical still life scene photographed with the Optio S5z.
Click on the above image to view a full resolution version (CAUTION: the linked file is very large!)](https://www.reviewed.com/cameras/viewer.php?picture=Pentax-S5z-StillLifeLG.jpg)
Resolution / Sharpness*(2.54)
*To test the resolution and sharpness of images produced by the Pentax Optio S5z, we captured an abundance of images of an ISO resolution chat and imported the results into Imatest Imaging Software. The software analyzes the image and determines the number of horizontal and vertical pixels active in forming the composition. Because no camera ever quite uses all of the advertised megapixels, we classify cameras that utilize 70 percent of their advertised pixel count as "good" performers, while cameras that use more than 80 percent are "very good." Anything exceeding 90 percent is "excellent" and quite a rare find.
The Pentax Optio S5z again performed far below expectation, forming images with just 2.54 active megapixels. This is just 52 percent of its advertised resolution and far below most competing point-and-shoot models. For users looking to display their images as they shoot on the camera’s LCD, the lack of resolution might not be too much of an issue; however, for those looking to make prints, the S5z will show its limitations.
Noise – Auto ISO*(6.71)
*Particularly important for point-and-shoot cameras, since they are designed as snapshot imagers, is their ability to produce images in full auto mode with sharp definition, good color reproduction and low noise. While sharpness and color can be adjusted post-capture, it is far more difficult to cleanly remove noise. We also test for noise, using our GretagMacbeth color chart and Imatest Imaging Software.
The Pentax Optio S5z performed well in auto mode, earning a 6.71 overall score. This is quite high for a point-and-shoot imager and given ample lighting, the S5z should attain usable images without much perceivable noise.
Noise – Manual ISO*(9.77)
*For cameras that offer alterable ISO settings, we test for noise at each offered setting and import the results into a regression analysis to determine an overall noise score. Incremental noise readings are plotted in the chart below; the horizontal axis contains the S5z’s ISO ratings, while the vertical axis displays the emitted noise.
In sharp contrast to the S5z’s color reproduction, this camera attained one of the strongest noise scores for its styling. In fact, to balance out the abysmal color score, the S5z’s 9.77 overall noise score is the highest noise score we have achieved from a point-and-shoot camera that contains a typical 80-400 ISO range. Some point-and-shoot models have scored better, but this is largely attributable to a more expansive sensitivity range, rather than performance at the offered settings. The S5z produces clean images across its ISO range, even at its ISO 400 setting. Many compact cameras, particularly those that heavily rely on automatic settings, are strong up to ISO 200 and then show a significant decline. This is not true with the S5z and potential consumers should see this as an extreme advantage. Unfortunately however, users that wish to take advantage of this performance strength will have to expend additional efforts correcting color post-capture.
Low Light Performance*(1.5)
*We tested the low light capabilities of the Optio S5z by exposing a series of images at decreasing light levels. Shots were taken at 60, 30, 15, and 5 lux to sample the camera’s performance capabilities in common low light situations; 60 lux appears similarly to a bedroom after dusk, illuminated by two small table lamps, while 30 lux equates roughly to a single 40 watt lightbulb. 15 and 5 lux indicate the camera’s recording potential in near darkness. Images are recorded at the camera’s highest ISO setting without the assistance of a flash, with white balance customized for each shot.
Click on any of the above charts to view additional image analysis
While the Pentax S5z handled noise admirably in reasonable lighting, the 400 ISO limitation proved to be a substantial roadblock for the camera’s low light potential. Even at 60 lux, the brightest of our low light setups, the camera could not produce an acceptable image. The lack of light sensitivity in the S5z’s imaging sensor hindered it from producing a visible image, and the already compromised colors lost further distinction and begin to blend together. The drop to 30 lux resulted in images that were barely pronounced and certainly not usable. The lack of sensitivity means users of the S5z who are intent on night scenes will have to adjust to the camera’s limited flash capabilities (see the components section of the review for further elaboration) or look elsewhere.
**Speed / Timing
***Start-up to First Shot (6.41) *
It’s fortunate that the Optio S5z includes a long enduring lithium-ion battery, because users will have to leave the camera on in case of that fleeting memorable moment. In the four seconds it takes the S5z to wake up and ready itself for its first shot, the moment will have long since passed.
*Shot to Shot Time (8.91)
*Even with a continuous shooting mode, the S5z is not a rapid performer. The camera will burst until the card is filled; however, it will still require over a second between recorded frames.
Shutter to Shot Time (8.96)
Shutter lag is generally the most pertinent speed characteristic to snapshooters. With a lag of just 0.02 seconds, the S5z should minimize captures of blinked eyes and turned heads.