Digital Camera Review

Digital Camera Review

Sony’s top-end Cyber-shot model, the DSC-F828, is an 8.0 megapixel, four color channel (Red + Green + Blue + Emerald) CCD camera with a unique design and a host of professional features (live histogram, multi formats and burst modes, etc.) that brings Sony into the prosumer SLR market. The Sony DSC-F828 is quite an improvement over the previous model, the DSC-F717, which was very much a consumer camera. Priced at just under US $1,000, the DSC-F828 may be a good option for the Sonyphile ready to replace their older Sony digital still camera. Equipped with a 7x optical zoom Carl Zeiss Vario-Sonnar T* multi-coated lens with a 7.1-51mm focal range, in addition to a 2/3-inch 8.0 megapixel CCD, the Sony DSC-F828 is poised to make its mark in the professional imaging world.
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Color (7.48)
We test the color accuracy of the camera using Imatest Imaging Software and a GretagMacbeth color chart. The test gauges the actual color produced by the camera against the ideal color. In the chart below, the outer square is the color produced by the camera. The center square is the camera's produced color, corrected by the software, while the interior vertical rectangle is the ideal color.

Imatest software allows us to analyze how much the camera differs from true color representation. In the following chart the squares represent ideal colors and the circles represent what the camera produces. The farther a circle is from its tethered square, the less accurate the camera is in reproducing that particular color. If the circle is farther towards the perimeter of the chart, the produced color is over-saturated. When the circle is closer to the center of the chart, the produced color is duller and more diffused than it should be.  

 

The Sony F828 received a mean saturation score of 104.4%. This is a measure of the colors' vibrancy, reflecting how much the hues are intensified. While many people enjoy more pastel-like images, there is something to be said about color accuracy - it is hard to replicate and the F828 does it better than most. The Sony F828 surpasses Canon's digital SLR, the EOS Rebel, in color saturation but falls just short of the Nikon D70, perhaps the most accurate color imager on the consumer market at the time of this writing. This speaks loud for Sony, placing them in an elite category and shows that not all digital cameras prefer over-saturating their images.

The Sony F828 received an overall color score of 7.48. This is a good score but is not quite as impressive as some less expensive cameras on the market. If you study the above chart, you will see that while the F828 does not over-saturate its color tones, many of them are a bit dull. Many of the blue, green and orange values are slightly muted and do not jump out as much as they should. The red tones are over-saturated; however, this should be expected to some extent as many cameras emphasize red and orange hues to get more color in skin tones. Additionally, it does not appear that many of the F828's colors are as spot on as one would hope them to be. While none of the colors are too far off the ideal, I would say all in all that the color on the F828 is not up to the level of its peers. As an 8 megapixel, $1000 camera, the stakes are high and I would expect more accuracy from a camera in this category.

Still Life
The below image is our standard still life which we photograph with every digital still camera:


Clicking on the above image will open a full resolution version in a new window (CAUTION: The linked image is very large)

Resolution / Sharpness (5.43)
The Sony F828 provides a clean image; however, for an 8 megapixel imager, it does fall a bit short of expectations. The F828 received a real resolution score of 5.43 megapixels. This is roughly 68% of its advertised megapixel count. These tests are conducted using Imatest software and a resolution chart, taken under fixed lighting conditions. We take a series of exposures on the camera’s optimal settings and select the highest score to report, as this is the best we could get the camera to perform. These scores are contrasted with the manufacturer’s resolution count, providing a percentage score of the manufacturer’s claim. In general, a score of 80% or higher is a good performing camera, while anything over 90% is excellent. Therefore, the Sony F828 is a bit disappointing particularly for an 8 megapixel camera, as the camera will only provide resolution equivalent to an excellent performing 6 megapixel camera, yet its price may be over $400 more.

Noise - Auto ISO (6.37)
The Sony DSC-F828 is marketed to a more advanced user, offering manual flexibility in most imaging facets. However, as far as noise performance goes, the F828 seems a stronger automatic imager. While the ability to control ISO is crucial to many users, from the tests we conducted, the Sony F828 faces problems in higher ISO ratings that other 8 megapixel cameras seem to avoid. This camera produces images that are closer to many 5 and 6 megapixel imagers and should be viewed accordingly. Often the boxed description and megapixel count is a far cry from the actual capabilities of a camera and it appears that this is the case with the F828. I would not say this camera is incapable of producing strong images; however, like many 5 megapixel point-and-shoot camera, once the ISO rating is pushed above 200, there is serious quality depletion and increased noise throughout the images.

Noise - Manual ISO (5.37)
For cameras which allow you to manually set the ISO, we test the noise produced by the camera at each setting using Imatest Imaging Software. Below is a graph of the noise produced by the Sony DSC-F828. On the horizontal X axis are the ISO scores, and on the vertical Y axis are the noise levels:

Looking at the graph, the noise growth is directly related to increased ISO. The problem is that these are all quite large noise values and all are very bad. The Sony DSC-F828 produces a lot of noise. To understand the overall noise performance, we run a regression analysis on each noise and ISO score. We then turn this equation into the overall score. This number reflects the entirety of noise and can be viewed on the chart as it relates to the various ISO settings.

Speed/Timing
Start-up to First Shot (8.57)
The Sony DSC-F828 did pretty well on start-up to first shot time. Averaging the scores for shots at the macro and telephoto levels, the first shot is taken approximately 1.43 seconds after the camera is turned on.

Shot to Shot Time (5.54)
The shot to shot time on the F828 is a little less impressive. It took on average 4.46 seconds (at JPEG Fine) to record an image and shoot another. One factor of some concern is the auto review that users cannot interrupt. For example, when the shutter is depressed, the image is stored to the memory stick or CF card, then displayed. If a user wants to take multiple pictures, she cannot. Switching the camera into the somewhat-slow digital burst mode is the only alternative.

Shutter to Shot Time (7.82)
The shutter lag time was pretty decent as well, measuring approximately 0.59 seconds between pressing the shutter and taking a picture.

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