NEX 6 and pdaf samples

Started Nov 11, 2012 | Discussions
Jason E.
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NEX 6 and pdaf samples
Nov 11, 2012

I recieved my Nex-6 w/ 16-50 kit lens yesterday, so I put it through some initial paces. One recurring theme that keeps coming up on dpreview forums is how well the Nex-6 PDAF perform with movement perpendicular to the sensor (i.e., focus ability with quickly changing distance information).

First a few caveats:

1. This is a rudimentary test, not presented as a definitive professional exercise.

2. The NEX-6 was set to continous AF mode, PDAF enabled, center focus spot only, speed priority drive mode -- all while using the 16-50mm PZ kit lens.

3. The shots were indoor in my basement, with very poor lighting. Consequently, I had to bump up the ISO substantially (noise). Samples are JPEG, straight OOC, sharpness/contrast/saturation all set to "0." I've attempted to upload the native JPEGs from my computer, but I don't know if dpreview will degrade or down-res these images.

4. I kept the aperture larger than 5.6 (f number smaller than 5.6), to make sure that PDAF was enabled.

5. Given the lighting conditions, the shutter speed was suboptimal to freeze all motion optimally.

6. The test subjects, my boys aged 5 and 8, are pretty darn fast. I had them sprint as fast as they could towards the camera. I feel this is an accurate representation of the fastest speed you would likely need to capture most child related activities.

7. I pre-focused on the face, but did not actuate the shutter until after they started running -- to capture photos once movement had already begun. Because they are typical boys, they also skipped/jumped while running -- so the it was really hard to keep the focus point just on the face (probably on the chest a couple times).

8. I didn't spend all day setting up this test, I spent 2 minutes & these were the 1st samples I shot. With practice & improved conditions (and a more optimal lens), I'm sure things would improve.

9. I am migrating from the Canon EOS 40D, and my results are at least as good for straight-line movement as anything I ever accomplished with the Canon. Color me impressed, especially given the sub-optimal conditions for this test.

10. I realize that this test is very amateur-level, so please do not feel compelled to point out the many flaws of my technique or photographic skill. I realize that the high ISO causes noise, the shutter speed is too low to prevent some motion blur, and the focal lengths are sub-optimal. I offer this post simply because I do not see anything similar posted, and think other people on the fence may be interested.

Enjoy! -- other NEX-6 test photos posted here (mainly legacy Canon FDn glass):

https://picasaweb.google.com/100478217890567871686/RememberNovember



1st set: f/5, 30mm, ISO 6400, 1/4000



2nd Set: f/4, 18mm, ISO 1600, 1/400



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cheers,
JSE

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Ronbeau
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 11, 2012

Excellent.  Thanks for doing this.  I've got a nex 6 on the way and have been looking for this kind of test.  I've been planning to do something similar and compare it to my vintage nex 5.

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 11, 2012

Sorry for the typos -- it seems dpreview won't let me edit . . .

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cheers,
JSE

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to Ronbeau, Nov 11, 2012

I'm pleasantly surprised and happy with the results.  Additionally, the low ISO images I'm getting with legacy glass have reassured me that I made the right decision to invest in the Nex system.

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JSE

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Clem Nichols
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 11, 2012

Very helpful, and thanks for your work.  If you could it would be interesting to repeat your experiment at 50mm or an even longer focal length if possible.  Many thanks.

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CN

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to Clem Nichols, Nov 11, 2012

I totally agree that a longer focal length would be best. Unfortunately, the only native e-mount lens I have is the kit PZ -- so I guess I could try the 50mm end.  It's raining here today, perhaps tomorrow -- since I am limited to f/5.6 at 50mm and I would want faster shutter speeds and a low ISO if possible.

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JSE

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Bstevs
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 11, 2012

Thanks for the experiment. Looking forward to others you do as I am also interested in freezing movement.

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Keith Schmidt
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 12, 2012

cute kids.  I don't think your test shows anything about the continuous auto focus though.  At such a wide focal length, pretty much everything in the scene is in focus.

Will be interesting to see how the test looks when you have some good light and can us e the 50mm end.

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malch
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 12, 2012

You couldn't be bothered to build a professionally equipped optical lab for lens testing? I thought that's what basements were for.

Just kiddin'

I think it's a very fine test and the results were, as you say, impressive for a small mirrorless camera. Thanks for posting.

Can't wait for my NEX-6 to arrive in a few more days.

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to Keith Schmidt, Nov 12, 2012

Keith Schmidt wrote:

cute kids. I don't think your test shows anything about the continuous auto focus though. At such a wide focal length, pretty much everything in the scene is in focus.

Will be interesting to see how the test looks when you have some good light and can us e the 50mm end.

Very legitimate point, I really wish I had a telephoto AF lens.  I'll try to test this outside tomorrow at 50mm.

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JSE

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to malch, Nov 12, 2012

I tried to point out some methodological flaws myself, because I was worried I'd embarrass myself on the forum

There is just so much photographic talent that posts on dpreview!

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JSE

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jpr2
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Jason: many thanks - I'd be looking forward....
In reply to Jason E., Nov 12, 2012

Jason E. wrote:

Keith Schmidt wrote:

cute kids. I don't think your test shows anything about the continuous auto focus though. At such a wide focal length, pretty much everything in the scene is in focus.

Very legitimate point, I really wish I had a telephoto AF lens. I'll try to test this outside tomorrow at 50mm.

...to more tests of this kind - as your running/jumping kids are exactly right target - at 50mm and not too large shooting distance, and in a light good enough to fire at higher SS - unfortunately, wide open at 50mm with this PZ means f/5.6, so little chance to see a truly narrow DOF results of fast action N6 shooting

any chance for you to rent/borrow 22-210?

best, jpr2

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andres76
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 12, 2012

Nice test.

Thank you.

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Sergey Borachev
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 12, 2012

Thanks, Jason.

Does it have to be faster than f/5.6 for PDAF to work?  How about f/5.6?

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S.A.
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Re: NEX 6 and pdaf samples
In reply to Jason E., Nov 12, 2012

Thank you for the test. It looks as if AF tracking of moving subjects is now at least doable. Too bad the available zooms are too slow to take advantage of it without being completely wide open. Where is the G standard zoom Sony?

All these years of digital cameras and we are still wanting for dependable AF... Come on!

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Scott A.
A few pics

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Jason E.
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Re: NEX 6 and pdaf samples
In reply to Sergey Borachev, Nov 12, 2012

Sergey Borachev wrote:

Thanks, Jason.

Does it have to be faster than f/5.6 for PDAF to work? How about f/5.6?

From my nex-6 manual: "When the aperture value is greater than F6.3, Phase Detection AF is unavailable. You can only use Contrast AF.  Phase Detection AF is available only with compatible lenses. If an incompatible lens is attached, you will be unable to use Phase Detection AF."

I take this to mean the following:

1.  Aperture needs to be equal or larger diameter to F6.3 (i.e., f stop # 6.3 or smaller number).

2.  Use of a compatible lens (w/ updated firmware).

If the above criteria are satisfied, PDAF should be active.

my $0.02,

JSE

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Jason E.
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Re: Jason: many thanks - I'd be looking forward....
In reply to jpr2, Nov 12, 2012

jpr2 wrote:

...to more tests of this kind - as your running/jumping kids are exactly right target - at 50mm and not too large shooting distance, and in a light good enough to fire at higher SS - unfortunately, wide open at 50mm with this PZ means f/5.6, so little chance to see a truly narrow DOF results of fast action N6 shooting

any chance for you to rent/borrow 22-210?

best, jpr2

I'm tempted to rent one, but can't justify pulling the trigger unless I have a dual purpose/event :-).

Actually, I think a fast prime (i.e., 50mm f/1.8) would approximate the DOF test for fast action testing -- I'm considering picking this one up.  The problem -- it's that loud silver & apparently the AF drive motors for this lens are not the fastest from what I've read on these forums.

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cheers,
JSE

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jpr2
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re: currently the 50/1.8 is not on the list of PDAF compatible lenses...
In reply to Jason E., Nov 12, 2012

Jason E. wrote:

jpr2 wrote:

...to more tests of this kind - as your running/jumping kids are exactly right target - at 50mm and not too large shooting distance, and in a light good enough to fire at higher SS - unfortunately, wide open at 50mm with this PZ means f/5.6, so little chance to see a truly narrow DOF results of fast action N6 shooting

any chance for you to rent/borrow 22-210?

best, jpr2

I'm tempted to rent one, but can't justify pulling the trigger unless I have a dual purpose/event :-).

Actually, I think a fast prime (i.e., 50mm f/1.8) would approximate the DOF test for fast action testing -- I'm considering picking this one up. The problem -- it's that loud silver & apparently the AF drive motors for this lens are not the fastest from what I've read on these forums.

...so will not answer any questions abt. fast action shooting and tracking and it well might be that such compatibility is not in S's plans at all !!

jpr2

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jpr2
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re: currently the 50/1.8 is NOT on the list of PDAF compatible lenses...
In reply to Jason E., Nov 12, 2012

Jason E. wrote:

jpr2 wrote:

...to more tests of this kind - as your running/jumping kids are exactly right target - at 50mm and not too large shooting distance, and in a light good enough to fire at higher SS - unfortunately, wide open at 50mm with this PZ means f/5.6, so little chance to see a truly narrow DOF results of fast action N6 shooting

any chance for you to rent/borrow 22-210?

best, jpr2

I'm tempted to rent one, but can't justify pulling the trigger unless I have a dual purpose/event :-).

Actually, I think a fast prime (i.e., 50mm f/1.8) would approximate the DOF test for fast action testing -- I'm considering picking this one up. The problem -- it's that loud silver & apparently the AF drive motors for this lens are not the fastest from what I've read on these forums.

...so will not answer any questions abt. fast action shooting and tracking and it well might be that such compatibility is not in S's plans at all !!

jpr2

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quezra
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Re: Jason: many thanks - I'd be looking forward....
In reply to Jason E., Nov 12, 2012

Jason E. wrote:

jpr2 wrote:

...to more tests of this kind - as your running/jumping kids are exactly right target - at 50mm and not too large shooting distance, and in a light good enough to fire at higher SS - unfortunately, wide open at 50mm with this PZ means f/5.6, so little chance to see a truly narrow DOF results of fast action N6 shooting

any chance for you to rent/borrow 22-210?

best, jpr2

I'm tempted to rent one, but can't justify pulling the trigger unless I have a dual purpose/event :-).

Actually, I think a fast prime (i.e., 50mm f/1.8) would approximate the DOF test for fast action testing -- I'm considering picking this one up. The problem -- it's that loud silver & apparently the AF drive motors for this lens are not the fastest from what I've read on these forums.

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cheers,
JSE

50/1.8 isn't PDAF compatible yet so hold on.

Nice shots though, cute boys!

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