What focusing points are used with a Sony A6300 camera + LA-EA4 lens adapter?

Question

I'm about to acquire a Sony A6300 e-mount camera.
I wish to use various A-mount lenses with it. Sony sell their LA-EA3 and LA-EA4 adapters to interface A-mount lenses with e-mount cameras.

The LA-EA3 adapter has no inbuilt focusing system and no screw-drive AF system. It allows lenses with inbuilt focus-motors to focus using the cameras focus detection system.

The LA-EA4 adapter has an inbuilt phase focusing system and supports screw-drive AF lenses.

• For A-mount lenses with inbuilt focus motors, use of the EA3 allows the full phase focus capabilities of the A6300.

• For A-mount lenses with mechanical focus drive, use of the EA4 adapter allows motor driven lens focusing, and all A-mount lenses can use phase focusing.

However, with the LA-EA4 the A6300 is attached to an adaptor WHICH CONTAINS an extremely limited number of phase focusing points and the camera is 'looking through' a half stop ND filter.Ideally the A6300 would use its multitude of on-sensor phase focusing points, ignore the EA4's focusing points, and use the EA4 mainly to provide motor-focus-drive to the lens. However various on-web opinions state that in such cases the system uses the few in-adapter phase focus points and ignores the vat number of on-sensor points. This makes very little sense, but may be true.

QUESTIONS:

1. When an LA-EA4 adaptor is used with a A-mount lens does an A6300 use the native sensor-based focusing points or are the limited number of adapter points used?

2. If the EA4 translucent mirror was (properly) removed would the EA4 + A6300 combination function correctly?

Answer 1

However, with the LA-EA4 the A6300 is attached to an adaptor WHICH CONTAINS an extremely limited number of phase focusing points and the camera is 'looking through' a half stop ND filter.Ideally the A6300 would use its multitude of on-sensor phase focusing points, ignore the EA4's focusing points, and use the EA4 mainly to provide motor-focus-drive to the lens. However various on-web opinions state that in such cases the system uses the few in-adapter phase focus points and ignores the vat number of on-sensor points. This makes very little sense, but may be true.

It's wise to keep in context when the LA-EA4 and it's sisters were created in 2013, for the FF ones, and 2010-2011 for the APS-C ones. The Sony aXXXX line that we know it didn't exist for APS-C and the FF release was probably for the A7 and A7R, slow pokes compared to the A7RII and A6300 we have today. For the older A7, the phase detect AF area was rather small and I wouldn't be surprised if that area was the LA-EA4 AF area. The A7R did not have PDAF, from what I remember.

If your goal was to adapt lens, consider the Metabones Canon EF to Sony FE adapter.

1. When an LA-EA4 adaptor is used with a A-mount lens does an A6300 use the native sensor-based focusing points or are the limited number of adapter points used?

1. The LA-EA4 provides 15 auto focus points see this article. You can see what type of autofocus points they are. The image below is the viewfinder of the Sony A6000 which is the same size as the A6300.

2. If the EA4 translucent mirror was (properly) removed would the EA4 + A6300 combination function correctly?

2. I don't know precisely how the AF system is setup. Assuming it is like a DSLR, which it seems like the DSLTs are, then the AF sensors are below the mirror within the adapter. If you remove the mirror then the camera will not be able to AF, as the AF sensors on the bottom on the adapter will not get any light and not know which way to focus. I've not done this done so your mileage will vary.

If you don't want the mirror, then get the LA-EA3? There is also the LA-EA2, LA-EA4 for Sony APS-C and LA-EA1, LA-EA3 for APS-C as well. Assuming you don't plan to upgrade to FF, that might be a cheaper option.

I do own the Sony A6300 but I don't plan on getting the adapters or going down this route.

Answer 2

1. The LA-EA4 uses the adapters AF sensors only and not the cameras, however LA-EA3 uses the cameras AF point and are therefore recommended for the A6300 (but not for the A6000), but doesn't have AF motor for lenses needing screw-drive.

2. No, it would not work at all (no auto focus of any kind at all), but LA-EA3 have no translucent mirror and no light lose, it does and is designed to do what you want, but as you said, requires lenses with build in focus motor.