Cameras

Sony SLT-A55 Digital Camera Review

A new spin on the SLR, with a translucent mirror to let light through, so it can shoot and focus at the same time.

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Introduction

The SLT-A55 is a new spin on the conventional SLR, with a translucent mirror that lets most light through, so the camera can shoot and focus at the same time. The result is a camera that has the advantages of an SLR (quick and flexible focusing and high quality images) but shoots much faster: 10 frames a second. And it has the image quality to justify the cost: we found that the images it took had good color and excellent overall sharpness, and the video looked great. However, the SLT-A55 also has the downsides of an SLR: it is a large, bulky camera that has a somewhat confusing menu system and only has a limited range of lenses available.

Design

Front

Front Tour Image

Back

Back Tour Image

Sides

Top

Top Tour Image

Bottom

Bottom Tour Image

In the Box

Box Photo

In addition to the camera, you get:

  • 3.5-5.6/18-55mm lens
  • USB cable
  • Neck strap
  • Battery charger
  • NP-FW50 1080mAh battery
  • Software CD

Not included is a HDMI cable or any analog A/V output cables. Any mini HDMI cable can be used for digital A/V output, and Sony offers an optional analog A/V out cable for showing images on an older standard definition TV.

Lens & Sensor

The SLT-A55 uses an Exmor APS CMOS filter, which measures 0.925 by 0.614 inches (25.5 by 15.6mm) and has a resolution of 16.7 megapixels. Of these, about 16.2 megapixels are used, with the rest being used for image stabilization. This CMOS chip uses RGB sensors, with the color filters being mounted onto the chip surface.

This sensor sits behind a translucent mirror, which is in a fixed position. Conventional SLRs work by moving the mirror out of the way when taking a photo, but the mirror of the A55 is translucent, so it lets most of the light through, but reflects a small amount into the viewfinder housing, where it is used to meter the scene and to focus. This means that the camera can focus and shoot images at the same time; it does not have to focus with the mirror down and then move it out of the way to take the photo.

Some users of this camera have reported a problem with this, seeing a ghost image caused by internal reflections from this mirror. We did see this on a few images (particularly those where bright objects were shot against dark backgrounds), but this was not a significant problem: the ghost image was much darker than the actual one, and were not visible in most shooting situations.

SONY-SLT-A55V-Mirror-diagram.jpg

Viewfinder

On the back of the A55 is the electronic viewfinder, which has a resolution of 1,440k pixels. Because it is electronic, it shows the image being captured by the image sensor, rather than the image through the lens that normal SLR cameras capture. We found the viewfinder to be comfortable to use, although it is a little difficult to see the entire image when wearing glasses: the edges of the image are blocked by the edge of the viewfinder unless you press your eye close to the viewfinder, which leads to smudges on the glasses. The image does break up somewhat with fast moving objects, if you pan the camera quickly or if you are shooting in very low light.

Diopter adjustment is available from a small dial on the right side of the viewfinder housing, and we found the viewfinder to be comfortable to use with spectacles. Below the viewfinder is an eye sensor, which switches from the screen to the viewfinder when it detects an approaching eye. However, it is also triggered by hands or fingers, and this is a little annoying when you are reaching around the camera body to press one of the buttons: the sensor is often triggered by the hand. This can be disabled, though, and a button on the top of the camera body can be used to switch between the viewfinder and the screen.

Display(s)

The LCD screen of the A55 is a large, bright 3-inch LCD with a 921k pixel resolution. This is very sharp and clear, and is visible in all but direct sunlight, which is where you would use the viewfinder instead of the screen. The screen is also articulated, with a hinge and pivot allowing you to flip the screen out and rotate it around. This allows the screen to be rotated so that it can be used for shooting with the camera held above, below or behind you. It is possible to also use this to shoot self-portraits, but the screen is somewhat obscured by the camera. Some Canon models use a side hinge, which is better suited to this, as the screen is less obscured by the camera body when it is rotated around to the side.

This rotating hinge also allows you to turn the screen around so that it can be folded flat against the camera body, protecting it from scratches and bumps. We were not able to test this to destruction, but we did find that the LCD screen and hinge feels tough: it is unlikely to break off or be otherwise damaged by anything other than extreme force.

Flash

There are two flash options with this camera: a small built-in flash, or attaching an external flash to the hot shoe on the top of the camera body. The built-in flash is a pop-up model located in the front of the viewfinder housing. It pops up when the small flash button is pressed: it does not pop up automatically. We found it to be reasonably powerful, penetrating total darkness out to a distance of about 11-12 feet, and having a pretty even flash pattern, although there is some vignetting at the edges of the frame at the widest angle setting of the kit lens: the edges of images taken there are noticeably darker than the middle. The flash sync speed is a pretty speedy 1/160 of a second: useful for capturing fast moving objects.

The other option is to attach an external flash to the camera through the hot shoe. This is a proprietary design: it will not work with standard hot she flash guns. Sony is the only company to make compatible models, and their HAL-F42AM flash costs $299.99. They do also offer a microphone that can plug into this port.

Flash Photo

The flash emitter pops up from the top of the body via a mechanical release.

Connectivity

The SLT-A55 offers a small number of ports, but the important ones are on offer, with a mini HDMI port, a multi-function USB and analog A/V output and a microphone input on the left rear side of the camera body. On the left front side is a single port for attaching an external GPS receiver. The camera does have an internal GPS receiver, but an external unit may have better sensitivity or be more accurate.

Battery

The power source of the A55 is a small 1080mAh battery that fits into a cavity in the camera grip. This battery (model NP-FW50) is recharged with the included charger: it cannot be recharged in the camera body. Sony quotes a battery life of 330 images with the viewfinder and 380 when using the screen, but this feels a little optimistic: we found that the battery did not typically last for more than a day of serious shooting. A spare battery would be a sound investment, and these cost about $60.

Battery Photo

Memory

The SLT-A55 can handle the Pro Duo and Pro-HG Duo variations of MemoryStick flash memory cards that Sony offers, but it can also work with SD, SDHC and the newer SDXC memory cards. Both types of card fit into the same slot next to the battery, below a latched cover.

Memory Photo

The K2000 accepts inexpensive, easy to find SD cards.

Media Photo

Image Quality

Sharpness

We found some issues with chromatic aberration when shooting with the kit lens: the images showed noticeable chromatic aberration at the edges of the frame across both the zoom and aperture range. Although it was noticeable across both ranges, it was most pronounced when the aperture was stopped down, which is pretty common with lenses like this. This aberration is caused by the lens, so it would be worth considering investing in a better lens if you want to avoid the characteristic color fringing caused by Chromatic Aberration. More on how we test sharpness.

Image Stabilization

The SLT-A55 includes Sony's usual SteadyShot Inside stabilization system, where the image sensor moves to compensate for camera shake. This differs from other manufacturers, who usually move part of the lens. The upside of this approach is that it works whatever lens you use, because the sensor is the part moving. On other cameras, the moving element has to be built into the lens.

We found that, when shooting with the 18-55mm kit lens, this system was pretty effective, especially with the high shake in our tests. This high shake simulates more extreme camera movements, such as shooting one-handed or while walking. We found that the images captured with SteadyShot turned on were sharper at all of the test shutter speeds in the high shake tests, but this was not the case with the low shake test, which simulates more subtle movements. In this case, having the SteadyShot turned on while shooting at speeds above 1/125 of a second were less sharp. At slower speeds, there was some improvement with it turned on, but it seems the system is more tuned to detecting larger camera movements.

Color

We found that the SLT-A55 captured pretty accurate color, although it struggled with some colors, such as the purples and magenta of our test chart. We also found that the colors were a little oversaturated in all of the color modes that the camera offers, with saturation ranging from 105 per cent up to 120 per cent, which produces almost cartoon-like results. More on how we test color.

To test color accuracy, we shoot our test chart in all of the color modes that the camera offers, and then determine which mode produces the most accurate color. For this camera, this was the Standard mode, but you should remember that color can be a rather subjective thing: some users might prefer the more saturated colors of another mode. You can see how the different modes affect the same colors from our chart in the next section of this review.

NOTE: Because of the way computer monitors reproduce colors, the images above do not exactly match the originals found on the chart or in the captured images. The chart should be used to judge the relative color shift, not the absolute captured colors.

Color Modes

The SLT-A55 offers 6 color modes: Standard, Sunset, Vivid, Portrait, Black & White and Landscape. The differences between these are mostly subtle, but do what you would expect, with Vivid and Sunset boosting the saturation to around 120 per cent and Portrait producing a more muted look than others. Examples from our color test chart for 5 of these modes are shown below.

White Balance

White balance is a critical factor for camera performance, as a camera has to be able to judge the white balance to show colors correctly. We found that the SLT-A55 did a pretty good job here, judging the white balance of various light sources on auto and correctly setting the white balance when using a custom setting. Like most cameras, the auto setting was slightly confused by incandescent lighting, though.

Automatic White Balance ()

To test the auto setting of the SLT-A55, we took photos of a colorcheck chart under three different types of light: incandescent, fluorescent and simulated daylight. This camera did a very decent job here, getting very close to spot on for the fluorescent and daylight. It was slightly off with the incandescent light, but most camera struggle with this light source.

Custom White Balance ()

We expect that using the custom white balance feature of a camera will produce more accurate results, because we give the camera a white card to work from. We found that the SLT-A55 was a little off here, though: both the incandescent and fluorescent light sources produced a significant error that could be visible in images.

Given this error, If getting a correct white balance is critical to you (such as for product photos, where the images have the match the subject), you might be better off shooting in RAW format and color correcting afterward in Photoshop.

White Balance Options

A good selection of white balance settings are on offer. As well as the full auto mode, there are 6 presets, all of which can be tweaked up or down to three steps (each step represents 10 Mired). You can also enter a color temperature directly, or use the custom setting to measure a white object. 3 memory spots are also available if you are able to visit a location before shooting and check the lighting. The color filter option allows you to set the white balance as a spot on a green/magenta compensation graph. And if you don't know what that means, you will probably never need it.

Long Exposure

Shooting in low light often involves using long exposures, and long exposures mean more time for electronic noise to gather in the sensor. This means noisy images, so we test how well the camera deals with this by shooting a number of images at different shutter speeds and examining the noise in them using Imatest. We found that the SLT-A55 had some issues here: although the colors in log exposure images were pretty constant, the noise in images with exposure times of more than 1 second was significant. We also found that enabling the long exposure noise reduction didn't make that much difference: in some cases, it seemed to make things a little worse. More on how we test long exposure.

When we look at the noise in images (see the chart below), we see that the noise in images rises as the exposure time increases, rising from 1.05 per cent to about 1.24 per cent at 30 seconds. The long exposure noise reduction didn't make much difference, and at some speeds it seemed to make things slightly worse.

Compared to other SLRs, the SLT-A55 didn't fare well: many other SLRs have lower, or more consistent, noise with long exposure levels. So, the SLT-A55 earns a lower noise score than all of our comparison cameras.

Noise Reduction

Looking at the individual color channels, we found that the same pattern was consistent, so there is no one color that is adding more to the noise. Only the luminance channel was slightly higher than the others, but not significantly so. More on how we test noise.

ISO Options

The SLT-A55 offers a very impressive ISO range, going from 100 up to 12800, all at the full resolution of the camera. If you really need to push it further, the SLT-A55 offers a special ISO expansion mode that takes 6 shots for each shutter press and combining the images together to form a single image. This can widen the effective ISO range to 100 to an incredible 25600. However, moving objects can confuse the camera: see our Sample Photos for an example. All of the images below were shot in the standard, single shot mode.

Dynamic Range

Dynamic range is a measure of how wide a range of shades a camera can capture: does it capture detail in shadows, or are they just black? We found that the SLT-A55 did a good job here, capturing a wide dynamic range at the lower ISO settings which would allow it to capture a good level of both shadow and highlight detail. More on how we test dynamic range.

The dynamic range of the camera falls significantly as the ISO is increased, so it is important to keep the ISO as low as possible to get the best image quality. However, the dynamic range of this camera remained wider than other comparable cameras across the range. We also found that the SLT-A55 could capture a slightly wider range than other cameras at the lowest ISO settings: it captures just under a stop more than the Panasonic G2.

Sony also offers a special shooting mode called D-Range optimizer, which they claim uses special image processing techniques to enhance the dynamic range. This mode does not expand the dynamic range of the camera, but can bring out shadow detail in images by tweaking the gamma of the image. There are 5 levels of D-Range optimization: you can see examples in the Sample Photos section of the review.

The SLT-A55 also offers an Auto HDR mode, which increases the dynamic range of photos by taking three images at different exposures and combining them together to form a single image. This HDR (High Dynamic Range) technique can expand the dynamic range that a camera can capture, and we found that it produced quite attractive results. You can read more about this mode in the controls section of this review, and see examples in the Sample Photos section.

Noise Reduction

Looking at the individual color channels, we found that the same pattern was consistent, so there is no one color that is adding more to the noise. Only the luminance channel was slightly higher than the others, but not significantly so. More on how we test noise.

ISO Options

The SLT-A55 offers a very impressive ISO range, going from 100 up to 12800, all at the full resolution of the camera. If you really need to push it further, the SLT-A55 offers a special ISO expansion mode that takes 6 shots for each shutter press and combining the images together to form a single image. This can widen the effective ISO range to 100 to an incredible 25600. However, moving objects can confuse the camera: see our Sample Photos for an example. All of the images below were shot in the standard, single shot mode.

Focus Performance

Long Exposure

Shooting in low light often involves using long exposures, and long exposures mean more time for electronic noise to gather in the sensor. This means noisy images, so we test how well the camera deals with this by shooting a number of images at different shutter speeds and examining the noise in them using Imatest. We found that the SLT-A55 had some issues here: although the colors in log exposure images were pretty constant, the noise in images with exposure times of more than 1 second was significant. We also found that enabling the long exposure noise reduction didn't make that much difference: in some cases, it seemed to make things a little worse. More on how we test long exposure.

When we look at the noise in images (see the chart below), we see that the noise in images rises as the exposure time increases, rising from 1.05 per cent to about 1.24 per cent at 30 seconds. The long exposure noise reduction didn't make much difference, and at some speeds it seemed to make things slightly worse.

Compared to other SLRs, the SLT-A55 didn't fare well: many other SLRs have lower, or more consistent, noise with long exposure levels. So, the SLT-A55 earns a lower noise score than all of our comparison cameras.

Video: Low Light Sensitivity

The SLT-A55V needed 11 lux of light to hit 50 IRE on our waveform monitor. In a strange coincidence, this was the same amount of light required by the other three cameras we compared it to. This makes it rather simple to compare the A55V's low light sensitivity to the competition.

Chromatic Aberration

The images shot by this camera were generally pretty sharp, although the images were somewhat softer when the aperture was stopped down all the way to the f/22 or f/36 maximum of the lens. At more open apertures, the images were pretty sharp across the frame, with only a slight falloff at the edges. From our tests, the sharpest images are captured when this lens is in the middle of the aperture range at about f/13 to f/14.

In the widest zoom setting, the best performance from this lens comes in the middle of the aperture range: the images captured at f/13 are sharper and more clearly defined than the others.

In the middle of the zoom range, once again, the best performance comes from the middle aperture setting, although the widest aperture is also pretty good. The smallest aperture is extremely soft.

At the longest zoom setting that this camera offers, the sharpness is acceptable at the widest and mid apertures, but the image gets extremely soft at the smallest aperture of f/36. One important thing to remember here is that this test is very dependent on the lens, and it seems that the 18-55mm zoom lens that Sony bundles with this camera is not particularly great. We don't test with other lenses, but it seems that the camera is capable of much better performance with a higher quality lens.

Distortion

The 18-55mm SAM lens that comes with the SLT-A55 is biased more towards the wide end of the zoom range, and this seems to have something of a price: the lens introduces a lot of distortion at the wide angle setting: 3.29 per cent barrel distortion, where straight lines become curved inwards towards the center of the image. This distortion was much less at the middle of the zoom range and was barely noticeable at the 55mm setting, though, so you should stick with this end of the zoom if you want straight lines and undistorted faces in your photos.

Motion

The Sony SLT-A55V records Full HD video with a 60i frame rate, which is what you commonly see on consumer camcorders (including Sony models). The camera also has a 1440 x 1080 MP4 record mode that uses a 30p frame rate, but we didn't see too much different between the motion quality of the two record settings. More on how CamcorderInfo tests motion.

We like the way the A55V records motion, and the camera's results in our motion test were similar to the Sony NEX-5. The SLT-A55V did capture a smoother video image, however, and there was slightly less artifacting and interference than what we saw on the NEX-5. Our main complaint is that there's no 24p mode on the SLT-A55V.

The Canon Rebel T2i captured some of the best motion video we've seen from a DSLR camera. It records using 24p or 30p frame rates, but it does not have a 60i or 60p mode. So, this means it essentially offers the opposite frame rate options than the Sony SLT-A55V.

The Nikon D5000 is behind the times in terms of its motion capturing capability. In our testing, the camera recorded choppy motion video with terrible interference and jagged lines. The camera also had a very bad rolling shutter problem, although this is a common issue with video-capable DSLRs. The Nikon D5000 records video using a 24p frame rate.

As we said before, the NEX-5 captured motion in a similar manner to the Sony SLT-A55V, but we liked what we saw from the A55V a bit more. The NEX-5 had more artifacting, its video looked a bit choppier, and there was more blur noticeable in the rotating pinwheels in our test.

Video Sharpness

With its Full HD (1920 x 1080) recording capability, we expected the Sony SLT-A55V to put up a strong showing in this test. The camera did not disappoint, as it measured a horizontal sharpness of 700 lw/ph and a vertical sharpness of 725 lw/ph. These numbers were the best out of the other video-capable DSLRs we compared it to, although we have seen better sharpness scores from consumer HD camcorders. More on how CamcorderInfo tests video sharpness.

Low Light Sensitivity

The SLT-A55V needed 11 lux of light to hit 50 IRE on our waveform monitor. In a strange coincidence, this was the same amount of light required by the other three cameras we compared it to. This makes it rather simple to compare the A55V's low light sensitivity to the competition.

Usability

Buttons & Dials

The SLT-A55 has no shortage of dials and buttons on the body: we counted 19 buttons and switches plus the control dial on the camera body. That is a somewhat bewildering selection for the novice, but it does put the options to hand for more experienced users. We do find some of the choices a little unusual, though; the presence of a dedicated button for the D-Range setting, but no secondary control dial for controlling aperture in full manual mode seems like an odd set of priorities.

The menu of the SLT-A55 is divided into two parts: the function menu that appears when you press the function button and the main menu that is accessed with, appropriately enough, the menu button.

The function menu is designed for on the fly changes, such as changing ISO or auto focus mode quickly. There are 12 options in total, arranged in groups of 6 down the left and right sides of the camera screen. You navigate by using the directional pad, then select an option by pressing the center button.

The screen for the function then opens, with the options presented in a list that you can scroll up and down through and select the option by pressing the center key. A text explanation of the function is also shown on the right side of the screen. Some of the major functions (ISO, display, white balance, AF and drive mode) are also available more directly from buttons on the camera body. When these are used, the camera jumps straight to the control screen, skipping the function menu. The function menu works pretty well, but it can involve some button mashing by having to scroll up and down to reach the option you need.

The main menu contains all of the options from the function menu and a lot more, arranged in a tabbed structure, with just a single screen of options per tab. Again, this involves quite a lot of scrolling around to find specific options, especially as you can't from the bottom of the list of options to the top or vice versa.

Instruction Manual

Our review model was supplied without documentation, but we were able to review a PDF version of the instruction manual, which covers both the A33 and the A55. We found this manual to be well written and generally easy to use, with plenty of illustrations. Some aspects of the camera are not discussed in any great detail: the image stabilization of the camera only gets a single page.

Handling

Although the SLT-A55 is smaller than most SLR cameras, it is larger than most interchangeable lens cameras. The body measures 4.8 bu 3.62 by 3.3 inches, which makes it a touch smaller than the Canon T2i, but substantially larger than Sony's own NEX-5. That is because of the hybrid nature of this camera, which still includes the mirror of an SLR, but one that does not move, so it needs fewer parts surrounding it. The camera feels natural in the hand, with the wide, deep grip providing plenty to hold onto and the textured rubber surface providing a firm grip with sweaty hands. The index finger falls naturally onto the shutter and power control, and can easily reach around to the control dial on the front of the camera body.

Handling Photo 1

The thumb also falls naturally into an indentation on the back of the camera, but it can also comfortably reach the movie shutter, exposure compensation and AEL (Auto Exposure Lock) buttons. The latter is especially important, as it is often used when shooting in low light with spot metering: you center the subject, meter, then use the AEL button to lock the exposure while framing the shot.

With the other hand bracing the camera body, the thumb can also reach for the Fn button, which provides quick access to the shooting control. With this combination, you can control all of the shooting features of the camera without taking your eye away from the viewfinder: an important factor if you are trying to shoot quickly and efficiently.

Handling Photo 2
Handling Photo 3

Buttons & Dials

The SLT-A55 has no shortage of dials and buttons on the body: we counted 19 buttons and switches plus the control dial on the camera body. That is a somewhat bewildering selection for the novice, but it does put the options to hand for more experienced users. We do find some of the choices a little unusual, though; the presence of a dedicated button for the D-Range setting, but no secondary control dial for controlling aperture in full manual mode seems like an odd set of priorities.

Buttons Photo 1
Buttons Photo 2

Display(s)

The LCD screen of the A55 is a large, bright 3-inch LCD with a 921k pixel resolution. This is very sharp and clear, and is visible in all but direct sunlight, which is where you would use the viewfinder instead of the screen. The screen is also articulated, with a hinge and pivot allowing you to flip the screen out and rotate it around. This allows the screen to be rotated so that it can be used for shooting with the camera held above, below or behind you. It is possible to also use this to shoot self-portraits, but the screen is somewhat obscured by the camera. Some Canon models use a side hinge, which is better suited to this, as the screen is less obscured by the camera body when it is rotated around to the side.

This rotating hinge also allows you to turn the screen around so that it can be folded flat against the camera body, protecting it from scratches and bumps. We were not able to test this to destruction, but we did find that the LCD screen and hinge feels tough: it is unlikely to break off or be otherwise damaged by anything other than extreme force.

Viewfinder

On the back of the A55 is the electronic viewfinder, which has a resolution of 1,440k pixels. Because it is electronic, it shows the image being captured by the image sensor, rather than the image through the lens that normal SLR cameras capture. We found the viewfinder to be comfortable to use, although it is a little difficult to see the entire image when wearing glasses: the edges of the image are blocked by the edge of the viewfinder unless you press your eye close to the viewfinder, which leads to smudges on the glasses. The image does break up somewhat with fast moving objects, if you pan the camera quickly or if you are shooting in very low light.

Diopter adjustment is available from a small dial on the right side of the viewfinder housing, and we found the viewfinder to be comfortable to use with spectacles. Below the viewfinder is an eye sensor, which switches from the screen to the viewfinder when it detects an approaching eye. However, it is also triggered by hands or fingers, and this is a little annoying when you are reaching around the camera body to press one of the buttons: the sensor is often triggered by the hand. This can be disabled, though, and a button on the top of the camera body can be used to switch between the viewfinder and the screen.

Image Stabilization

The SLT-A55 includes Sony's usual SteadyShot Inside stabilization system, where the image sensor moves to compensate for camera shake. This differs from other manufacturers, who usually move part of the lens. The upside of this approach is that it works whatever lens you use, because the sensor is the part moving. On other cameras, the moving element has to be built into the lens.

We found that, when shooting with the 18-55mm kit lens, this system was pretty effective, especially with the high shake in our tests. This high shake simulates more extreme camera movements, such as shooting one-handed or while walking. We found that the images captured with SteadyShot turned on were sharper at all of the test shutter speeds in the high shake tests, but this was not the case with the low shake test, which simulates more subtle movements. In this case, having the SteadyShot turned on while shooting at speeds above 1/125 of a second were less sharp. At slower speeds, there was some improvement with it turned on, but it seems the system is more tuned to detecting larger camera movements.

Shooting Modes

The SLT-A55 has a 10-position mode dial on the top left of the camera body, which offers the following modes: Auto, Auto+, Program, Aperture Priority, Shutter Priority, Manual, Fast Burst, Panorama, Scene (see below), and No Flash.

Focus

The SLT-A55 tries to include the best of both worlds when it comes to focusing, combining the flexibility of the SLR (which has dedicated focus sensors) with the speed of mirrorless cameras (which use the image sensor to focus). The SLT-A55 has a fixed mirror which is translucent: it lets most of the light through to the image sensor, but bounces some up to the 15 dedicated focus sensors in the viewfinder housing. The theory is that this arrangement allows the camera to focus and shoot at the same time, because the camera does not have to focus then wait for the mirror to move out of the way to shoot: the mirror remains in place. This theory is most borne out in practice: the camera focuses quickly, and there is much less delay between pressing the shutter and the camera taking the shot. It also means that the camera can focus and take shots at the same time, which makes the cameras burst mode both faster and more accurate, as the camera can keep focusing while it is shooting.

There are three options for how these 15 AF spots are used: Wide allows the camera to choose, while Spot uses the center group of 7 and Local allows you to choose an individual spot. We found that the SLT-A55 focused quickly in most situations, although it did swim a bit in low light, focusing back and forth to look for the focus point. The center group of focus points are the best ones to use in low light: they are cross-type sensors that work better in low light, and we found that the camera had some issues focusing on off-center objects in low light settings.

Recording Options

The SLT-A55 offers a wide selection of options for image size and compression when you include the panorama modes on offer. There are only three sizes for standard, still photos, though: L, M and S. You do get the choice of two aspect ratios: 3:2 and 16:9.

In addition, there are two options for the JPEG compression (Fine and Standard), plus the ability to capture RAW files and RAW and JPEG files simultaneously. The last two options slow the camera down considerably, though, and use a lot of storage space for images.

Other Controls

The SLT-A55 offers a number of special shooting modes, most of which are useful (such as Auto HDR and Panorama), but the 3D panorama mode feels like a poorly executed gimmick.

Dynamic Range Optimizer (DRO)

In this mode, the camera processes a single captured image to show a wider dynamic range by tweaking the gamma curve of the image processing. Although this can bring out shadow details, it does not widen the dynamic range of the sensor or the captured image. For examples of images shot in this mode, see our sample photos section of this review.

Auto HDR

The camera takes 3 images at different exposure settings, then processes them down into one image, producing an image with more dynamic range than any single image the camera can capture. This can be set to auto, or 1, 2, 3, 4, 5, or 6 stop differences between the images. For examples of this mode, see our sample photos section.

Multi-frame noise reduction

In this special ISO setting, the camera takes 3 images and then combines the results, with the theory being that the combined images will have lower noise than one single shot. It also allows for higher ISO settings: up to 25600. In practice, it does seem to make a significant difference, with less noise appearing in images, but it only works with still or slow-moving objects: if anything moves in the frame (or the camera moves), the image becomes blurred. Samples are shown in the Sample Photo section of this review.

Hand-Held Twilight

This mode has been seen on several of Sonys point and shoot cameras. It works by taking 6 images, then combining the sharpest parts of each into a single image. Again, it works well with static objects, but movement produces blurs.

Panorama

The SLT-A55 can take panoramic images by taking several images as the camera is panned and then combining them into a single, larger image. This differs from the one-shot panorama that many Sony point and shoot cameras can produce: in this, the camera shoots the panorama as a single image, but the A55 shoots a lot of images and combines them. Options are available for the direction of pan (left, right, up and down), as well as the size (small or wide). Examples can be seen on the Sample Photos page of panoramas shot in this mode.

3D Panorama

The SLT-A55 can also shoot 3D panoramas, where the camera tries to create a 3D panorama image by capturing separate images as you pan the camera. The process is awkward: we typically found that it required several attempts to get the shooting process right, with the camera often complaining that we were moving too fast or too slow. The results were not that impressive, either: there were obvious glitches in the images we took where the camera had incorrectly joined the images together, and the 3D look of the images was not consistent. You also need a 3D HDTV to view the images, and there is no way to preview the results on the camera screen. Basically, it feels like a poorly executed gimmick rather than a useful feature.

Speed and Timing

The SLT-A55 also offers a good amount of control over the burst shooting, providing two levels of burst: a 10 fps mode that can shoot a burst of up to 39 images (in JPEG format: using RAW+JPEG limits this to 20 shots), and a 6 fps mode that can shoot continuously up to the capacity of the card. One quirk of the burst mode is that, while the camera automatically adjusts the shutter speed to compensate for changing lighting while shooting, the camera can only control aperture if you put the auto focus mode to the AF-S setting, so it only focuses once at the start of the burst of images. What this means in practice is that you are forced to choose between having the camera continually focusing or having control over the aperture for no adequately explained reason, which limits the usefulness of the mode. Using the 10fps mode also slows the camera down a lot after shooting, as it has to take time to write the images out to the memory card. It is still possible to take images, but only intermittently and in a seemingly random pattern. So, although the 10fps burst mode works as advertised, it does have a few caveats that make it less flexible than we had hoped.

Because the mirror stays in place when shooting, the the SLT-A55 is a speedy shooter: we measured it at an impressive 10 frames a second (fps), which is exactly what Sony claims. This does come with a caveat, though: it can only manage this speed for a burst of 39 or so frames. After this, the speed slows to between 4 and 6 frames per second, which is heavily dependent on the speed of the memory card in use. The camera also offers a continuous shooting mode, which we measured at about 6 fps, but which could be sustained for as long as their is space on the memory card. Our review unit had no problem maintaining this speed with out test card (a Sandisk 4GB SDHC card).

This speed puts it ahead of the pack when compared with other SLRs: it is significantly faster than all of our comparison models. The only conventional SLRs to get close to this speed are some professional models, such as the Canon 7D and the Nikon D300s, both of which can manage about 7 to 8 frames a second, but which cost much more than the SLT-A55.

The usual options are available for taking delayed images: a 2 and 10 second delay, plus a smile detect mode that only takes the photo when it detects a smile.

In addition, the SLT-A55 supports an optional IR remote, which can be used to take photos. No pricing is currently available for this remote control.

Focus Speed

The SLT-A55 tries to include the best of both worlds when it comes to focusing, combining the flexibility of the SLR (which has dedicated focus sensors) with the speed of mirrorless cameras (which use the image sensor to focus). The SLT-A55 has a fixed mirror which is translucent: it lets most of the light through to the image sensor, but bounces some up to the 15 dedicated focus sensors in the viewfinder housing. The theory is that this arrangement allows the camera to focus and shoot at the same time, because the camera does not have to focus then wait for the mirror to move out of the way to shoot: the mirror remains in place. This theory is most borne out in practice: the camera focuses quickly, and there is much less delay between pressing the shutter and the camera taking the shot. It also means that the camera can focus and take shots at the same time, which makes the cameras burst mode both faster and more accurate, as the camera can keep focusing while it is shooting.

There are three options for how these 15 AF spots are used: Wide allows the camera to choose, while Spot uses the center group of 7 and Local allows you to choose an individual spot. We found that the SLT-A55 focused quickly in most situations, although it did swim a bit in low light, focusing back and forth to look for the focus point. The center group of focus points are the best ones to use in low light: they are cross-type sensors that work better in low light, and we found that the camera had some issues focusing on off-center objects in low light settings.

Features

Other Features

GPS

The SLT-A55V includes a built-in GPS receiver, which can be used to geo-tag images, with a longitude and latitude being added to the EXIF data. We found that this GPS receiver did work well, but it did often take a significant time to get a location fix. Bars by the side of the GPS icon on the screen indicate if the camera is getting a fix, but the camera seems to use the old location if it cannot update with a new one: several of the test shots taken in our Cambridge, MA studio were tagged as being taken in the UK because the camera was not able to update its location indoors, so it kept using the old one. If you frequently turn the camera on and off between shots, this could mean that many of your images are not properly tagged. Sony also offers a model without the GPS feature: the SLT-A55.

Recording Options

The Sony SLT-A55V has two compression options for recording video: AVCHD and MP4. The AVCHD mode captures Full HD video at a 1920 x 1080 resolution and a 17Mbps bitrate, which are similar to the specs you'll find on Sony's consumer camcorders. The MP4 mode has two quality settings: a 1440 x 1080 HD mode and a 640 x 480 standard definition setting.

The advantage of having both AVCHD and MP4 compression options is that it gives you more versiatility when recording video. AVCHD clips can be difficult to work with on a computer, but they look great when viewed on a high definition television. On the other hand, MP4 clips are easy to play back on a computer and upload to the internet, but they won't look as good on a TV (especially considering the MP4 modes on the A55V use lower bitrates to record video). Find out how the performed in our video image quality test./r:link_to_content

Video Controls

Auto Controls

Since the SLT-A55V doesn't really have any manual controls in video mode, you must rely in the camera's automatic settings for everything except focus and exposure. This lack of aperture and shutter speed control will probably not please Sony fans who are looking for a more versatile DSLR to record video, but it does make things simple.

The A55V does expose video quite well during recording and its autofocus mechanism is one of the best we've seen from a video-capable DSLR. The focus doesn't work quite as quickly as what you get on a consumer camcorder, but it is close.

Zoom

Zoom on the SLT-A55V is entirely determined by the kind of lens you have attached to the camera. The kit lens we did our testing with was a traditional 18-55mm lens, which is close to a 3x optical zoom. Zoom is adjusted by rotating the lens ring.

Focus

Focus is an area where the SLT-A55V has an advantage over other video-capable DSLRs, most of which do not have the ability to autofocus during video recording. Wit Sony's Translucent Mirror Technology, however, the camera can perform a continual autofocus during recording (or before recording) without the need to press or hold a button.

The focus is fairly quick, but it is a bit noisy. If you want to record clean audio, you may want to stay away from the live autofocus feature, or use an external mic with the camera (and hold it far enough away so it doesn't pick up the clicks and motor noise caused by the autofocus mechanism). Of course, you can also manually focus using the camera's outermost lens ring.

Exposure Controls

Of the controls listed above, only exposure can be set manually in video mode on the Sony SLT-A55V. You can set the exposure by rotating the control dial on the front-right of the camera after pressing the +/- exposure button.

Confusingly, you can adjust aperture and shutter speed on the camera, but once you press the record button the camera reverts to automatic settings (for everything except exposure).

Other Controls

Just like aperture and shutter speed, you cannot adjust the ISO manually in video mode. If you select a specific ISO before beginning your video recording the setting will revert to auto ISO after you press the record button.

The "Creative Style" color settings on the SLT-A55V can all be used in video mode, as can the camera's various white balance presets and manual settings.

Audio Features

The SLT-A55V has a built-in stereo mic and a 3.5mm mini mic jack for connecting an external mic. Since the built-in mic is tiny and located on the top of the camera, we don't recommend using it if you want to capture clean audio. It will pick up a lot of extraneous noise like the camera's autofocus system or the adjustment dial if you choose to adjust exposure during recording. You can even turn audio recording off in the camera's menu if you don't want to deal with that function.

Mic Photo

In the Box

Box Photo

In addition to the camera, you get:

  • 3.5-5.6/18-55mm lens
  • USB cable
  • Neck strap
  • Battery charger
  • NP-FW50 1080mAh battery
  • Software CD

Not included is a HDMI cable or any analog A/V output cables. Any mini HDMI cable can be used for digital A/V output, and Sony offers an optional analog A/V out cable for showing images on an older standard definition TV.

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