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- Sony Alpha SLT-A55V
- A new spin on the SLR, with a translucent mirror to let light through, so it can shoot and focus at the same time.
Sony SLT-A55 Digital Camera Review$899.99
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.
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.
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.
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.
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.
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.
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.
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.