Sony DSLR-A200 Optics
Sony A200 Optics
The Sony A200 features a bayonet lens mount, which accommodates a range of Sony and Konica Minolta lenses. The Sony A200 comes with a Sony 18-70mm f/3.5 kit lens. A separate kit comes with both the 18-70 and a 75-300mm f/4.6-5.6 telephoto zoom lens. A small button on the front of the camera releases the lens from its mount, so it can be turned and removed. The A200's CCD is smaller than a 35mm frame, so the angle of view at any given focal length will not be the same as on a 35mm camera. To find the approximate 35mm equivalent focal length, multiply the focal length of the lens by 1.5. (Thus, a 50mm lens will provide about the same view as a 75mm lens on a 35mm camera.)
The Sony A200 provides both manual and automatic focus control modes, set by the Focus Mode switch on the left side of the camera. You can select between Auto and Manual focus modes. The Function button provides access to additional AF Area and focus mode options. The Autofocus Mode option under the Function menu offers Single-shot AF, Automatic AF and Continuous AF settings. Single-shot sets focus with each half-press of the Shutter button, while Continuous mode is constantly adjusting the focus, whether the Shutter button is pressed or not. The Automatic setting will lock focus on a still subject or continually adjust focus on a moving subject, for as long as the Shutter button is halfway pressed.
Autofocus Area also has three options available through the Function menu: Wide, Spot, and Local (manual setting). The default option is a nine-point Wide Focus area, indicated by an array of dashes inset within four widely-spaced brackets in the viewfinder image. You can override the chosen AF mode by pressing the Spot AF / OK button in the center of the Multi-controller, which defaults to the more accurate center AF point (the latter indicated by a target box in the center of the viewfinder). Wide AF bases its focus on the most prominent subject detail in the portion of the image that falls within the AF brackets. Spot mode bases its focus on the very center of the frame, where the square target resides. The Local setting is Sony's terminology for a manual AF area selection, and lets you manually set the main AF point by using the Multi-controller to highlight one of the nine AF points. The active AF area is briefly illuminated in the viewfinder.
Sony didn't include a depth-of-field preview button on the A200, nor on any of the new consumer models announced early 2008. Admittedly, that feature is less useful with such a small viewfinder, but this factor might put off some macro and landscape photographers.
Sony A200 AF Assist
The Sony A200 uses its built-in flash head as a very bright AF-assist light for better focusing in dim lighting. This has the advantage that the light from the flash is very bright, but the downside is that you can only get AF assist when the flash head is raised. This is a real limitation for available-light photography, as the camera can expose at light levels below those it can focus at. (Although its low-light focusing ability is much better than average.) If the camera is fixed on a tripod, you can work around this limitation, but it's somewhat awkward: With the flash head up, half-press the shutter button to make the camera focus. Then switch the focus mode to manual focus, being careful not to touch the focus ring on the lens. Stow the flash head, and then take your picture. (But don't forget to switch back to AF mode for the rest of your shooting!)
Sony A200 Anti-Shake
The Sony A200 also employs Sony's Super SteadyShot anti-shake technology, which uses a highly sensitive angular rotation sensor and Smooth Impact Drive Mechanism (SIDM) to move the CCD assembly itself to counteract camera movement, rather than the more common approach of moving an optical element inside the lens. This body-based anti-shake approach is based on technology Sony acquired from Konica Minolta, but Sony claims that a more powerful processor in the A200 increases the system's effectiveness beyond that of similar systems in previous Konica Minolta SLR models. (Theoretically, a faster CPU could let the system respond to and compensate for higher-frequency vibrations.)
Sony claims that the Super SteadyShot anti-shake system in the A200 provides a 2 to 3.5-stop reduction in the blurring produced by camera shake. Translating that into real-world shutter speeds, a two-stop improvement means that a shutter speed of 1/30 second would give you the same resistance to blur from camera shake that a speed of 1/120 would without anti-shake. A 3.5-stop improvement would mean you could shoot as slow as 1/11 second and get the same results (blur-wise) as when shooting at 1/120 second unaided. Even the lower end of the specified range of effectiveness means a pretty significant improvement in one's ability to hand-hold long exposures.
When Super SteadyShot is activated, the SteadyShot scale on the right side of the viewfinder display indicates the degree of stabilization. A downside to Sony's body-based SteadyShot approach is that while you can see the results of stabilization on competing lens-based designs, you have only this scale to tell you how the A200's SteadyShot mechanism is doing. SteadyShot minimizes the effect of blurring caused by slight camera movement, which is more noticeable at long focal lengths.
Sony A200 Anti-Dust Technology
To help combat dust particles on the CCD from changing lenses, Sony included both an anti-static coating on the CCD filter and an anti-dust vibration to automatically shake the CCD each time the camera is shut off.
Sony A200 Optical Test Results
Below are the results of our optical tests on the Sony A200. We used the 18-70mm kit lens as the benchmark, since most people will buy and use the camera in this configuration.
Pretty good performance with the 18-70mm kit lens.
The Sony Alpha 200 comes with an 18-70mm kit lens, which is a fairly average optical zoom range of ~3.9x, but a little longer than most kit lenses. Details are reasonably sharp in the center of the frame at full wide-angle, with low levels of coma distortion but some noticeable blurring in the corners. Results at full telephoto are also quite good, though again, some blurring is noticeable in the corners of the frame.
A slightly larger macro area with the kit lens, with slightly soft details. Flash throttles down pretty well.
|Standard Macro with 18-70mm
|Macro with Flash|
The Sony A200 captured a slightly larger macro area with the standard 18-70mm kit lens, measuring 3.17 x 2.12 inches (81 x 54 millimeters). Details were soft throughout the frame. There was also some additional softening in the corners from the lens. (Most lenses have some softening in the corners at macro distances.) The A200's flash throttled down for the macro area pretty well, despite some slight overexposure.
Moderately-high barrel distortion with the 18-70mm kit lens, though low pincushion.
|Barrel distortion at 18mm is 0.8 percent|
|Pincushion at 70mm is less than 0.1 percent|
The Sony A200's 18-70mm kit lens produced about 0.8 percent barrel distortion at wide-angle, a little higher than average and noticeable in its images. At the telephoto end, the less than 0.1 percent pincushion distortion is fairly low. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).
High and bright at wide-angle, but low at telephoto with the 18-70mm kit lens.
|Wide: High and a little bright,
top left @ 200 percent
|Wide: Quite bright,
top right @ 200 percent
|Tele: Low and dull,
top left @200 percent
top right @200 percent
Chromatic aberration is high at the full wide-angle setting of the Sony A200's 18-70mm kit lens, showing about 15 pixels of bright coloration on either side of the target lines. Though it is bright, in some photographs it blends fairly well. At telephoto, distortion is much lower. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)
Fairly strong blurring in the corners of the frame at both zoom settings with the kit lens.
|Wide: Soft in the
corners (upper right).
|Wide: Sharp at center.|
|Tele: Also soft in the
corners (upper right)
|Tele: Sharp at center.|
The Sony A200's 18-70mm kit lens produced soft corners of the frame at full wide-angle and telephoto, noticeable in a few shots. The lens is also a little softer at telephoto than at wide angle.
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha DSLR-A200 Photo Gallery .
Note: For details, test results, and analysis of the many tests done with this camera, please click on the tabs at the beginning of the review or below.
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