topic Re: A99 AF System in Alpha & NEX interchangeable lens cameras

A99 AF System

mikeyp2000 — Thu, 13 Sep 2012 20:31:47 GMT

Hi,

The new A99 looks very interesting but I think there is considerable confusion about the new AF system.

If I understand correctly, there are now two AF systems - the normal PDAF points using the SLT mirror and phase detect pixels on the actual image sensor (let's call those PDOS points for Phase Detect On Sensor).

Here are some questions...

1) There is a new AF mode called "AF-D". Can someone inside Sony explain the benefits and operation of AF-D?

2) Is this correct - "AF-D only works with a limited list of supported lenses."?

3) What is the roadmap for supporting extra lenses? Any plans for supporting 3rd party lenses? (Sigma, Tamron etc)

4) Without lens support, I suppose AF-D will not work. Will the normal AF-A, AF-S and AF-C then totally ignore the PDOS AF points, relying on the usual standard PDAF points?

5) The new AF Range feature looks extremely interesting. Will this only work with AF-D supported lenses? Or is it available to all lenses with distance coding (so called "D" lenses that also support with ADI flash)?

I'm sure the A99 might generate many more similar questions!

Cheers

Re: A99 AF System

Thalamus. — Thu, 13 Sep 2012 22:20:07 GMT

Hi mikeyp2000,

without official documentation it's hard to give answers on these questions but lets see if I can find someone from Sony who can help..:smileyconfused:

Re: A99 AF System

alphaholic — Sat, 15 Sep 2012 17:53:21 GMT

Hi Mikeyp2000

Here you will find some answers;

http://www.youtube.com/watch?v=tvFgUrHgsiI&feature=relmfu

And these lenses ale allready AF-D compatible: SAL-2470Z, SAL-2875, SAL-50F14, SAL-300F28G2, SAL-70400G and SAL-500F4G. More also older Lenses will be updatet (Also Tamron and Sigma lenses)

Cheers

alphaholic

Re: A99 AF System

Thalamus. — Tue, 18 Sep 2012 15:26:56 GMT

Got some answers for you..

mikeyp2000 wrote:

1) There is a new AF mode called "AF-D". Can someone inside Sony explain the benefits and operation of AF-D?

AF-D stance for AF Depth map assisted. Benefit is that both AF sensor (19 points) and AF detection zone on main imager (102 points are working together so that proper focus can be maintain even if the subject goes out of the AF sensor 19 points frame. Perfect for tracking moving subject.

mikeyp2000 wrote:

2) Is this correct - "AF-D only works with a limited list of supported lenses."?

Think this has already been answered above..

mikeyp2000 wrote:

3) What is the roadmap for supporting extra lenses? Any plans for supporting 3rd party lenses? (Sigma, Tamron etc)

More Sony lenses will hopefully be supported by future firmware release

mikeyp2000 wrote:

4) Without lens support, I suppose AF-D will not work. Will the normal AF-A, AF-S and AF-C then totally ignore the PDOS AF points, relying on the usual standard PDAF points?

With non-supported lenses, no AF-D cannot be used. Only the 19 points AF sensor will be used.

mikeyp2000 wrote:

AF Range Control will work with all lenses.

Re: A99 AF System

mikeyp2000 — Mon, 24 Sep 2012 14:02:35 GMT

Thanks for the info everyone.

The only bit I'm misunderstanding still is the potential support for AF-D with 3rd party or Minolta lenses. (yes, I have a fair few of these!). I couldn't see the bit in that YouTube vid where anyone mentions 3rd Party lenses being on the roadmap for AF-D support.

Also, is it possible to find out if any DT lenses will be supported? The a99 with 16-50/2.8 DT mounted might be interesting; as an aps-C lens, I believe the a99 fills the evf with a cropped aps-c view do it would seem an a77 evf with 102 extra AF points, approx 10mpix aps-c crop and 6fps. That could be quite cool!

Also, is it possible to force an aps-c crop view, even on a full frame lens? What happens to the raw files in that case? Would they be just the 10mpix aps-c crop or the full 24mpix, vignette and all?

You can probably guess where I'm going with this - perhaps the a99 could replace my a77. They are similar in size and the a99 might possibly give good support for my DT lenses while allowing the full glory of full frame when it suits me...

Re: A99 AF System

alphaholic — Thu, 04 Oct 2012 10:45:36 GMT

Some news:

"But as I told you before firmware updates will be released to support more lenses. Sony Japan said that by early 2013 also these lenses will be supported: 24-70mm f/2.8, 28-75mm f/2.8, 50mm f/1.4, 300mm f/2.8, 70-400mm f/4-5.6, 500mm f/4, 85mm f/1.4, 135mm f/1.8, 70-300mm f/4.5-5.6, 70-200mm f/2.8, 100mm f/2.8, 300mm f/2.8."

Sorry, no newas about the Sigma-, Tamron- and Minoltalenses...

cheers

alphaholic

Re: A99 AF System

cmosse — Wed, 17 Oct 2012 10:42:51 GMT

It is possible to use full frame lenses in APS-C capture mode. The SLT-A99 will capture a 10Mpix image (the viewfinder will show the full 100% field of view though)

The RAW file of an image taken in APS-C mode will have reduced size according to the 10 Mpix resolution.

Re: A99 AF System

Dennis_photo — Sun, 21 Oct 2012 16:32:41 GMT

It would be very interesting to read just why on-sensor PDAF need firmware support for each lens it is supposed to work for. "Normal" PDAF works with all AF lenses. So why exectly is PDAF on the sensor different?

Is there a technical description available somewhere online?

If so, a link to that document would be very appreciated by this curious engineer.