Sony alpha a-mount af lenses on a NEX?

[cooltouch]

Do I have to use that Sony adapter for a-mount lenses on my NEX, or can I get by without one? What will happen if I don't use the adapter?

Edit: I googled this topic and found answers. Looks like I'll need either the LA-EA3 or LA-EA4. I'm not really sure about the differences and which would work best on my NEX 7 though. Also I'm wondering if there are any third party adapters that are worth considering. Your comments are welcome.

[calvin83]

LA-EA3 or LA-EA4 is made for FF or APS-C.
LA-EA1 or LA-EA2 is made for APS-C only.

LA-EA2 and LA-EA4 has build in motor and a mirror with phase detection unit. They are designed for A-mount lens without build in motor.
LA-EA1 and LA-EA3 are initially design for video camera who need no auto-focus. They have no build in motor.

For lens with build in motor(SAM or SSM), you can use any of the adapter above. However, the focus will be very slow on LA-EA1 and LA-EA3 unless it is used on the new A7R2 which support on sensor phase detection focus.
For the old A-mount lens with an aperture lever, you can use a non-electrical OEM adapter with aperture control with loss of AF.

[Teo]

I would be interessed too in this problem , mainly for the 35/1,8 Alpha on the nex ...But if it focuses painly slow ,and the price of the lens with an adapter is almost like the 35/1,8 oss ....mmm

[Tedat]

the Sony DT 35mm F/1.8 SAM has a build in motor which means AF works with all LA-EA adatapter. However.. with LA-EA1 and LA-EA3 it will use only contrast detection on every E-Mount camera except the new A7R-II and this is slow.

With LA-EA2 and LA-EA4 it will use phase detection and is fast as on a A-Mount body