Sony DSLR-A350 Optics
Sony A350 Optics
The Sony A350 features a bayonet lens mount, which accommodates a range of Sony and Konica Minolta lenses. The Sony A350 is sold body-only, but there are two kits, one that comes with a Sony 18-70mm f/3.5 kit lens, and another that comes with both the 18-70 and a 55-200mm f/4-5.6 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 Sony A350'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 A350 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 adjusts 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 A350 AF Assist
The Sony A350 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 A350 Anti-Shake
The Sony A350 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 A350 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 A350 provides a 2.5 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 A350's SteadyShot mechanism is doing. SteadyShot minimizes the effect of blurring caused by slight camera movement, which is more noticeable at long focal lengths. And since the Live View image is generated on a separate sensor, that mode also lacks an image stabilization preview.
Sony A350 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 A350 Optical Test Results
Below are the results of our optical tests on the Sony A350. We used the 18-70mm kit lens as the benchmark, since most people will buy and use the camera in this configuration.
Good performance with the 18-70mm kit lens, though with soft corners at telephoto.
The Sony Alpha 350 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 and slight blurring and chromatic aberration in the corners, but considering the 14.2-megapixel resolution, it's quite low. Results at full telephoto are also quite good, but there's more noticeable blurring in the corners of the frame.
A fairly large macro area with the kit lens, with slightly soft details. Flash throttles down pretty well.
|Standard Macro with
18-70mm Kit Lens
|Macro with Flash|
The Sony A350's kit lens captured a slightly large macro area with the standard 18-70mm kit lens, measuring 3.14 x 2.09 inches (80 x 53 millimeters). Details were soft throughout the frame. There was also some additional softening in the corners from the lens. (Most kit lenses have some softening in the corners at macro distances.) You'll get much better results with a dedicated macro lens. The Sony A350's flash throttled down for the macro area pretty well, despite minor overexposure which can probably be corrected with a touch of negative flash exposure compensation.
Moderate barrel distortion with the 18-70mm kit lens, though low pincushion.
|Barrel distortion at 18mm is 0.8 percent|
|Pincushion at 70mm is about 0.1 percent|
The Sony A350's 18-70mm kit lens produced about 0.8 percent barrel distortion at wide-angle. Though this is about average among the cameras we've tested, we still find it a little high to our eyes. At the telephoto end, the approximately 0.1 percent pincushion distortion is quite 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 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 fairly high and noticeable at the full wide-angle setting of the Sony A350's 18-70mm kit lens, showing 8-10 pixels of bright coloration on either side of the target lines. At full telephoto, this distortion is much fainter and not very evident in images. Again, though, the 14-megapixel sensor makes this chromatic aberration seem much more pronounced. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)
Moderate 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 (lower right)
|Tele: Fairly sharp at center.|
The Sony A350's 18-70mm kit lens produced moderately soft corners of the frame at full wide-angle and telephoto, noticeable in a few shots. The lens is also a little softer overall at telephoto than at wide angle. Keep in mind that sharpness usually improves once the lens is stopped down a few stops. (These shots are taken with the lens "wide open" at maximum aperture.)
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha DSLR-A350 Photo Gallery .