how can the NEX auto-focus miss these shots?

Started 10 months ago | Discussions
GaryW
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Re: Common Frustration.....Face Detection Help to alleviate the AF inconsistancy
In reply to 007peter, 10 months ago

007peter wrote:

Sadly, an all too common experience for most of us here soon or later.

My NEX C3 (no PDAF) will sometimes missed shot that is right in front of it. Its a source of my constant annoyance with NEX. I found these steps helps:

1. Take multiple shots of the same scene (machine gun approach), then threw away the OOF

2. Sony Face Detection (and Smile Shutter) works surprisingly well

It does, but sometimes the Nex cameras will STILL stubbornly focus on the background, if right around the head is a high-contrast background -- strong lines, a bush with sharp-edged leaves, etc.

They help to alleviate my NEX AF frustration, but I got tired of inconsistent result and sold my NEX. The new Sony A6000 AF seem very promising. Unlike NEX 5R with its exaggerated PDAF claim, the new A6000 seem to have nailed it on the AF. I'm looking forward to A6000 with cautious optimism.

The PDAF adds speed more than accuracy, I think, but I do feel that my Nex-6 is better than my Nex-5, for whatever reason.  Occasionally I need to either half-press again or retake the shot, but it seems better.

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C.Eaton
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 months ago

Are you absolutely sure that you didn't half press the shutter as you were bringing the camera up?

Just a thought as this would certainly account for the first image being focussed on the background.

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

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Dirk W
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Easy solution
In reply to Sir Punk, 10 months ago

1. Use center focus point

and 2. turn on focus peaking

and 3. turn on DMF

then you will always see if the camera's autofocus sits right.

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davect01
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Re: how can the NEX auto-focus miss these shots?
In reply to j0sh, 10 months ago

j0sh 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?

If you want to focus where you want don't let the camera decide...

-- hide signature --

Yup, that's the joy of letting the camera focus for you. I use DMF a lot, just to make sure I am getting what I want in focus. Really annoying though, I know.

As mentioned, try changing up the AF mode.

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http://davesnex-3photos.blogspot.com/

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spacemn
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Re: how can the NEX auto-focus miss these shots?
In reply to jamesbm, 10 months ago

jamesbm wrote:

spacemn wrote:

Use a smaller AF centre box and recompose, or use the awesome eye AF feature if you using native lenses.

I have a NEX-7 and face detection works ok. I use its quite a lot even in M. However AF does not appear to be a NEX strength until perhaps now.

What is the eye AF feature? Is this only in newer models?

Thanks

Yes, I think the A7 and A7R are the first Sony bodies with this feature. Essentially you can press a programmed button and the camera will attain focus on the eyes.

See this video (from 50 secs and onwards):

http://www.youtube.com/watch?v=WFdbBTYbSXM

It actually works in real life. Pretty awesome if you ask me.

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TiagoReil
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 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

Well, the nex line backfocuses sometimes, as people explained, cause of contraste, etc. There are things you can do to avoid it. I will explain what I do, but many peopel have already expalin some of them.

I dont have my nex-6 here with me, so some things that I will say may not be the exact name, but you will understand them.

First, the focus type(multipoint, center, flexible spot) change it to flexible spot. Select the center spot, but change it if needed, specially for portrait orientation (not this case)

Second set the focus mode to DMF.

Third set peaking on, to a color that matches the sceene. You may need to change thsi from time to time if the sceene needs it.

Last set AF ilumination to off.

With these changes you will reduce the possibility of backfocus, but they will still happen. But with this configuration you can check it.

HAlf press to get focus and check the peaking. Check if it is on your subject or the background. If on the background, start moving the point arround the subject till it finds a contrasty zone that will show the peaking. Focus there and recompose. With practice this becomes authomatic. Also with practice you start recognizing the zones that are easier to get focus.

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

All these things come with practice, with understanding how the camera works and not fighting it but using its quirks to your advantage. Hope this helps.

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spacemn
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Re: how can the NEX auto-focus miss these shots?
In reply to TiagoReil, 10 months ago

TiagoReil 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?

...

...

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

...

Not correct what you are saying about vertical lines. Try focus on verticals, focus acquisition is not a problem.

The focussing system functions as a single line type focussing point as opposed to cross type focus point of a DSLR.

The focussing system will not focus on horizontal lines in parallel with the horizontal sensor borders. Vertical lines are just fine. A cross type focus point would focus on both horizontal and vertical.

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andrewD2
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 months ago

I find the 5R focuses very well. I use it quite differently. Never tried face detect.
I move the smallest focus square to the subject and shoot. Bottom button is can be set to move the square around or you can touch the screen. It calls it flexible spot under Menu --> camera --> auto focus area --> flexible spot. Turn off object tracking.

Focus and recompose sucks for so many reasons, here are a few - you have to do it every time and can miss expressions, you are moving the OSS around for no good reason rather than holding the lens camera steady, you can get backfocus due to hand movement or body sway from lock to shooting time.

Andrew

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captura
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Re: how can the NEX auto-focus miss these shots?
In reply to blue_skies, 10 months ago

blue_skies wrote:

Did you press the shutter too quickly all the way through?

The 5R should have used phase-detection at 55mm f/5.6 1/125 ISO 100, and should have resolved the focus, especially in multi-mode with face detection on.

Face registration does not matter - it only tells the camera which face to focus on if there are multiple faces defected within the frame.

Even with the white background, the PDAF should have worked.

The first image looks like a classic CDAF background focus problem.

Is your lens updated for PDAF support?

Did you get too close (mfd limits)?

Did you press too hard and moved the camera?

Did you press too quickly (should work in PDAF mode though)?

Are these one-off, or typical results for you? If one-off, the white background may be culprit.

Do you have another PDAF enabled AF lens and if so, do you get same results? How about with this lens at 35mm position?

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Cheers,
Henry

I believe you said that you use center focus. If you engage hybrid PDAF, you will see the multi-point array on the screen; if you don't you have not enabled PDAF. Which is far, far better to get fast accurate focus for many kinds of images.

Both 'hunting' and focusing on the background will stop in the majority of cases.

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captura
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Re: Common Frustration.....Face Detection Help to alleviate the AF inconsistancy
In reply to 007peter, 10 months ago

+1

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EinsteinsGhost
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Re: how can the NEX auto-focus miss these shots?
In reply to spacemn, 10 months ago

TiagoReil 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?

...

...

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

...

Not correct what you are saying about vertical lines. Try focus on verticals, focus acquisition is not a problem.

The focussing system functions as a single line type focussing point as opposed to cross type focus point of a DSLR.

The focussing system will not focus on horizontal lines in parallel with the horizontal sensor borders. Vertical lines are just fine. A cross type focus point would focus on both horizontal and vertical.

That would be with PDAF (and all PDAF points on hybrid AF are cross type whereas DSLRs usually have only a few cross type). With contrast detect should be all about contrast itself.

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telefunk
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Re: how can the NEX auto-focus miss these shots?
In reply to andrewD2, 10 months ago

Exactly! In the meantime I am trying to make the best composition et al. The camera should be doing its focussing job whilst I concentrate on the (very quick) composition. No?

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TiagoReil
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Re: how can the NEX auto-focus miss these shots?
In reply to spacemn, 10 months ago

spacemn wrote:

TiagoReil 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?

...

...

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

...

Not correct what you are saying about vertical lines. Try focus on verticals, focus acquisition is not a problem.

The focussing system functions as a single line type focussing point as opposed to cross type focus point of a DSLR.

The focussing system will not focus on horizontal lines in parallel with the horizontal sensor borders. Vertical lines are just fine. A cross type focus point would focus on both horizontal and vertical.

I remember having problems with verticals. I could be wrong. but it happens. I will test it when Im back home. But any case. Vertical, horizontal, if any of them is (Im almost sure is vertical, or maybe I was holding the camera in portrait way), just tilting, adquiring focus, and tilting back solves the problem.

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andrewD2
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Re: how can the NEX auto-focus miss these shots?
In reply to telefunk, 10 months ago

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

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semifast
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 months ago

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.

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Sir Punk
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Re: how can the NEX auto-focus miss these shots?
In reply to andrewD2, 10 months ago

thanks to all of you for the precious advice. Apparently you can only use face detection with multi. Right now I have DMF and peaking on. One thing I am confused about DMF. I press half-way then I can turn the lens ring and it will auto-zoom, but when I turn the ring it looses the focus that was set by the camera, is there a way to look at auto-focus without changing the focus determined by the camera?

I have to say that the peaking color is somewhat annoying.

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spacemn
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Re: how can the NEX auto-focus miss these shots?
In reply to TiagoReil, 10 months ago

TiagoReil wrote:

spacemn wrote:

TiagoReil 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?

...

...

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

...

Not correct what you are saying about vertical lines. Try focus on verticals, focus acquisition is not a problem.

The focussing system functions as a single line type focussing point as opposed to cross type focus point of a DSLR.

The focussing system will not focus on horizontal lines in parallel with the horizontal sensor borders. Vertical lines are just fine. A cross type focus point would focus on both horizontal and vertical.

I remember having problems with verticals. I could be wrong. but it happens. I will test it when Im back home. But any case. Vertical, horizontal, if any of them is (Im almost sure is vertical, or maybe I was holding the camera in portrait way), just tilting, adquiring focus, and tilting back solves the problem.

No, there are no problems with verticals, that is 100%. Not on NEX cameras, not on A7(r)... only horizontals are a problem... same as with other mirrorless cameras, such as the OMD EM1 for example.

Try do focus peaking, you will always see peaking on vertical line (top-bottom) but never around horizontal lines. Try also do AF on horizontals, you'll never get focus lock, but on verticals instantly.

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andrewD2
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 months ago

The first turn should zoom in on the autofocus focal distance, only after it's woken up does it change the focus manually. Does take a bit of practice not to activate and move the focus. Try a sharp turn as if you are turning it on then pause before moving it to tweak.

Andrew

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spacemn
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Re: how can the NEX auto-focus miss these shots?
In reply to EinsteinsGhost, 10 months ago

EinsteinsGhost wrote:

TiagoReil 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?

...

...

Another thing you will notice with the focus, when trying to get focus on straight lines, is that you cant have them paralell to the sensor borders. If it is completely horizontal, or completely vertical, tilt the camera, get focus, and tilt it back till it is straight. Many AF systems have probelms with straight lines paralell to the borders. Dont know why. Just tilting it 20' is enough to get focus.

...

Not correct what you are saying about vertical lines. Try focus on verticals, focus acquisition is not a problem.

The focussing system functions as a single line type focussing point as opposed to cross type focus point of a DSLR.

The focussing system will not focus on horizontal lines in parallel with the horizontal sensor borders. Vertical lines are just fine. A cross type focus point would focus on both horizontal and vertical.

That would be with PDAF (and all PDAF points on hybrid AF are cross type whereas DSLRs usually have only a few cross type). With contrast detect should be all about contrast itself.

No, PDAF points are not necessary cross type. You have DSLRs with both cross type AF points and line type (or whatever the simple PDAF focussing points are called).

No NEX, Olympus, Fuji, and probably all other rmirrorless bodies have cross type focussing. If they did then you'd be able to focus on both horizontals and verticals, but you cannot, as you cannot focus on horizontals. DSLRs with cross type focus points still hold an advantage there, not sure how big that advantage is though.

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Chad Hardy
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Re: how can the NEX auto-focus miss these shots?
In reply to Sir Punk, 10 months ago

Set your autofocus to center spot, focus on the eye with half shutter press,  then recompose in frame and finish press.

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