The mirror in the A55 is semi-transparent. According to Sony, it allows 70% of the light that strikes it straight through to the 16.2MP CMOS imaging sensor. The remaining 30% is reflected upwards to a large 15-point phase detection AF array. This equates to a roughly 1/2 EV reduction in light transmission for live view/image capture but means the AF sensor is always receiving light.
原文網址在這裡：http://www.dpreview.com/reviews/sonyslta55/page2.asp
所以，結論是，這種結構必須起碼犧牲 1/3 STOP的快門速度～～
當然，最後的成片應該是沒啥問題的吧，就是快門慢了
XXXSB wrote:
這樣吧，我引用一下Dpreview對A55的review
其實我對dPreview用Class 4的SD然後說打完Buffer要50秒...的測試態度...
個人感到其實也不是這麼公正客觀.
內文搜尋
從 APP 打開
X