Sony Cyber-shot DSC-TX7

Resolution (11.39)

We were also favorably impressed with the performance of the TX7 in our tests on the resolution of the images it captures. We found that the images were sharp and had only slight distortion across the 4x zoom range that this camera can manage. The only issue that we saw was a small amount of chromatic aberration in the middle of the zoom range. More on how we test resolution.

Distortion (10.28)

We found that the images that this camera captured had very low distortion at the mid and telephoto points of the zoom range, with both showing less than 0.5 per cent distortion, which is pretty much invisible. There was a bit more at the widest point of the zoom range, though; we saw about 1.5 per cent distortion, which is just enough to be visible: long thin objects like lamp posts and walls will look slightly distorted. Below are examples of the distortion from our test chart.

Distortion Examples
Wide (4.43mm): 1.46% Pincushion Distortion
Mid (9.0mm): 0.42% Pincushion Distortion
Tele (17.7mm): 0.55% Pincushion Distortion

Sharpness (14.07)

We found that the images captured by the TX7 were pretty sharp for the most part, although the sharpness did fall off somewhat at the edge of the frame in all of our test images, as you can see in the examples below. This slight drop in sharpness was present at all points on the zoom range, but was particularly pronounced at the wide and telephoto ends of the zoom range, where it became quite significant.

Chromatic Aberration (6.37)

The other thing that we noticed was that there was a significant amount of chromatic aberration (CA) at the widest end of the zoom range on the edges of the frame. The amount of CA that we saw at the mid and telephoto zoom points was low, but there was a lot at the widest zoom point, which shows in the wide crops on the charts below and our sample photos as a distinct color fringe to sharp edges.

Quality & Size Options (6.08)

The TX7 offers only a limited amount of control over the size and quality of the images that it takes: you can’t control the quality of the compression, and there are just 5 options for the image size. When the camera is in easy mode, the choices are even fewer: you get options for large (10 megapixel) or small (5 megapixel) images.

Image Stabilization (8.12)

The TX7 pulls all the stops out when it comes to image stabilization: as well as an optical image stabilization system (which moves an element of the lens to compensate for movement) there is a special mode called Anti-Motion Blur. What this does is to take 6 images in quick succession, then combines them to create a single, sharper image. In the same situation, other cameras would have to take a longer exposure, with more possible issues of blurring. The Ant-Motion Blur seems to work very well: when we compared images taken in the program mode of the camera against those taken in the Anti-Motion blur mode, the latter were significantly sharper and had less blurring. There is a minor downside, though; the images don’t appear on the screen for several seconds (as the camera has to process them), and you can’t take images quickly. This might be an issue if you are trying to capture a soccer game or other fast-moving sport. More on how we test image stabilization.

Stabilization Comparisons
Sony DSC-TX7	Sony DSC-T900	Samsung TL225	Canon S90
Stabilization Off
Stabilization On