Lenstip (Click here) wrote a very detailed and so far best article I have ever read about the Sony SLT tech. The title of the post is: “Everything you always wanted to know about the semi-transparent mirror technology (but were afraid to ask)“.
You absolutely have to read it because it’s really showing on a scientific way how the Sony SLT system works. At the end those are their conclusions based on they tests they made:
A fixed film mirror has a lot of advantages over the classic solution:
- Burst mode can be faster
- Dirt won’t invade the interior of the camera so easily
- The camera might be more reliable
- The camera is physically lighter and can be potentially cheaper
- The camera might offer continuous preview (not necessarily if you deal with an electronic viewfinder, though)
- Phase-detection AF in the LV mode and during registering a movie
Of course there also many reasons why classic reflex cameras have been sold on the market up to now. Some of them are listed below:
- Bright optical viewfinder
- 1/3 more of light = faster speeds or lower ISO, an advantage in dynamic range and noise
- The mirror can be cleaned without any risk and it’s less prone to damage
- A damage of a film mirror influences the resolution of photos; a damage of an ordinary mirror won’t have such consequences.
What I write now is just my private opinion and not based on rumors: I think the SLT tech will not live long. The chance is high on sensor PDAF will become mainstream in the coming years and therefore semitransparent mirror (and even classic DSLR mirror) may become obsolete. Of course this doesnt mean A-mount has to go. It means A-mount becomes mirrorless just like E-mount and as Sony stated recently, they can use the “free space” to explore other new tech (Z-shift and so on).