This is an in-depth review of the Sony SLT-A77 digital SLR camera that was announced together with the Sony SLT-A65 in August of 2011. I had a chance to test both cameras, along with a number of Sony / Zeiss lenses for the Sony mount, while reviewing the Nikon 1 camera system in late 2011. While I concentrate most of my gear reviews around Nikon cameras and lenses, I got really excited about these Sony cameras after seeing the press release and decided to try them out.
Yesterday Sony released two brand new cropped-sensor DSLRs – the Sony Alpha A77 and Sony Alpha A65. Actually, it is not right to call these cameras DSLRs, because they are not equipped with a traditional DSLR mirror. Instead, the A77 and A65 use a “translucent mirror“, so the correct terminology is “Single-Lens Translucent” (versus Single-Lens Reflex), or “SLT”. On traditional DSLRs, the camera mirror reflects the light coming from the lens into both the viewfinder and the AF sensor, allowing the camera to quickly acquire focus through the phase-detection system. When a picture is taken, the mirror gets raised, thus blocking the viewfinder and preventing the light from reaching the AF sensor. Because of this, the camera can only focus using contrast-detect, which is much slower than phase-detect. Sony’s translucent mirror, on the other hand, allows the light to pass through the mirror and hit the camera sensor, simultaneously reflecting some of the light off the mirror on to the AF sensor. The mirror never moves and stays in the same spot. This allows the camera to acquire focus with the phase detection system even when shooting video. Because the shutter is the only moving component inside the camera, images can be captured at crazy fast speeds. For example, the top-of-the-line Nikon D3s can loudly capture 9 frames per second maximum, while the new Sony Alpha A77 SLT can take 12 frames per second and the only thing you will hear is the sound of shutter opening and closing. There are many advantages to SLTs like smaller size, less camera shake, etc.
NOTE: A full Sony A77 Review has been published.