Sony Alpha A100 Digital SLR Review

Sony have a colourful product history behind them. Once they dominated the portable music market with the first ever personal cassette player, which you and I would know as the Walkman. Other high-end electronics such as CD and DVD players, laptops and TVs have all been given the Sony treatment, and their line of Cybershot digital compact cameras is amongst one of the world's most successful brands. No wonder so much speculation surrounds Sony's first foray into digital SLR territory. In this review Gary Wolstenholme takes a look at the new Alpha A100 to find out if iit's the 'Playstation' of the photography world.

Specification

• Super SteadyShot CCD-shift camera-shake reduction.
• 9-point AF.
• ISO100 to ISO1600 sensitivity range.
• 2.5inch LCD screen.
• 10.2 megapixels.
• Eye-start AF.
• Shutter speed range of 1/4000sec - 30sec and bulb.
• 1/160sec flash synch speed.
• 40-segment honeycomb pattern meter.
• Exposure compensation +/- 2EV.
• Built-in flash. Guide No 12(ISO100/m).
• Pentamirror viewfinder with approximately 95% field of view.
• Continuous shooting up to 3fps.
• Continuous shooting buffer unlimited for Jpeg, six frames for RAW.
• RRP - £599.99 body only, or £699.99 with the Sony 18-70mm lens.

Build and handling First impressions of the A100's build quality are not good. The plastic construction has a lightweight 'toy-like' feel to it, not a cheap toy though. This feeling is especially apparent on the CompactFlash door, built-in flash and battery chamber door. Things aren't all bad though. The deep-contoured finger grip has a textured finish that feels secure to hold, and the body feels well-balanced, despite the cameras lightweight design. The size and weight makes the A100 an ideal travel camera, when the idea of lugging a solid professional body around all day isn't all that appealling.

Display screens and viewfinder The viewfinder in the A100 is large and bright enough to meet most people's requirements. Focus confirmation is made easy by the clarity of the matte screen. A 2.5inch LCD screen on the rear displays essential exposure information whilst shooting. It has a great anti-reflective coating on the surface which can be clearly seen from an angle. This makes reviewing pictures in bright light much easier than on cameras with a shiny protective layer. Images displayed on the screen are bright and clear, and of high resolution.

Menu and controls Two dials on top of the A100 provide control over most photographic settings. The dial to the right contains six preset scene programs, a point & shoot automatic mode and the usual four creative manual modes. The other dial has a function button in the centre which allows adjustments such as the metering mode, flash exposure compensation, focusing mode, ISO sensitivity, white-balance, D-Range optimisation and colour settings. Other controls include the exposure compensation and drive mode buttons, located around the exposure mode dial. The shutter button and adjustment dial fall directly under my index finger. I would have preferred a little more space between these controls to allow for quicker exposure adjustment whilst taking pictures. As it stands, I have to take my finger off the shutter release to change exposure settings. The in-camera menu is exactly the same clearly laid-out system as found on previous Dynax digital SLRs. It seems as though Sony decided that an, 'if it ain't broke, don't fix it' approach was required when designing the camera.

Battery An 'M' series lithium-ion battery provides power for the A100, although the battery supplied is an 'InfoLithium' one like found in Sony's range of camcorders and compact digital cameras, the A100 cannot read the InfoLithium chip to work out exactly how much battery power is remaining. A blue clip inside the chamber holds the battery firmly in place, even if the battery door is accidentally opened.

Lens system As a result of Sony's acquisition of Minolta's photographic assets, the A100 uses the same lens mount previously found on Minolta Dynax cameras. This means that a huge range of lenses are available either new, or second-hand. A new range of Carl-Zeiss lenses have been announced along with the existing line-up of Minolta lenses, which are now re-badged with Sony livery. A .pdf leaflet containing the full range of Sony alpha lenses can be viewed here.

Flash system The Dynax lens mount wasn't the only aspect of Minolta SLRs inherited by Sony. The A100 uses the same proprietary Dynax hotshoe, which means only dedicated Sony, and Minolta Dynax flashguns and accessories can be attached. Sony will soon be releasing two new flashgun models, along with a range of flash accessories which can be seen on the Sony DSLR website.

A white wall shot using the on-board flash at 18mm, adjusted in levels to illustrate flash coverage. Fall-off towards the edges is quite smooth and is not easily noticeable in normal circumstances.

Memory card
The Alpha A100 uses a Compact Flash memory card which fits into the slot on the side. The following are write speeds for various quality settings using a Sandisk Extreme III card.

Quality setting	Time taken to write to card
10.2 megapixel RAW	4.1secs
10.2 megapixel Jpeg fine	2.6secs
10.2 megapixel Jpeg standard	2.4secs

I also timed the delay between shots with this camera in the single shot mode. I measured this by taking five shots in quick succession and working out the average delay.

Quality setting	Shot-to-shot delay
10.2 megapixel RAW	2.84secs
10.2 megapixel Jpeg fine	1.22secs
10.2 megapixel Jpeg standard	0.94secs

The buffer in the A100 does a fine job of soaking up all the information recorded by the 10.2 megapixel sensor. In fact, the times I recorded are faster than many six megapixels cameras of the same class.

Shooting
The 9-point autofocus system is quick and responsive, aided by the eye-start system which sets the camera into action as you bring your eye to the viewfinder. The furthest AF points from the centre are aligned with the classic 'rule-of-thirds' areas of the frame, which makes creative composition of off-centre subjects simple. Each AF point glows red when selected and they're clear enough to see in both bright and dark conditions.

Above - The auto white balance performs well under most conditions. Left - The multi-segment meter has coped well with this backlit white building, keeping as much detail from the foreground as possible.

Super SteadyShot
CCD-shift Anti-Shake was first introduced by Minolta in their Dynax 7D digital SLR. Now Sony have inherited this technology and re-named it Super SteadyShot. Sony also use this mechanism to shake loose dust particles from the sensor when the camera is switched off.

0.4sec exposure at 35mm without Super SteadyShot

0.4sec at 35mm with Super SteadyShot

Sony claim that their CCD-shift system will allow you to achieve sharp shots with a shutter speed up to 3.5stops slower than normal. This will depend entirely on the shooting conditions and the lens used, a gauge in the viewfinder display also informs you how much the camera is moving, making it easier to judge whether your shot will be sharp in the end.

D-Range Optimiser
The D-range optimiser function is designed to adjust the exposure and contrast of an image to counter the effects of high-contrast shooting conditions, as you would normally use fill-in flash. To test its effectiveness, I took pictures of a flower silhouetted against the a partially overcast sky.

DR off	DR off plus fill-in flash
DR Standard	DR Advanced

For comparison, I also included a shot taken with a pop of fill-flash. As you can see from the examples, this yields the best result of all. DR standard visibly lightens the whole image, which results in a detail-free sky. DR advanced lightens the flower slightly, while keeping some detail in the sky. None of the two modes were capable of evening the contrast levels sufficiently for a satisfactory result.

Anti-dust measures
Sony have modified the CCD-shift system in the Alpha so that it will vibrate when the camera is switched off. By doing this, the CCD-shift mechansm should behave similarly to Olympus' Supersonic Wave filter, dislodging dust particles that are adhered to the sensors surface. Sony have also added a specially formulated anti-static coating to minimise any static build-up that would hold dust in it's place.

The images below are the results of testing the effectiveness of the system. For testing purposes, I allowed dust to build up on the sensor by opening the shutter for long periods using the bulb setting until the amount of specks were substantial enough. The shutter was opened for over two hours in total, which would be the equivalent of many lens changes under normal circumstances. I then switched the camera on and off five times. If you move your mouse pointer over the left-hand image, you will see the effect this had.

Hover over this image to see the effect five cleaning cycles has on a dusty sensor

The camera was powered down with the battery removed and left overnight to allow any static build-up to dissapate. To see the effect of five more cleaning cycles, hover your pointer over the image above.

After seeing that the dust hadn't budged an inch after five cycles, I concluded that static build-up on the sensor's surface must be responsible for holding the particles in place. To make sure this wasn't the case, I removed the battery from the camera and left it overnight so I could repeat the process in the morning. The image on the right-hand side is the result of repeating five cleaning cycles in the morning, moving your mouse-over the image will show the results of this test.

Unfortunately, vibrating the sensor still hasn't budged most of the dust. If you move your move pointer over the right-hand image repeatedly, you'll see that one of the larger particles has rotated slightly, but that's it I'm afraid.

It's a shame this test ended in disappointment, I really wanted this seemingly good idea to be effective, but as you can see from the results, it's far from it.

Compared to...
Olympus are the only other manufacturer who appear to have taken the dust issue seriously by implementing their SuperSonic Wave Filter technology in all their SLR cameras. I performed the same test as I did with the Sony Alpha A100 on an Olympus E-300 for comparison.

Dusty sensor before cleaning with the Supersonic wave filter

Olympus E-330 sensor after five cleaning cycles

After five cleaning cycles the SuperSonic Wave filter appears to be much more effective than Sony's solution as it has removed much of the dust from the sensor surface.

Image quality

All images for this review were taken at maximum resolution using the fine JPEG compression setting. There are several different compression levels and resolution settings including RAW to choose from allowing you to select the setting most appropriate for your needs.
	Above - The Sony 18-70mm kit lens focuses close for a zoom of this range, making it useful for general close-ups. Left - Images are contrasty and well saturated using the default settings.

Digital noise

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.
ISO100	ISO200
ISO400	ISO800
ISO1600

Both ISO100 and ISO200 deliver clean images with little sign of noise. Noise is more apparent at ISO400 and ISO800, but the levels are still very well controlled. By ISO1600, noise levels have increased to noticeable levels, with a coarse multi-coloured grain.

Compared to...

Sony Alpha A100 at ISO1600

Pentax K100D at ISO1600

Canon EOS 5D at ISO1600

At ISO1600, the A100 fairs less well than the opposition. The Pentax K100D takes full advantage of its larger pixels to deliver a cleaner image than produced by the Sony. The Canon EOS 5D out-classes both cameras, but then it should do being around three times the price.

Detail comparison

This busy scene was taken using a tripod to determine the level of detail this camera can produce.	Sony Alpha A100 set at ISO100 using a Sony 18-70mm lens set at 18mm and f/16.
Pentax K100D set at ISO200 using a Pentax DA 18-55mm lens set at 18mm and f/16.	Olympus E-330 set at ISO100 using the Zuiko 14-45mm lens set at 14mm and f/16.

The 10.2 megapixel sensor in the A100 produces noticably sharper, detail-rich images than other cameras in its class. I was especially surprised to see the difference between the Olympus and the Sony, as the Olympus' two megapixel deficit shouldn't really make that much difference.

DxOMark provides objective, independent, RAW-based image quality performance data for lenses and digital cameras to help you select the best equipment to meet your photographic needs. Visit the DxOMark website for tests performed on the Sony Alpha A100.

Verdict
Sony's first venture into the digital SLR marketplace may bear many hallmarks inherited from their acquisition of Minolta's photographic assets, but credit is due to Sony for the addition of an excellent 10.2 megapixel sensor that produces images of quality beyond those of the competition, at a tempting price point.

Other aspects of the camera are not so impressive. The D-Range optimiser doesn't seem to deliver the results that are promised, and the plastic build is disappointing when compared to some competing cameras. They have also made their mark with a seemingly simple modification of the Super SteadyShot system that should shake dust loose from the sensor each time the camera is switched off. Unfortunately this failed to perform as I'd hoped in testing.

The quality of images produced, coupled with the range of features packed into a compact SLR body certainly make Sony's début worth serious consideration.

In summary the positive points of the Sony Alpha A100 are:
Image quality up to ISO800
Super SteadyShot
Responsiveness
Backwards compatible with Minolta Dynax lenses

The negative points:
Plastic build
D-Range Optimiser doesn't produce results as promised

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