how can the NEX auto-focus miss these shots?

Started 7 months ago | Discussions
joe6pack
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My NEX-3N refuses to take an out of focus picture
In reply to Sir Punk, 7 months ago

Occasionally, I share similar frustration with OP. This usually happen when I try to catch a moment and moved my camera very quickly. For some reason, my 3N (I don't think this is specific to 3N) will refuse to take picture unless it found something to focus. And if I release my finger off the shutter before a picture is taken, the camera simply pretend that I never press it.

This is very different from my XZ-1, which it will try to focus and take a picture regardless.

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Manny316
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 7 months ago

Sir Punk wrote:

I know the photographer makes a difference but I am getting annoyed with my nex 5R because sometimes it misses good shots where autofocus and the subject in question shouldn't be trivial to figure out it should be in focus. I don't always or want to change the focus point because sometimes there is just no time and it should be evident. Look here... what do you guys think? I had face detection on (regist faces) but I have no faces registered, regardless, why is it focusing on everything else but the subject in the center. I have multi-area focus mode. Is there a setting I am missing somewhere?

this looks to be in better focus until you look at it closer or in full screen

I feel your pain. I tried using the Sel 50mm 1.8 for indoor basketball once. I used center focus point and even for stationary moments the Auto-focus was atrocious. Let's just say I went back to using manual focus lenses for sports.

Center auto-focus on the players chest

Missed a great shot due to horrible auto-focus. Hopefully the Sony A6000 is much better and faster.

. Camera focused on the coach instead.

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YLK
YLK
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Re: how can the NEX auto-focus miss these shots?
In reply to Manny316, 7 months ago

After initial frustration with focusing on my NEX 5t (compared to DSLR, though DSLRs are also not to be trusted completely when it comes to focusing, though they are definitively faster) and help from forum members here are my advices:
1.Accept the fact that your camera is not too fast or correct with focusing.
2.Choose Flexible Spot (gives the smallest focusing area)
3.Use DMF to know where more-less the camera focuses on; remember, it's also contrast based, so it will show the color lines along areas with strong contrast, but they may not necessarily be in focus (at least this is my experience)

I still think it is very much about realizing NEX is not very fast or accurate at focusing, once you accept it you will be fine...:) In fact I'm learning manual focusing now, new and usefull skill; while for run and gun photography use P&S.

Goog luck!

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jpr2
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re: the fact that my N7's AF'ing is a total rubbish...
In reply to YLK, 7 months ago

YLK wrote:

I still think it is very much about realizing NEX is not very fast or accurate at focusing, once you accept it you will be fine...:) In fact I'm learning manual focusing now, new and usefull skill; while for run and gun photography use P&S.

  • ...was immediately obvious since the very I-st day after purchase;
  • the skill of MF'ing was already acquired about three decades earlier - still in a depth of that so very remote film era ;
  • alas... MF'ing is sufficient for about 70% of my photo ops (at best, but we tend to be very lenient and forgiving in this thread);
  • unfortunately, P&S won't do... as my predilection is to shoot wide open for a paper thin DOF;

however, this thread very brilliantly illustrates what exactly is wrong with AF of the Nex'en, and why the a6k might such a breakthrough = that is IFF confirmed

jpr2

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sean lancaster
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Re: re: the fact that my N7's AF'ing is a total rubbish...
In reply to jpr2, 7 months ago

jpr2 wrote:

this thread very brilliantly illustrates what exactly is wrong with AF of the Nex'en, and why the a6k might such a breakthrough = that is IFF confirmed

a big IF, eh?

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OpticsEngineer
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 7 months ago

In autofocus modes, I have figured out that my NEX7 focuses on the areas that are the brightest.

People always say the AF picks the areas with the most contrast.  But in my experience, that just is not correct.

In the picture with the blurry face, if you look in the left hand side you see a brighter area of foliage that is in focus.  Just as an example.

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telefunk
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Re: how can the NEX auto-focus miss these shots?
In reply to OpticsEngineer, 7 months ago

Mmmm interesting observation. I will check it out.

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GaryW
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Re: how can the NEX auto-focus miss these shots?
In reply to Manny316, 7 months ago

Manny316 wrote:

Camera focused on the coach instead.

I don't see this in the 2nd shot, but in the first one it looks to me like the audience and the coach are in focus. This seems like an example of a low-contrast target where the camera picks up on a higher-contrast background.

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Bolshevik
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Re: how can the NEX auto-focus miss these shots?
In reply to GaryW, 7 months ago

There is one more weird thing with NEX`s AF - it don`t like moving targets at all.

If you try to focus at something moving - it`s a great probability that you will have good focused background. Especially if it is bright/contrast enough.

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captura
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Re: how can the NEX auto-focus miss these shots?
In reply to andrewD2, 7 months ago

andrewD2 wrote:

I don't trust face detect, the edge of the face with the background often has a higher contrast than the features of the face. Sharp ears and blurry eyes are no good to me.

Fire a few shots off with the spot focus on the face (eye if you are close enough) and you'll have a choice of sharp shots AND expressions. Also if you use "DMF" you'll have the zoom in fine focus on the right area.

Try 2 shots with flexible spot to get the shot well enough and avoid subject from getting bored then fine tune the 3rd if she is still there!

Andrew

Olympus gives you not only "eye" detection, but the choice of which eye, l. or r. !

Stev

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captura
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Re: how can the NEX auto-focus miss these shots?
In reply to semifast, 7 months ago

semifast wrote:

I know this won't be popular but this issue is one of the reasons I like to use my Nikon J2 more than the 5r or Alpha A37 I used to have. The J2 seems to know what to focus on and does it very quickly.

I'm hopeful the A6000 will match the Nikon 1 Series in this regard as it will then be near perfect for me. Except it will probably be so popular I'll never get a deal on it.

I have the same experience with the J1 compared to my 5R. Focusing and more importantly, tracking is better with the Nikon 1. Hopefully the A6000 will be as good.

Steve

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captura
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Re: how can the NEX auto-focus miss these shots?
In reply to Manny316, 7 months ago

Manny316 wrote:

Sir Punk wrote:

I know the photographer makes a difference but I am getting annoyed with my nex 5R because sometimes it misses good shots where autofocus and the subject in question shouldn't be trivial to figure out it should be in focus. I don't always or want to change the focus point because sometimes there is just no time and it should be evident. Look here... what do you guys think? I had face detection on (regist faces) but I have no faces registered, regardless, why is it focusing on everything else but the subject in the center. I have multi-area focus mode. Is there a setting I am missing somewhere?

this looks to be in better focus until you look at it closer or in full screen

I feel your pain. I tried using the Sel 50mm 1.8 for indoor basketball once. I used center focus point and even for stationary moments the Auto-focus was atrocious. Let's just say I went back to using manual focus lenses for sports.

Center auto-focus on the players chest

. Camera focused on the coach instead.

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You could try it again, this time using Sports Action mode.

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boogieboogie
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Re: how can the NEX auto-focus miss these shots?
In reply to eths, 7 months ago

This is pretty typical of my NEX C3 and why I'm looking elsewhere for a replacement. It's not that it's slow lit's just oh so wrong most of the time. You're left thinking - what the hell is it focussing on? Even if it's on spot focusing it seems to focus on somewhere else entirely. The newer models are supposed to be an improvement but together with the build quality I've lost confidence in sony kit.

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mbietenholz
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Re: how can the NEX auto-focus miss these shots?
In reply to OpticsEngineer, 7 months ago

OpticsEngineer wrote:

In autofocus modes, I have figured out that my NEX7 focuses on the areas that are the brightest.

People always say the AF picks the areas with the most contrast. But in my experience, that just is not correct.

In the picture with the blurry face, if you look in the left hand side you see a brighter area of foliage that is in focus. Just as an example.

I don't think that is what is happening here - the face itself is probably at least as bright as that area of foliage.  In this picture, the camera clearly focussed on the background, and I suspect it is because the background (including that area of bright foliage) is higher contrast, and because there is more of it, than the face.

You can only measure contrast over some area in the image - ie. you need many pixels, there's no contrast in a single pixel .  The most obvious choice would be just to maximize the contrast over the whole picture, which would probably get you a
 a result close to the blurry-face picture, background in focus because there is much more of it and it is higher contrast.

The NEX cameras likely do something a little more sophisticated than just maximizing the contrast over the whole image, and try to divide the image into different areas, and then decide which one to maximize the contrast on.

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bigley Ling
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Re: how can the NEX auto-focus miss these shots?
In reply to mbietenholz, 7 months ago

any chance facial recognition has not been enabled?

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FuzzyQball
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 7 months ago

The AF system is not terribly reliable.  In the first one it clearly focused on the background.  The other two look like the camera never achieved focus.  Do you half push the shutter and wait that fraction of a second to make sure that focus is achieved.

Face detection would definitely help these turn out better.  I just leave it on.  I also turn on focus peaking and check for focus location before I fire the shutter.

Not sure what your previous camera was, but many P&S cameras tend to use small apertures, making focus errors less noticable.  The NEX series tries to isolate the subject, and focus areas are obvious.

The focus system is not the best, but I manage OK with it.

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Sir Punk
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Re: how can the NEX auto-focus miss these shots?
In reply to FuzzyQball, 7 months ago

Yes I always press the trigger half-way and wait for focus confirmation. I have been doing it for 10 years now.

I have had the 5r for over a year now, I guess I haven't learned its quirks yet. I had a panasonic lx3 before and never missed one portrait shot.

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Caris
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Re: re: the fact that my N7's AF'ing is a total rubbish...
In reply to jpr2, 7 months ago

jpr2 wrote:

however, this thread very brilliantly illustrates what exactly is wrong with AF of the Nex'en, and why the a6k might such a breakthrough = that is IFF confirmed

jpr2

I doubt it very much. The AF in a6000 may be better in AF-C for focus tracking but in AF-S,  the AF accuracy all be as dismal as in the previous NEX models.

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Caris
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 7 months ago

Sir Punk wrote:

Yes I always press the trigger half-way and wait for focus confirmation. I have been doing it for 10 years now.

I have had the 5r for over a year now, I guess I haven't learned its quirks yet. I had a panasonic lx3 before and never missed one portrait shot.

Contrary to most previous suggestions ( face detect on or centre spot and re-compose ),  I found the flexible spot focus point the most reliable in situations like yours.

You have a touch screen on your 5R - use it to select the face and in 95% of the times it will be in focus. If you are close enough, touch the eyes or if you are further away like in your 1st shot, just select the whole face with the flexible spot point and it won't focus on the background. I use this method when I have people/faces as subjects, otherwise centre spot for architectural/city shots and sometimes multi-point for landscapes. When I want to focus on a small detail  ( especially off- centre ) I always use the flexible spot ( and if I have time to double check the accuracy, I use DMF for confirmation ).

Obviously, you could simply use MF, in fact sometimes it's quicker than to double-check the AF accuracy via DMF on NEX!

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Absence Of Faith
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Re: how can the NEX auto-focus miss these shots?
In reply to Caris, 7 months ago

I also find that Flexible Spot works for me as well. In fact, contrary to many here, I find both my 5n and Nex 6 to be the most accurate cameras I've owned, focus-wise. They're infinitely more accurate than the Nikon D5000 I've owned in the past.

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