Nex-7 AF exactly the same as 5N...complete miss AF...

Started Jan 8, 2012 | Discussions
LTZ470
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Nex-7 AF exactly the same as 5N...complete miss AF...
Jan 8, 2012

Really troubled by Sony's AF on the Nex System...Sony please fix this problem, you have an excellent camera and a great system with a very poor AF system...don't care if you hve to steal the technology from Panny & Oly, if they can get a FAST accurate AF you can too! Love the size of the 7 with 18-200 Tamron on...needs a better AF period...

Center AF Single Box...Spot Metering...Shutter Priority...1/320...ISO 3200...jpegs...

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technomad
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

Are you sure it's not a lens issue? I've just got my NEX-7 and 24mm Zeiss and went out to play yesterday - used the object tracking AF function to get this shot, tracking on the dog. For a compact system camera, I was blown away by its speed and reliability

Haven't tried similar with the 18-55 or 18-200mm yet.

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jalimb
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to technomad, Jan 8, 2012

wow nice!

technomad wrote:

Are you sure it's not a lens issue? I've just got my NEX-7 and 24mm Zeiss and went out to play yesterday - used the object tracking AF function to get this shot, tracking on the dog. For a compact system camera, I was blown away by its speed and reliability

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gfrensen
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

Looked at your pictures and a few things I see:
1. The kids are very low contrast, compared to the bascground

2. The background looks sharp to me (So it is an AF problem, not an lens problem)

Some tips to try:
Put of the focus assist light, focussing will go better

Remember that the camera can't tell what you wat to be in focus, so look close when focussing where the focus point is. (In this case it should be on your kids fases)

When the large AF rectangle appears instesd of the small boxes then go to MF (you can put the camera in DMF, so you can focus when the big box appears
Rememberr to only shoot when the focus is confirmed (green box)

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LTZ470
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to gfrensen, Jan 8, 2012

gfrensen wrote:

Looked at your pictures and a few things I see:
1. The kids are very low contrast, compared to the bascground

2. The background looks sharp to me (So it is an AF problem, not an lens problem)

Some tips to try:
Put of the focus assist light, focussing will go better

Remember that the camera can't tell what you wat to be in focus, so look close when focussing where the focus point is. (In this case it should be on your kids fases)

When the large AF rectangle appears instesd of the small boxes then go to MF (you can put the camera in DMF, so you can focus when the big box appears
Rememberr to only shoot when the focus is confirmed (green box)

Did all of that...it still back focused...AF Light was working...running some test as well against the G3 and EP3...just like I stated before AF on te Sony's is very poorly executed...while the G3 and EP3 have no issues at all...proof on the way..
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LTZ470
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to technomad, Jan 8, 2012

technomad wrote:

Are you sure it's not a lens issue? I've just got my NEX-7 and 24mm Zeiss and went out to play yesterday - used the object tracking AF function to get this shot, tracking on the dog. For a compact system camera, I was blown away by its speed and reliability

Haven't tried similar with the 18-55 or 18-200mm yet.

Great shot, but only one thing is different you were in bright sunlight and well lit subjects...shoot a few of you dog indoors and post those with just indoor lights alone...

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LTZ470
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

The camera is choosing wher it wants to focus...the Oly's can do this when shooting Macros and Close Ups...
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stabilo
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

Could it be that, only half of your kids face was in the focus rectangle, and the other half of the rectangle was the spring water? In that case, the camera has to make a choice on what to focus on, since there's two different "lengths" in the focus rectangle.

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TEBnewyork
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

What about face detection?

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LTZ470
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to TEBnewyork, Jan 8, 2012

TEBnewyork wrote:

What about face detection?

Excellent point Terry...let me try that...I can tell you this my G3 and EP3 are getting much tighter in my grip! With the prime lens on and shot wide open it's a no contest the m43 at ISO800 looks better than Nex-7 at ISO 640...
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gfrensen
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

LTZ470 wrote:

gfrensen wrote:

Looked at your pictures and a few things I see:
1. The kids are very low contrast, compared to the bascground

2. The background looks sharp to me (So it is an AF problem, not an lens problem)

Some tips to try:
Put of the focus assist light, focussing will go better

Remember that the camera can't tell what you wat to be in focus, so look close when focussing where the focus point is. (In this case it should be on your kids fases)

When the large AF rectangle appears instesd of the small boxes then go to MF (you can put the camera in DMF, so you can focus when the big box appears
Rememberr to only shoot when the focus is confirmed (green box)

Did all of that...it still back focused...AF Light was working...running some test as well against the G3 and EP3...just like I stated before AF on te Sony's is very poorly executed...while the G3 and EP3 have no issues at all...proof on the way..

But did you try it wit AF assist light OFF It is funny but ofthen AF gets better then.

Did you get the big focus confirm box or the small one? The big one confirms that focussing is done on the large picture, not on the focus point.

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seachicken2000
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

The camera seems to be focusing on the background rather than the subject.

The trick is to take away the camera's freedom to do so. My advice is to switch to flexible focus spot and either move it onto the subject or leave it in the center and focus then re-frame.

The flexible focus spot is very precise, and will give you control over what gets focused on. I have never had the focusing issue you're showing here on my NEX-5.

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Lars
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

I can confirm this (using single AF with centered AF field, no AF assist light). The Nex AF will focus on the area with higher contrast in the AF field - so if your AF area covers both an object with good contrast in the background and an object with poor contrast in the foreground, it will choose the background.

Face Detection might be a workaround.

At least make sure that your subject is covered fully with the AF field.

Another option would be to use DMF and focus assist.

I'd love to ability top make the focus area smaller.

Also, the AF is poor on horizontal lines and needs vertical lines to work well.

As hapy as I am with my 5N, the AF is neither great nor fast under less than ideal lighting.

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Helen
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to seachicken2000, Jan 8, 2012

seachicken2000 wrote:

The camera seems to be focusing on the background rather than the subject.

The trick is to take away the camera's freedom to do so. My advice is to switch to flexible focus spot and either move it onto the subject or leave it in the center and focus then re-frame.

The flexible focus spot is very precise, and will give you control over what gets focused on. I have never had the focusing issue you're showing here on my NEX-5.

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I second that (and some of the previous posts) - and the two points raised need to be combined: flexible spot or a single centre spot AF are more precise (which the OP doubtless already knows) - but also, as previous posters have said, results get better for being more controllable and predictable when the AF assist light is permanently disabled. When it is on, the camera defaults far too readily to a really wide focus area (basically all of the multiple points), as indicated by the wide focus box with dotted edges. Also, when the AF assist is available, the AF system gives up far too easily and will signal the inability to focus at all if can't find anything illuminated by the AF light, whereas with it turned off and aimed exactly the same way, it will very often hunt a little and then manage a lock (on the correct target, too).

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LTZ470
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to Helen, Jan 8, 2012

Helen wrote:

seachicken2000 wrote:

The camera seems to be focusing on the background rather than the subject.

The trick is to take away the camera's freedom to do so. My advice is to switch to flexible focus spot and either move it onto the subject or leave it in the center and focus then re-frame.

The flexible focus spot is very precise, and will give you control over what gets focused on. I have never had the focusing issue you're showing here on my NEX-5.

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A rose by any other name is still a chicken.

I second that (and some of the previous posts) - and the two points raised need to be combined: flexible spot or a single centre spot AF are more precise (which the OP doubtless already knows) - but also, as previous posters have said, results get better for being more controllable and predictable when the AF assist light is permanently disabled. When it is on, the camera defaults far too readily to a really wide focus area (basically all of the multiple points), as indicated by the wide focus box with dotted edges. Also, when the AF assist is available, the AF system gives up far too easily and will signal the inability to focus at all if can't find anything illuminated by the AF light, whereas with it turned off and aimed exactly the same way, it will very often hunt a little and then manage a lock (on the correct target, too).

Good point Helen I will try without AF assist as well..it was set to Auto...OK that cured my problem... TURN off AF Assist!!!! ...Much better...
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Helen
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to Lars, Jan 8, 2012

Lars wrote:

I can confirm this (using single AF with centered AF field, no AF assist light). The Nex AF will focus on the area with higher contrast in the AF field - so if your AF area covers both an object with good contrast in the background and an object with poor contrast in the foreground, it will choose the background.

Face Detection might be a workaround.

At least make sure that your subject is covered fully with the AF field.

Another option would be to use DMF and focus assist.

I'd love to ability top make the focus area smaller.

I've always missed this option in the NEX cameras, but have found a slight improvement with the 5N, at least - using the touch screen (but with focus tracking turned off as I find that a bit unpredictable), the box that appears on touching the screen (I have single, centre point AF selected most of the time, rather than flexible spot as it hijacks the bottommost customisable button) is both smaller than usual, as well as being placeable in numerous positions. It's effectively like an instant/temporary Flexible Spot AF, without losing your own customised setting on Button B.

Also, the AF is poor on horizontal lines and needs vertical lines to work well.

I've noticed that with several other brands too. Someone recently stated on a forum (don't remember which one) that CDAF shouldn't technically need to be limited to vertical lines and I can see why they say that, but it does typically seem to be.

As hapy as I am with my 5N, the AF is neither great nor fast under less than ideal lighting.

I agree with that - it's decent, but not as fast and sensitive as the latest Olympus models (though they do become more hesitant in low light without the AF light on), Panasonics, or the Nikon 1 cameras (which are near-instant in good light due to PDAF, and a shade faster in low light than the NEX).

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loicc
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Peaking can hel you in these situations.
In reply to LTZ470, Jan 8, 2012

You could activate the peaking.
It can help you to control if your subject is focused properly.

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LoMiTy
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Re: Nex-7 AF exactly the same as 5N...complete miss AF...
In reply to LTZ470, Jan 8, 2012

I've been getting great AF results with face registration of my kids and face detection. If I'm not taking pics of the kids and I have time then I often use DMF. With these two functions I almost never miss a shot. Thanks all for the AF assist lamp tip.

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blue_skies
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Re: Ok. this is from my (empirical) findings:
In reply to LTZ470, Jan 8, 2012

Below is what I discovered on the Nex-5N - which I believe is the same software algorithms as on the Nex-7.

Daytime: usually no problem

Lowlight: many issues

1.AF assist light on

  • focus is center weighted. If anything appears in the center, the focus is on the center object - often not you (people) subjects

2. iAuto / face detect

  • if peoples faces are visible (torso) and bright, the face detect focus is perfect. If the faces are small (people full size), or the background is bright, the face detect focus often misses, and another focus mode is applied.

3. Bright background

  • if anything bright is in the picture, the focus point seems to be at the leftmost transition from dark to bright, with the focus on the bright spot

  • eg. the fountain is in perfect focus, the children are not

4. Flash mode

  • turning on the flash does not change the AF algorithms. In addition the flash is often over saturated as is changes the metering mode. Turn on flash compensation to -1.3EV or something like that. Even if (indoor) bounce.

How I increased my lowlight (especially indoors) keeper rate:

A. Turn off AF assist

  • the daytime algorithms maintain themselves, and you are very sensitive to aforementioned problems. But bright faces in darker background are in focus. Standing people in dark clothes often are not.

B. Forget iAuto

  • use A mode or P mode. In A mode, select widest aperture, in P mode select slow shutter speed. Auto ISO will (always) select 1600 (for Nex-7) and 3200 (for Nex-5N), unless flash is on.

C. Change AF mode to DMF or MF

  • verify focus manually by rotating the focus ring on the E-mount lens.

  • if multiple pics, use MF: you only have to adjust the focus a little, and focus is held

  • (in DMF mode, the AF algorithm is still throwing the focus off, each time you are not halfpressing the shutter button)

D. Get a faster lens

  • it helps a little with AF, but moreover, the MF gets to be a lot easier. Under proper (indoor lighting) condition, you will even see focus peaking

  • make sure focus peaking is turned on and set to low

E. People shots / face detect

  • the face detect focus on peoples faces is actually very good and works well.

  • if you compose a shot of people torso's (e.g. from across the table) AND the faces are well lit (light on their faces), you can turn on face detect and use AF, or DMF, (3), but leave iAuto (1) and AF assist (2) both off; you will now see two small squares around the two faces, one on each person. If so, your focus is good. If no two small squares are visible, do not use AF, but use DMF, or MF to find focus.

Below some people pictures to illustrate above. These pictures were all without flash under extreme lowlight. OOC, they were actually underexposed, used LR3 to fix. In fact, the pictures shown below suggest that lighting was brighter than it actually was - see the EXIF data.

  • (images are downsampled to 2Mp)

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DezM
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Same thing
In reply to LTZ470, Jan 8, 2012

Yes Sony, please fix this problem. I've had issues with AF on my NEX-5N as well. Whether it be in normal light, low light or with flash. In daylight, it's ok.

The NEX tends to backfocus or focus on objects brighter than the subject, even though you have the AF point (Center AF or Flexible Mode) on your subject. I also had issues with Xmas tree lights, a few weeks back.

My troubles:
http://forums.dpreview.com/forums/read.asp?forum=1042&message=40162407
http://forums.dpreview.com/forums/read.asp?forum=1042&message=40166889

Now, I use Focus Peaking with MF Assist. That's a solution for now, but the AF isn't acceptable and that's why I sent my kit (body and 18-55mm lens) back to Sony's Service Center a couple of days ago. I'm hoping for a repair or an exchange.
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