The 24.6-megapixel Alpha A900 is Sony's first full-frame digital SLR and is aimed at professional photographers, especially studio-based pros looking for the ultimate in high resolution.
It’s hard to believe that just over three years ago there wasn’t a single DSLR bearing Sony’s name. Yet now, its Alpha system has proved itself just as credible as its competition, and with the A900 the company’s aim to have a DSLR line spanning the entire market has been fulfilled.
Of course, entering such a market is not a decision to be made lightly, and in fairness Sony’s position was a somewhat advantageous one right from the outset. The company already had a history of semiconductor manufacture before it took control of Konica Minolta’s imaging arm, and already had its foot in both compact and camcorder markets, too. Furthermore, its huge marketing muscle goes some way to explaining the Alpha range’s meteoric rise, with Sony’s transparency about its ambitions making the A900 a talking point for the past two years.
Naturally, Sony’s competitors have been making their own advances too, yet at least on paper the A900 still manages to hold a number of trump cards, not least in its resolution. Perhaps more important, the A900 provides the strongest indication yet as to what part Sony will play in the ever-changing DSLR landscape. So, will the A900 be the camera that finally ends the dominance of Canon and Nikon?
At the heart of the A900 is Sony’s Exmor sensor, scant details of which were made public at the start of the year. It’s a full-frame CMOS chip, with a total count of 25.7MP and an effective output of 24.6MP, and it contains over 6,000 parallel analogue to digital (A/D) converters. This, Sony claims, allows data to be converted quickly to resist noise and other interference, with noise reduction applied on-chip both before and after the signal has been converted. The sensor has been designed to match the capabilities of Sony’s Alpha range of lenses, in particular its G series and those manufacturers under the Carl Zeiss brand.
Images from the camera measure 6048 x 4032 pixels at their maximum resolution, with an average JPEG weighing in at just under 70MB when opened. In addition to the three levels of JPEG compression, the camera supports Raw and compressed Raw (cRaw) formats; this latter setting reduces files by around a third in size, with a supposedly negligible effect on image quality. So much so, in fact, that Sony’s intention is to make it the primary Raw recording option in its future models.
The sensor’s design has also taken into account the image-stabilising Super SteadyShot function. It follows the same sensor-shift principle we’ve seen before, though the system has been redesigned to cater for the larger surface area of the sensor. This makes it the first full-frame image-stabilisation system, claimed to offer up to four steps of usable shutter speeds slower than would be otherwise possible. In comparison with Sony’s previous Super SteadyShot systems, it’s also claimed to be 1.5x more powerful and able to function 1.3x faster, with the vibrating mechanism also serving to combat the effects of dust.
The camera offers a standard sensitivity range of ISO 200-3200, expandable to equivalent settings of ISO 100 and 6400. Noise reduction is optional for exposures longer than a second, while images shot at or above ISO 1600 carry additional options for high, normal or low noise reduction. Driving this and all other operating and processing functions is a take on the Bionz processing technology we’ve seen before. Notably the camera now contains two processors, which apply further dual-step noise-reducing algorithms as part of their image processing. The processor also allows for a sustained burst rate of 5fps at the full 24.6MP resolution, for up to 105 Fine JPEG files or 12 Raw files, or 10 Raw+JPEG files at either full or compressed Raw settings.
As with Nikon’s D700 and D3 models, the A900 offers support for both ‘full-frame’ and Sony’s DT range of lenses, the latter specifically designed for cropped sensors. Any mounted DT optic decreases the effective resolution to 11MP while increasing the focal length magnification factor to 1.5x, though Sony has made it clear that it cannot guarantee exposure when DT lenses are used in certain situations. The reason for this is that the edges of the lens sit inside the sensor’s full-frame area, obscuring the peripheries which can influence metering.
Predictably, we see some features carried on from the A700, and the metering pattern is one of these; this comprises a 40-segment honeycomb pattern and both average and spot options. Dynamic Range Optimisation has also been included, with Standard and Auto Advanced settings, in addition to a further advanced option that allows you to fine-tune optimisation to one of five levels. Meanwhile, the focusing module sports nine standard points and 10 AF assist points, with its central point being the only one of the dual-axis ‘cross’ variety. This is said to enhance accuracy when shooting at apertures of f/2.8 or wider.
The area where Sony has made considerable noise is the A900’s pentaprism viewfinder. The aim was to surpass the performance of the Minolta Dynax 9, and not only does Sony claim to have achieved this, but to have bettered the performance of its competitors, too. Figures provided by Sony claim that the finder exhibits a 0.2 – 0.4EV brightness advantage over competing models, and 20% less distortion than the Dynax 9. This is aided by Sony having redesigned the condenser lens at the prism’s base and the eyepiece optics, while multi-layered, anti-reflective coatings have been applied to help minimise ghosting. What results is a viewfinder with an approximate coverage of 100% and a magnification factor of 0.74x.
Sony’s approach to live view has been a curious one, in that it has developed the most efficient and fluid version we’ve yet seen but only included it on two of its DSLRs. The live view-less A700 was released at a time when every other manufacturer was pushing the technology, and once again the A900 does the same – the logic behind this being that live view isn’t as great a priority as other features. Had its current live view system been implemented in the a900 this would have compromised the performance of the viewfinder (given the extra sensor in the camera’s prism), so essentially we have that impressive viewfinder in its place.
Just as impressive is the camera’s body. Sony has said that making the A900 lightweight was one of its objectives, and at a body-only weight of 850g it’s done well to fulfil this aim. Looking at the camera’s construction, a frame consisting of aluminium has been complemented with magnesium alloy panels around the front, back and top, while a polycarbonate mirror box has been reinforced with carbon fibres. The mirror unit itself has also seen a revised construction, using a ‘parallel-link’ mechanism to adjust the angle at which the mirror is lifted. By doing so, the mirror lifts over two pivots rather than swinging from one, and, given its size, it’s able to travel more efficiently.
One of the more interesting features we see debuting in the Alpha range is the Intelligent Preview function; this allows you to take a preview image, before varying exposure, dynamic range and white balance settings and seeing their effects upon the image. Four small histograms – one for each colour channel and one for exposure – are provided alongside, and once the desired settings have been selected the camera then sets these for you to take the final image. In fairness, this isn’t the first time we’ve seen such a concept, though how comprehensive it is sets it apart from other implementations.
Flash and Battery
There’s no built-in flash, though compatible units include Sony’s innovative HVL-58AM, which features a Quick Shift Bounce system ideal for portrait-oriented shooting. Thanks to its rotating head it provides the same concentration of light whether the camera is held in either a portrait or landscape orientation, and is even capable of adjusting its own white balance. Other units include the cheaper HVL-F42AM flashgun, ring and twin-light options, and third-party units from Sigma, Metz and Sunpak.
Finally, the camera’s InfoLithium battery is claimed to offer up to 880 shots from a single charge, with its charged percentage constantly displayed on the camera’s LCD screen. Considering that the camera has two processors to deal with this is quite an achievement, though the lack of both live view and a video facility helps conserve power.
Similarities to A700
Cosmetically, the A900 treads much the same path as its A700 sibling, and again not straying too far from the Konica Minolta template. In fact, you could almost mistake the back of the Dynax 7D for that of the A900, given how little Sony has deviated from the former’s control and button arrangement. Standard operational controls – such as menu, display and playback – sit along the left of the LCD screen, while the metering mode lever, power switch and Super SteadyShot button are both similarly placed and orientated to previous models. The changes Sony has made from the A700 are slight at best, such as with the design of the thumb rest and labelling of functions, though the camera is slightly wider and its connective ports now encroach slightly further onto the rear from the left-hand side.
The jewel in the crown is the viewfinder, and being the largest we’ve seen yet on an Alpha model we’d expect it to make an impression on the top plate. Bucking the smoother and more organic contours of similar models, the prism sits proudly in a pyramid-like fashion, with defined edges and a peak at its apex. Next to this we see a small LCD screen, which displays basic exposure information, while the other side plays host to a mode dial, offering basic exposure modes and three customisable settings.
How this all translates to handling is a varied matter. The camera isn’t exactly heavy, but feels no less solid than its competitors, while all buttons are clearly defined and access to main functions is either direct or pretty close. The A900’s connective port covers are more solid than the slightly flimsy ones of the Nikon D700, and it’s hard not to appreciate how extensively the body has been rubberised in order to provide a secure hold.
The grip has, however, been contoured to fit only two fingers, which can place more strain than usual on your little finger after a day’s shooting. We also found the camera not entirely accommodating to left-eye shooting, spectacle wearers, in that to see both the entire viewfinder and the exposure information along its base requires one to press one’s face right up against the back of the viewfinder, which puts the nose in close contact with the rear command wheel, thereby increasing the chances of accidentally changing the autofocus point while using the Local AF mode.
The first few times we turned the camera on, the Auto Rotate function would display the graphic user interface at the wrong orientation. For example, we would be holding the camera horizontally but down towards the ground, while the display would be vertically aligned. The camera would need a good shake for it to adjust itself – fortunately this feature can be disabled via the menu.
Sony doesn’t quote what memory card it used to achieve its burst depth figures, but using a Lexar 8GB UDMA card with a write speed of 300x, simultaneous Raw and JPEG images, as well as cRaw and JPEG images, each beat their targets by a frame to make 11. Extra Fine images also surpassed their 11-frame limit to an average of 35, but the biggest surprise came with Fine JPEG files. Despite a quoted frame depth of 105 shots, we achieved bursts of 251, 216, 586 and 153 frames. The final attempt fell just six frames short of the full capacity of the card, notching up a staggering 1,366 frames with no slowdown.
We used a range of lenses to compare any differences in focus, and as we may expect from compact, fixed-focal-length lenses, the 50mm f/1.4 did a fantastic job. In low light at its widest aperture it did well to focus quickly, and in better light its speed was hard to fault. I was surprised by how similar a performance the slightly quieter 16-80mm Zeiss lens exhibited, particularly with no SSM high-speed motor to drive its focus. So, focusing is generally good, though anyone wishing to upgrade this would have to pay a fair price for one of Sony’s SSM lenses. Only four Sony lenses with the technology currently exist, in addition to two Zeiss-branded optics and a few older Minolta High Speed (HS) telephoto lenses. As with Olympus, this can be attributed to how long Sony has been developing lenses in comparison with other manufacturers, though more SSM lenses have been promised in the near future.
Sony’s ambivalence about using DT optics is perhaps equally an issue. While we didn’t see any grave exposure errors using the DT 16-80mm Zeiss lens, the viewfinder’s method of marking out the DT area seems very half-hearted. There are just four thin corners, which can be hard to see against dark or more intricate subject matter, and worse still, they don’t light up at any point during focusing to assist you. For this reason, shooting at night with a DT lens can prove difficult, and I’d say this poor support is perhaps one of the biggest disappointments about the A900, particularly if you’ve already invested in any of Sony’s DT lenses and see the a900 as a potential upgrade. Aside from this, the viewfinder is hard to fault; it’s large, clear and bright, and exactly what you want it to be.
One feature we did use often was the Intelligent Preview function, given how practical we found it. It provides the easiest method of fine-tuning key settings; for instance, fine-tuning exposure can be easily and quickly done, as is the case with the Dynamic Range Optimisation, and also of finding which combination of the two provides the best result. The white balance presets, though, may only be compared easily with those directly either side of them. The Auto setting, for example, is five steps away from the fluorescent preset, meaning you need to make a mental picture of one before turning all the way to the other and figuring out which is the most appropriate. We should clarify that we’re poking holes in the finest system of its kind and that in most situations it’s a perfectly valid and useful function.
We anticipate this feature will work its way down to future consumer models, as it serves more as a good learning tool rather than something the post-processing pro will need to call upon too often. We also hope this transcendence applies to the A900’s high-resolution LCD screen which is as a perfect match for the model’s other high-end credentials. Now that we’ve seen a fair few models with this LCD resolution, only the most entry-level of DSLRs will be able to get away with anything less. Our only niggle regarding how it performs is its drop in contrast in bright, outdoor conditions, though this is a criticism you could level at most DSLRs.
Raw and JPEG
JPEGs on their standard settings were about as soft as expected, and could generally do with a little boost in sharpness. Thankfully, Sony supplies its Raw-processing Image Data Converter software with the A900, which is fully featured with all main processing options.
Despite the odd over and underexposed image, the metering system kept within the margin of error we would expect, and studio tests showed the camera’s midtone to be neither too bright or dark. We used the Dynamic Range Optimiser on a number of occasions, and with seven separate options to choose from, what setting you use can make quite a difference to the final image. The process does give rise to noise and noisereduction artefacts in areas that have been ‘lifted’, though; for which reason the function seems a little redundant on a ‘pro’ model such as this one, when a more sensible option would be either to shoot Raw or at the very least to bracket exposures.
Anyone expecting the same sort of high-ISO performance the Nikon D700 displays will be disappointed, but with a sensor that’s twice as populated this probably should come as no surprise. Images shot at ISO 200 are detailed, though there’s a very slight granularity and some chroma noise in blue skies, while midtones at ISO 400 also reveal a little chroma noise. Despite a coarse texture and a fair helping of chroma noise, images do still remain fairly detailed and relatively sharp at higher sensitivities, though Raw files are noticeably sharper. The high-sensitivity noise-reduction settings do a good job of filtering out the coarsest chroma noise, but only the most conservative ‘Low’ option strikes a good balance between noise reduction and detail retention.
Colour and White Balance
The Auto White Balance system worked well, with just a few errors on its part. These seemed to bias towards producing slightly warm images. Mixed lighting is always a struggle for Auto White Balance systems, and one instance where we found inconsistencies was when shooting under a mixture of daylight and fluorescent light. In comparison with the closest preset (Daylight) the camera produced a very warm, magenta-toned cast. We also found this issue when shooting outside in sunny conditions, but for the most part it got it right.
Sharpness and Detail
With a little processing, Raw and JPEG files exhibit good detail and respond well to sharpening. Noise reduction is sometimes necessary before sharpening, as sharpening itself can make noise more pronounced.
Value for Money
Value for Money
Currently, the A900’s two rivals are Canon’s 5D Mark II and Nikon’s D700. If comparing specifications, we see that the Sony has the edge in terms of its resolution and viewfinder coverage, but loses out on its sensitivity range, live view, and, with the 5D Mark II, a video facility. We imagine many purists will side with Sony on the live view issue, and we can’t imagine that omitting a video facility would alienate too many buyers either. You could, however, argue that much of the A900’s ‘core’ specifications – such as focusing, metering and sensitivity – are barely different from the A700, a model a third of its price. So, whether the camera is good value or not depends on whether you need the improvements Sony has made over the A700, and don’t mind what its feature set has left out.
Camera Layout Chart
It should come as no surprise that the A900 is a solidly built DSLR, capable of producing highly detailed images. From a practical consideration, its resolution and the Carl Zeiss optics currently available make it a perfect match for landscape and studio photographers, as well as anyone else needing high-resolution files. With its full-frame sensor, those still holding on to their Minolta lenses will also regain their wide angles. Hats off to Sony for the grip and flash options it provides for use with the model, too. These really go above and beyond the norm, and if they are indicative of how committed Sony remains for the professional then we can?t wait to see what comes next. But just as it?s clear what applications the A900 does suit, we?d be more hesitant to recommend it for anything that requires shooting at high sensitivities. With such a populated sensor we see a slight disadvantage when it comes to controlling noise, and this, together with its resolution, narrows the market for whom the A900 would be the ideal camera. We make this point not to demean the camera?s performance, but more to highlight how better suited it is to certain applications than others.
Yet despite this, we do admire what Sony has done with the A900. It blends a capable feature set with highly detailed images, adding a further dimension to the full-frame DSLR market.
9 with 10 AF assist points
View product shots of the Sony Alpha a900
View sample photos of the Sony Alpha a900
1/250sec (without SSS)
2500 – 9900K
Adobe RGB, sRGB
Electronically controlled, vertical traverse, focal plane type
Single shot, automatic, continuous, direct manual focus, manual
+/- 3EV in 1/3 or ½ increments
850g (exc. card, batt or accessories)
156.3 x 116.9 x 81.9mm
NP FM-500H Li-ion battery
USB 2.0 Hi-speed
Memory stick, CF, Microdrive
Fixed, eye-level pentaprism
Single, continuous lo, continuous hi, mirror lock, self timer, remote
Auto, six presets
200-3200 (exp 100-6400)
PASM, Auto, 3 x Custom
40-segment honeycomb pattern, multi-segment, average, spot
1/8000 – 30sec, bulb
Raw, cRaw, JPEG, Raw and JPEG
3in TFT LCD, 921,600 dots
6048 x 4032 pixels
Exmor full-frame CMOS type,
35.9 x 24.0mm, 25.7MP total, 24.6MP effective