With the world’s fastest autofocus system (A6000)

Started Feb 12, 2014 | Discussions thread
GaryW Veteran Member • Posts: 8,616
Re: re: not necessarily

jpr2 wrote:

erringtont wrote:...

For example, if I'm shooting the NEX 6 in Aperture Priority mode with the 16-50 kit lens and have selected f8 for the aperture the camera is using only Contrast Detect to acquire focus.

But what happens in P-mode at f8? It uses a wider aperture when focusing. Since it has a wider aperture, PDAF should be possible. Whether or not PDAF is used is hard to tell. Perhaps changing the aperture helps CDAF focus as well? If so, then that would explain why we still see the behavior with CDAF lenses. If focusing with a wider aperture doesn't help anything, why does the camera do it?

Since the A7 specification pushes this limitation up it represents an improvement over the NEX 6, perhaps the a6k will exhibit similar improvement.

  • ....why? because all AF'ing will be done at the lens set wide open!! and iris will be closed only upon actual exposure taking place (just a bit earlier than the shutter release);
  • with Nex'en it is a bit different - and I'm not familiar with every Nex camera sufficiently to give you exact details: with some it is possible to operate them in the same way as described for the 7d;

It looks to me like it opens the aperture in P and S modes, and stops them down with the half-press.

  • I certainly can shoot my Nex7 this way with EF lenses mounted through the Conurus/MB smart adapter (SA), or speed boosetr (SB);
  • but the Sony's default is to close the iris as soon as the value is set - supposedly to render the actual DOF in VF, but for me this seems like not good enough a reason to rob the users' of all the AF'ing benefits of the other approach;

In A-mode, it's set immediately.  You asked for a specific aperture for a reason, so it makes sense that it gives it to you.   In the other 2 modes, closing the iris immediately doesn't seem to be the default.  I didn't look at other modes or iAuto.


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Gary W.

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