Archive for October, 2010:
Recently I’ve been leaning into the big DSLR world. Now the big question is which one do I buy? My gut reaction was the Canon 550d/T2i, or the GH2. Then someone told me about the Sony SLT-A55V, quite the amazing camera if I do say so myself. I’ve yet to purchase it, but I’m writing a review based on other reviews I’ve read.
Sony’s latest interchangeable lens cameras, the SLT Alpha A33 and A55 represent a significant technological milestone – not just for Sony but for the enthusiast camera market as a whole.
Sony A55 – key specifications
- 16.2MP (effective) APS HD CMOS sensor
- Fixed, pellicle-type semi-translucent mirror
- Maximum ISO 12,800 (with a quasi-ISO 25,600 ‘Multi-frame NR’ option)
- 15-point phase-detection AF array with 3 cross-type AF points
- Electronic viewfinder with 1.15 million dot resolution
- Built-in GPS
- Electronic level in EVF/LCD with pitch/roll indicator
- Dual-purpose Memory Stick/SD card slot
- 10fps continuous shooting rate
- 1080p AVCHD movie mode with continuous AF
- Articulated 3in ‘TruBlack’ LCD with 912k dots
- socket for external microphone
The mirror in the A55 is semi-transparent. According to Sony, it allows approximately 70% of the light that strikes it straight through to the 16.2MP CMOS imaging sensor. The remaining proportion is reflected upwards to a large 15-point phase detection AF array. This equates to a roughly 1/3 EV reduction in light transmission for live view/image capture but means the AF sensor is always receiving light.This isn’t an entirely new idea – fixed, semi-transparent mirrors have been built into SLRs before, but the system in the A33 and A55 is a major new development. What makes the A33 and A55 unique is that they can maintain phase-detection AF at all times, even during an exposure.
They manage this by removing the optical viewfinder entirely and only having to direct light to the phase-detection AF sensor array. For packaging reasons this has been moved from its conventional position at the base of the camera’s mirror box, to its roof. Roughly 30% of the light that strikes the main mirror is reflected upwards, onto the AF sensor array. Meanwhile, in the absense of an optical finder, the main imaging sensor provides a full-time live view image via an electronic viewfinder in its place.
All in all, this camera is what I’m looking for. High burst for skateboarding sequence shots, great HD video for any video needs. Now all I’m waiting for is a firmware hack, which shouldn’t be too long!
*lots of review content provided by dpreview.com*