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Pentax Optio S5z Digital Camera Review
by Howard Creech -  10/29/2005

The Pentax Optio S5z - The little digital camera in the Altoids tin grows up

Pentax was not really a player in the digital camera wars until early 2003 when (in a brilliant marketing move) the company introduced the World's smallest 3 megapixel digital camera, the Optio S, pictured nestled in an empty Altoids tin. Advertising has always been about image and Canon's super popular ultra compact S230 digital ELPH looked positively bloated, when compared to the tiny Pentax Optio S.


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The Pentax Optio S5z is the fifth generation update of that original micro-cam, a stylish ultra compact brushed aluminum digital camera with 5-megapixel resolution, a 3X zoom, and a 2.5" LCD screen (and yes it's still small enough to carry around in an Altoids tin). What really sets the S5z apart is that it's fun, it's incredibly easy to use, and it has the ability to deliver very good images (despite its diminutive size).

NUTS & BOLTS

Viewfinder/LCD

Unlike the original Optio S, the Optio S5z doesn't have an optical viewfinder, which means all framing and composition must be done using the camera's LCD. The first Optio S had a 1.6 inch LCD screen, so the S5z's much larger 2.5 inch screen provides a lot more viewing area. The LCD screen covers almost 100% of the frame and has an anti reflective coating to improve visibility in bright outdoor lighting. The S5z's LCD is relatively bright and fluid, but a bit grainy (due to its modest 110,000 pixels resolution). The S5z's 2.5-inch LCD screen is difficult to use at times, on overcast days or in open shade it is easy to use, but in bright sunlight it fades pretty badly making it very difficult to compose or review images and adjusting the brightness level doesn't help much. Pentax's highly distinctive take on color interpolation makes some colors look slightly off and a bit under saturated when viewed on the LCD screen, but when viewed on a larger monitor they are generally fairly accurate, although blue/green is often visibly off. The LCD display furnishes all the data/status information most shooters are likely to need. The live histogram display provides users with an easy to understand graphic representation of the image (for checking over/under exposure).


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Lens

The S5z's zoom is a reasonably fast all glass (6 elements in 5 groups with 2 aspherical elements) Pentax SMC (Super Multi Coated) f2.6-f4.8/36.5-107mm (35mm equivalent) zoom. A built-in lens cover slides out of the way when the camera is powered up allowing the lens to telescope out of the body. The process is reversed when the camera is powered down; the lens retracts fully into the camera body and the built in lens cover slides into place automatically to protect the front element.

Pentax's optical engineers had to come up with an optical zoom lens that could be shoehorned into a space less than an inch in depth. They shortened the length of the 3X zoom by making the central elements swing up out of the light path allowing the front and rear groups to be compressed so they could be squeezed into a smaller space when the lens is retracted into the camera body.

The complex lens design results in some minor but noticeable loss of sharpness at longer shooting distances and corners that are a bit soft throughout the zoom's range. Barrel distortion (straight lines bow out from the center) is moderate and pincushion distortion (straight lines bow in toward the center) is about average. Chromatic aberration (purple fringing) is well controlled but visible in high contrast color transition areas. Optical performance was better than expected (I expected to see some vignetting and maybe even a little coma) but the zoom's performance is actually quite good (for such a tiny and complex optic). The S5z's Macro performance is exceptional, especially so for an ultra compact digicam.


Red Wooly Worm on Morning Glory [larger]


Crab Spider and Inch Worm on Tahoka Daisy [larger]

Minimum focusing distance (in Super Macro Mode) is 2.4 inches (exceptional performance for an ultra-compact digital camera) but the S5z's complex lens design results in some loss of sharpness at very close shooting distances. However, short focal length zooms provide incredible depth of field, which somewhat ameliorates the S5z's close-in softness.

Like most ultra compact digicams the S5z doesn't permit users to mount add on filters or auxiliary lenses.

Auto Focus

The Optio S5z features an adequate but genuinely unexciting multi-zone (contrast detection) seven AF point auto focus system. At the AF default setting the camera checks the seven fixed focus points to determine which one is closest to the subject and then automatically concentrates focus (closest focus priority) on that AF point. Photographers who insist on absolute control can enable the spot focus option, which locks focus on the center of the frame. Users can also opt to manually place an active AF point anywhere in the frame, using the compass switch (four-way controller). Auto focus is accurate and relatively fast in good light, but the camera stumbles a bit in dimmer light. When the S5z's AF locks focus, the LCD freezes momentarily, which can be disconcerting when you are trying to precisely compose an image.

Manual Focus

The Optio S5z's Manual focus mode allows users to adjust focus manually using the up/down arrows (a distance scale is displayed on the LCD screen). In manual focus mode the center of the LCD image is enlarged, but the grainy resolution of the S5z's LCD screen (even magnified) isn't sharp enough to show the difference between definitely in-focus and almost in-focus.

Flash

The Optio S5z's multi mode built in flash is about half the size of a standard postage stamp, but it does a surprisingly good job. Flash modes include: Auto, Off, On, Auto with Red-Eye Reduction, or On with Red-Eye Reduction. A camera this tiny should be a perfect bar/party camera, but images shot at standard bar/party distances (6-8 feet) fall prey to the weakness of the flash with harsh uneven shadows. Pentax claims the maximum flash range is about eleven feet, but anything more than 6-8 feet from the camera is going to receive only limited flash coverage. The S5z's flash is much too close to the lens, so redeye is an ongoing problem.

Image Storage Media

The Optio S5z saves images to SD/MMC cards and also provides 9.3 megabytes of internal memory.

Image File Format(s)

JPEG

Connectivity

USB 2.0 and A/V out

Power/Battery life

Pentax says the S5z's tiny D-LI8 rechargeable lithium-ion battery pack is good for up to 300 exposures. Based on my experience, 150-180 exposures is a more accurate estimate. Heavy shooters (and/or those who review captured images heavily) will need an extra battery. A battery charger is included and requires about 90 minutes to fully recharge the D-L18.

EXPOSURE

The S5z provides users with two exposure options, Green Mode and Program mode. In Green mode the camera makes all exposure decisions, users have zero input. Program mode (auto exposure with user input) is the default exposure mode and provides easy access to all of the camera's exposure options (Exposure Compensation, White Balance, metering, ISO Sensitivity, etc.). Scene modes include Landscape, Flower, Portrait, Self-Portrait, Sunset, Night Scene, Food, Pet, Text, Sports, and Surf & Snow.

Movie Mode

The Pentax Optio S5z can record video clips (640X480 @ 30 fps) with mono audio. Video clip duration is limited only by the capacity of the installed SD card. The Optio S5z also allows users to add voice notes to their still images.

Metering

The S5z's default light measurement/exposure system is a fairly conservative Multi-Segment type that evaluates the entire image frame to determine exposure. More advanced photographers can opt for either Center-Weighted or Spot metering for challenging lighting or to evoke the retro "look" of classic landscapes and portraits.

White Balance

The S5z's Auto White Balance system does a fairly good job overall, but some Auto WB images show a slight yellowish/orangish color-cast. White Balance pre-sets for specific lighting situations include Daylight, Tungsten, Cloudy, Shade, Custom (manual), and 2 Fluorescent settings (warm daylight or cool white).

Sensitivity

The S5z provides users with a remarkably good Auto Sensitivity mode, plus manual settings for 80, 100, 200, and 400 ISO. The ISO 80 and ISO 100 settings are virtually indistinguishable; Pentax should replace the ISO 80 setting with an ISO 50 Sensitivity option (which was available with earlier Optio S models).


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ISO 100 [larger]


ISO 200 [larger]


ISO 400 [larger]

The S5z's Noise Management is amazingly effective, even the ISO 400 image is quite good. The ISO 200 image shows the yellowish/orangish color-cast I mentioned in the White Balance section.

In Camera Image Adjustment

The S5z's Exposure Compensation mode allows photographers to bias exposure (+2/-2 EV) in 1/3 EV increments to compensate for difficult lighting, evoke mood, or to enhance important elements of the composition.

The S5z also provides a useful range of incremental adjustments for contrast, color saturation, and sharpness.

DESIGN, CONTROLS, & ERGONOMICS

The S5z is diminutive enough to be easily dropped into a shirt pocket, and tough enough to go just about anywhere. The shiny brushed aluminum body, large LCD, and the tiny footprint of the camera tend to attract lots of attention, somewhat limiting the S5z's usefulness for shooting "street" or candid subjects. Menus are straightforward, highly readable, and easily navigated. Controls are logically placed and easily accessed, but the S5z is very small (which means control buttons are small and close together) and that makes it somewhat tricky to use. The S5z's tiny size and brick like shape make it difficult to get a really secure grip on the camera, so It's a really good idea to use the included wrist strap at all times.

Technical Specifications

Included

D-L18 rechargeable lithium-ion battery pack, battery charger, Wrist strap, USB & A/V Cables, (software) CD-ROM, and printed User's Manual

Optional

AC adapter, wireless remote control, leather soft case

PERFORMANCE

Image Quality

The Pentax Optio S5z's image quality is average, which is pretty much typical for ultra-compact digicams. But, the TINY Optio S5z does a better job (in some areas) than similar/competitive micro cams. The ISO 80 and ISO 100 Sensitivity settings produced the best results, but noise is amazingly well controlled even at the ISO 400 setting. There is some noticeable corner softness and colors are somewhat warm and a bit under saturated (at default saturation). Shadow detail is kind of flat, especially in darker areas, but midtone details are pretty good.


The Optio S5z is great for portraits [larger]


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As the shot above of a colorful roadside Louisville landmark shows, the S5z is probably not the best choice for night/low light shooters

Exposures are generally accurate, but there is a slight tendency (in bright outdoor lighting) toward over-exposure and default contrast is a bit soft. In low lighting these problems are exacerbated somewhat by the S5z's weak flash. For many consumers the S5z's tiny size and incredible ease of use are going to be more important than bright, razor-sharp, highly saturated images. Users who plan to stick with 4X6 or 5X7 prints and not shoot too often in dim/low light will probably be very happy with the little S5z, but those who need an occasional 8X10 enlargement may find the ultra-compact size/image quality tradeoff more onerous than they are willing to accept.

Timing/Shutter Lag

Overall the Pentax Optio S5z is pretty quick. Start up time (boot-up cycle) is about 3 seconds, but shutter lag is surprisingly short for an ultra compact digital camera -- virtually real time (about 1/10th of a second) with pre-focus and about half a second from scratch. Auto Focus speed is a bit quicker than average and shot to shot times (about 2 seconds) are on the quick side of average. Write to card times are in the average range.


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If you can see Henri Cartier-Bresson's "Decisive Moment" coming together, the Optio S5z is quick enough to capture it.

A Few Concerns

Pentax's nifty little 3X zoom lens exhibits above average barrel distortion at the wide-angle end of the zoom range, but pincushion distortion is well controlled at the telephoto end of the range. Chromatic aberration (purple fringing) is well controlled and shouldn't be a much of a problem. The S5z's zoom is a bit soft in the corners but there is no vignetting (dark corners).

Minor color anomalies and the S5z's slight tendency toward over exposure in outdoor settings may cause some heartburn for more advanced photographers, but the S5z's target audience probably won't be bothered at all by these shortcomings.

Switching between the SD card and the internal memory is more complicated than it should be and users can't review images saved to the internal memory cache unless the SD/MMC card is removed.

Because the camera is so tiny, the zoom and flash can't be adequately separated (to avoid essentially being on the same plane) which means that red-eye will be an ongoing and largely insurmountable problem.

Conclusion

The S5z is an amazing piece of cutting edge miniaturization and precision engineering and I really had fun using it. Obviously, tiny digital cameras can't be expected to compete with full sized units in terms of image quality and battery life, so consumers who place a high value on ultra compact size must be prepared to accept certain logical (and unavoidable) limitations. Based on its amazing ease of use and decent performance the Pentax Optio S5z is a great choice for first time digicam buyers, busy folks who like trendy techno-toys, casual photographers who want a camera small enough to take along everywhere they go, and style conscious snap shooters.

Pros
Ultra compact, 5 megapixels, 2.5" LCD Screen, very impressive noise management

Cons
Few manual controls, LCD colors are slightly "off", tendency toward over-exposure