Pentax Optio A20

A new race has begun in the digital camera marketplace. Manufacturers are now rushing to include elaborate systems that promise to reduce the effect of camera shake to their latest models. This doesn't mean the long established quest for more pixels is over. The megapixel race is still very much alive, with higher resolution models pushing the 10 million pixel barrier. In this review Gary Wolstenholme takes a look at whether the Pentax Optio A20 will reign victorious in either of these competitions.

Pentax Optio A20 Specifications

• 10.0 megapixels
• 2.5inch TFT LCD screen
• 3x optical zoom equivalent to 38mm-114mm in 35mm format
• 22 MB Built-in memory
• SD & SDHC memory card compatible
• 15cm macro
• Sensitivity range - ISO64 - ISO800
• Shutter speed range - 1/2000 sec. to 4 sec.

Pentax Optio A20 Build and handling
The finish of the A20 is typical of Pentax' Optio A-series. The metallic finish feesl sturdy with out making the camera overly heavy. A small silver fingergrip is provided on the front, which helps gain a secure hold, whilst aiding one-handed operation. The only negative aspect of the design is the lack of space to rest your thumb on the rear when not operating any of the controls. The knurled space provided is small for all but the daintiest of thumbs.

Pentax Optio A20 Display screen
A 2.5inch LCD screen fills most of the rear of the A20. The display is bright and clear under most conditions, although the shiny protective cover can make it difficult to see in bright light. When shooting, the screen refreshes quickly making it easier to catch the decisive moment.

Pentax Optio A20 Autofocus
Focusing on the A20 is activated with a light press of the shutter button. The autofocus performs well, even in low light conditions although it sometimes struggles in the macro mode with low-contrast subjects, which is typical of cameras of this type. Macro is 12cm with a Super macro facility that can reach 6cm.

Pentax Optio A20 Battery
The A20 uses the same Li-Ion battery found in previous Pentax A-series compact cameras. This is great news for those wishing to upgrade from an older Pentax model, especially if you have already invested in spares for your current camera.

Pentax Optio A20 Memory card
The Optio A20 takes SD cards, which fit into a slot beside the battery. The following are write speeds for different Jpeg quality settings when using a 1GB Sandisk Extreme III card.

Quality setting	Time taken to write to card
10 megapixel Jpeg Fine	2.8secs
10 megapixel Jpeg Normal	2.6secs

I also timed the delay between shots with this camera in the single shot mode.

Quality setting	Shot-to-shot delay
10 megapixel Jpeg Fine	2.60secs
10 megapixel Jpeg Normal	2.28secs

The A20 processes the vast amount of information generated by the 10 megapixel sensor quickly resulting in similar shot-to-shot times as cameras with much lower pixel counts.

Pentax Optio A20 Menu and controls
The controls on the A20 are well laid-out, especially for such a compact design. The most commonly used controls, such as the shutter release and zoom fall directly under finger and thumb allowing for easy one-handed operation.

The addition of a separate green auto-override button makes reverting back to full auto after adjusting features such as exposure compensation quick and simple. Pre-programmed scene modes can be accessed with one touch by pressing the bottom button on the directional pad. This saves having to delve deep into menus to select the program you desire.

Pentax Optio A20 Zoom lens
The A20 includes the same 3x SMC zoom lens as found in previous A-series Pentax cameras. This lens has a reputation of yielding sharp results without the bulk associated with other zoom lens configurations. The sliding lens system allows the lens to fold flush the body of the camera.
The lens covers a range equivalent to 38mm-114mm on a 35mm camera, which I found not quite wide enough for my taste at minimum zoom.

Pentax Optio A20 Shake-Reduction
The A20 is among the first compacts from Pentax to include their CCD-shift camera shake reduction system. Depending on the conditions, I found the system gave between two and three stops advantage over shooting without the system activated. This means shots that would normally only be sharp at 1/60sec without shake reduction can be taken at shutter speeds as long as 1/8sec with the system activated.

Pentax Optio A20 Macro mode

The Pentax A20 will only alow you to get within 12cm of your subject, which is quite a distance, especially when compared to other similar cameras.

A 100% crop of the the shot to the left shows the level of detail captured.

Pentax Optio A20 Image quality
There are three different image quality levels on this camera - Fine, Normal and Basic. All images in this review were taken on Fine and at maximum resolution so that I could see what the camera is capable of producing using the typical settings.

	Above left - The auto white-balance performs well in all but the most challenging conditions. Above - The built-in flash provides bright and even illumination up to about five metres. Left - The A20 produces punchy images with plenty of contrast. Below - Skintones are reproduced well by the A20

The automatic metering struggled with this difficult overcast scene, adding 1/3EV extra exposure compensation, resulted in a more detail in the shadows.

Pentax Optio A20 Detail

This busy scene was taken using a tripod to determine the level of detail this camera can produce.

A 100% crop of the image shows that the extra pixels aren't wasted in this camera. Images are sharp and full of detail.

Compared to...

Casio Exilim EX-Z1000 at ISO100

Canon Powershot A700 at ISO100

I have chosen two cameras to compare to the A20, both comparable specifications. The Casio EX-Z1000 is a 10 megapixel compact digital camera in direct competition with the Pentax and the Canon A700 is a six megapixel camera with a larger zoom range and more creative controls.
The image produced by the A20 is clearly the most detailed of the three. Most fine detail is retained with good edge definition. The image from the Casio EX-Z1000 looks soft by comparison.

Pentax Optio A20 Noise test

The following images illustrate the amount of digital noise apparent at each ISO setting. The image to the right is the full image. The crops below are taken from where the green square is.
ISO64	ISO100
ISO200	ISO400
ISO800

Compared to...

Pentax Optio A20 at ISO400

Casio Exilim EX-Z1000 at ISO400

Canon Powershot A700 at ISO400

As pixel counts rise so does noise in most cases although the Optio A20 copes better than I'd expected at higher ISO sensitivities. If you compare the image from the A20 to that of the similarly specified Casio Exilim EX-Z1000 the difference is obvious. Noise levels from the A20 even compare well to the Canon Powershot A700, which has three million fewer pixels.

Pentax Optio A20 Verdict
Currently weighing in at a shade under £200, the Pentax Optio A20 represents good value for money due to the combination of great image quality, combined with an effective camera shake reduction system.

The SMC zoom lens fitted to the A20 is the perfect compliment for the high resolution 10 megapixel sensor, which yields great results at most ISO sensitivities when compared to cameras of equal specification. Even so, if many of your images will be taken in low-light, there may be other cameras that are better suited to you.

Those looking for a simple yet well specified compact digital camera will definitely wish to add this camera to their wish list, especially if large prints are to be produced.

In summary the positive points of the Pentax Optio A20 are:
High resolution.
Effective camera shake reduction system.
Great colour reproduction.

The negative points:
Although noise performance is good for a 10 megapixel compact, it is still put in the shade by many cameras with a lower pixel count.
Macro mode doesn't get particularly close.