Sony Alpha SLT-A33
Sony A33 Flash
The Sony A33 features a built-in, pop-up flash, which operates in either Auto, Fill-Flash, Slow-sync, Rear-sync, Wireless, and Flash-off modes. To release the flash from its compartment, press the button on the left side of the electronic viewfinder / flash housing. Close it again by pushing the flash head back down.
The Flash mode is changed from the Function screen. In Auto flash mode (available only in the camera's Auto or Scene Selection modes), the camera automatically determines when to fire the flash based on the existing lighting, and will pop-up the flash automatically. In Fill-Flash mode, the flash fires with every exposure, regardless of lighting conditions. Slow-sync mode fires the flash for foreground fill exposure, while allowing the background to burn in. The Rear Flash Sync mode fires the flash at the end of the shutter time, rather than the beginning. If you have moving objects in the scene with lights, such as a passing car, this will produce a sharp image of your subject, with a "motion trail" following behind it when shooting at slower shutter speeds. The flash is off when Flash Off mode is selected, or when the flash is down in non Auto exposure mode.
Flash exposure compensation can be set via the Function menu, within a +/- 2-stop range, in 1/3-stop increments. Flash metering options are ADI, which considers focus distance as well as pre-flash light metering, and pre-flash TTL, which considers only exposure metering of the pre-flash. The flash metering mode is selected through screen 2 of the Record menu.
The A33's built-in flash has a Guide Number (GN) of 10 meters or 32.8 feet at ISO 100. That's a bit less than typical consumer SLRs we've tested, which average about 12 meters. Maximum flash sync speed is 1/160 second. High Speed Sync (HSS) shooting with shutter speeds up to 1/4,000s is available with Sony HVL-F58AM and HVL-F42AM external flash units.
A Red-Eye Reduction option is available through screen 1 of the Custom menu. When Red-Eye reduction is enabled, the camera will fire a few low-power flash pulses before it actually snaps the picture, to make the pupils of your subjects' eyes contract.
The A33 also has a top-mounted, proprietary hot shoe for attaching an external flash unit. The shoe design and contact arrangement are set up for Sony's own dedicated flash units.
The Wireless mode lets the Sony A33 work with compatible remote flash units with wireless capability, specifically the Sony HVL-F58AM and HVL-F42AM. Four separate control channels are available for wireless operation, to allow multiple photographers to work wirelessly in the same area without interfering with each other. You're limited to a single external flash unit vs the 3 groups that you can control with Sony's higher-end models, but it still opens a lot of creative possibilities, when the flash doesn't have to be attached to your camera. Operating in Wireless mode with a compatible external flash unit, the Sony A33's flash exposure compensation adjustment can adjust the intensity of the external flash remotely, once the camera and flash unit have been initially synched to each other.
Flash Test Results
Coverage and Range
A somewhat weak flash with uneven coverage at wide-angle. Our standard shot required average exposure compensation.
Coverage. Flash coverage was quite uneven at wide-angle (18mm), leaving very dark corners in our flash coverage test image. Uneven coverage at wide-angle isn't unusual, though. Coverage was much more uniform at telephoto (55mm).
Exposure. The Sony A33 required +0.7 EV flash exposure compensation for our Indoor Portrait test scene, which is average for this shot. The camera's Slow-Sync flash mode produced bright, even results with +0.3 EV compensation, though with a stronger pinkish-orange cast from the room lighting.
ISO 100 Range. With the 18-55mm kit lens, flash exposure started out quite dim at 6 feet at wide-angle but brightened up at 7 feet, and remained bright until 10 or 11 feet where it started to decrease gradually as distance increased. At full telephoto, flash exposure started out bright at 6 feet, but decreased in brightness from then on. Flash exposure was also somewhat inconsistent at full telephoto, with 15 feet being brighter than 14 feet, etc.
|Manufacturer-Specified Flash Range|
Manufacturer Specified Flash Test. The Sony SLT-A33's built in flash is rated with a Guide Number of 10m at ISO 100. That works out to about 9.4 feet at f/3.5 and 5.9 feet at f/5.6, the maximum apertures of the kit zoom lens. In the shots above, the Alpha SLT-A33 performs as Sony says it will, producing good exposures at the rated distances with its ISO set to 100 at both wide-angle and telephoto, though results are actually a little too bright (by about 0.25 EV) at full wide-angle. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.
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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.