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Focusing issues with A7 III and Sony lenses

Antonio Correia

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I am having some bit issues with the focus using my A7 III. It doesn't focus as precisely as I wish or rather where I wish !

The second shot was a bit more difficult to focus than the first one. I was near and with the 135mm which returns a very shallow DoF at that distance.

In the first one, the surface was rather flat and focus was easily obtained while on the second one I had to focus manually to reach the point I wanted or... the point I wanted to be in focus.

If you look closely, you will find the end of the stick in perfect focus while I wanted the big, large orange form in focus.
The focus peaking is at it' s minimum and many points were on, dancing around. I do not understand was is going on or how its is going on.
I have used before a Canon 5D with red ring lenses and I had never this kind of problem. The focusing was not so sophisticated indeed...

I then moved to Olympus (5 Mk II) with primes and zooms and everything was OK.
Today, I shot with Olympus in the morning and with Sony in the afternoon.
I have a worst rate of success with the Sony than with the Olympus. Shame on me !

OK, OK I know: "Don't blame the camera blame yourself"

I think it is the choice of the focus area I have to learn about.
It is just that I am sad. And so my wife is, because she is having the same problem with the 6500.
Well... let's move on.

And ideas ? I am already reading about the focus area, focus points and so on...

Have a good Sunday ! Cheers !

ILCE-7M3    FE 24mm F1.4 GM    24mm    f/4.0    1/400s    ISO 100

ILCE-7M3    FE 135mm F1.8 GM    135mm    f/2.0    1/1600s    ISO 100
 

lew

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Seems to me that this is a problem with "auto" focus in general. How did your Canon "know" where you wanted to focus? Were the dof and subject plane issues the same as these shots?

I find that, for shots like these, "auto" just wastes too much time. Either turn it off or use any of the many, many great non-auto lenses via adapter & save the weight of these monsters.
 

Antonio Correia

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Thank you Lew fro your kind comment !
The thing is that I now have these monsters and intend to keep them !
However, your option - the use of old lenses like Nikon from 1972 (which I also have) or Canon (12 or 15 years old) - is much valuable and it really is an excellent option.
Cheers ! :)
 

Drd1135

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I just use single point AF. I either keep it center, focus and recompose OR move the focus point using the joystick. Especially good for static subjects like this.
 

WNG

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I think you have it set to AF-C wide focus area, therefore it will look for a foreground object and the dancing green boxes gives you a false sense of focus on your intended subject. This setting is better for far field shots where DOF of using a large aperture is less apparent.
You can switch it to either AF-S with a center flexible spot, or AF-C with the same reduced focus flexible spot. Instead of focus and compose, use the joystick to quickly drag the spot in your composition to your intended subject. Then it will snap focus to it.
 

Drd1135

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I think you have it set to AF-C wide focus area, therefore it will look for a foreground object and the dancing green boxes gives you a false sense of focus on your intended subject. This setting is better for far field shots where DOF of using a large aperture is less apparent.
You can switch it to either AF-S with a center flexible spot, or AF-C with the same reduced focus flexible spot. Instead of focus and compose, use the joystick to quickly drag the spot in your composition to your intended subject. Then it will snap focus to it.
What he said.
 

Antonio Correia

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Will, Steve and Mike thank you so much for your constructive comments and help.
I already know the videos, pdf(s) and even his spreadsheet table about the settings of this camera.
I am going to go over them again and I will try by myself.
In fact, yesterday and today I spent some time playing around and I think I will find my way.
Thank you again ! :)

ILCE-7M3    FE 24mm F1.4 GM    24mm    f/5.6    1/800s    ISO 100
 

Ziggy99

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I don't find the AF on the A9 very reliable.

Using Spot there can be the green confirmation when nothing is locked. Using Zone there can be green dancing boxes when focus is soft.

This is with CAF in single or burst mode on still and moving birds.

The difference from my Nikon D500 is noticeable. If it performed in the same way I'd be blowing out the AF sensor.

I put it down to the use of line-type sensors rather than cross-type but I really don't know. Thom Hogan says on-sensor AF is still not quite as accurate as that with a separate sensor.

More here - https://www.talkemount.com/threads/a9-focus-fails.19467/#post-162359
 
Last edited:

Antonio Correia

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I don't find the AF on the A9 very reliable.
Using Spot there can be the green confirmation when nothing is locked. Using Zone there can be green dancing boxes when focus is soft.
This is with CAF in single or burst mode on still and moving birds.
The difference from my Nikon D500 is noticeable. If it performed in the same way I'd be blowing out the AF sensor.
I put it down to the use of line-type sensors rather than cross-type but I really don't know. Thom Hogan says on-sensor AF is still not quite as accurate as that with a separate sensor.
More here - https://www.talkemount.com/threads/a9-focus-fails.19467/#post-162359
Thank you for commenting Ziggy99. :)
In the last days I have been working on the focusing settings trying to get one or more solutions. I have been watching videos, reading and so on.
I would say that the focusing system is not simple.
The dancing green squares are very confusing which lead me to the bad result previously posted.
But I hope to reach a point where I can make nice and perfect focus. I hope ! :laugh:
Cheers ! :)
 

Ziggy99

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Yes.
There's the question of what parts of a scene get focus preference in the algorithms, and how CDAF and PDAF are used. Sony doesn't talk about the latter but we might expect that a focus lock that's soft arises out of PDAF only.
The last time I had regular failure to lock was with the Panasonic G9 that only had CDAF.
 

Antonio Correia

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You talk too technical to me Ziggy :)
When using the Olympus 5 II with the 7-14 lens I had most of the shots in focus, if not all.
The same was happening with when using the other lenses I still have from Olympus and Panasonic. The success rate was far superior to when using this expensive camera and lenses.
I was using the 7 with the 24mm in Guatemala last month and a lot of shots were missed ! OK. My problem who doesn't know how to work with a sophisticated camera !
I am working on it !
This is a simple shot without any difficulties whatsoever !

ILCE-7M3    FE 24mm F1.4 GM    24mm    f/4.0    1/125s    ISO 200
 

Ziggy99

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Thanks.

I spent a lot of time shooting birds with the Pana G9 and ended up giving it up cos of a relatively poor keeper rate, and I disagree with Undone's judgment.

Sometimes with a perched bird it would simple not lock on the bird but on what was behind it (the pro advice was to find a contrasty line to focus on and often that had to be its edge). With a BIF in mid distance and busy background it would usually get the background.
CDAF works on the principle that the closer to focus an area is the greater will be the contrast between adjacent pixels. But if you have say 150 AF points, which are going to be taken into account when determining this; ie. what is the subject? Some PDAF systems clearly preference what's closest (eg Nikon DSLRs) but the G9's CD clearly preferenced what was further away. That could work for you in some contexts but not in others.

Closer to home, the question is how Sony deploys its two. Ideally, as Undone outlines, start with PD for speed and finish with CD to get the subject as sharp as possible. Can the Sony do this at 10 or 20 fps? It takes a lot of number crunching and a lot of fine lens movement at the end. When I look at a burst series, I see more shots that are just a little soft cp my Nikon and its PDAF.

And complete failures with simple static birds or other subjects; this was closest, contrasty and in good light, and in the centre of the AF area. No lock was recorded in the EXIF data.

ILCE-9       840mm    f/9.0    1/1000s    ISO 1000
 

WNG

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Thanks.

I spent a lot of time shooting birds with the Pana G9 and ended up giving it up cos of a relatively poor keeper rate, and I disagree with Undone's judgment.

Sometimes with a perched bird it would simple not lock on the bird but on what was behind it (the pro advice was to find a contrasty line to focus on and often that had to be its edge). With a BIF in mid distance and busy background it would usually get the background.
CDAF works on the principle that the closer to focus an area is the greater will be the contrast between adjacent pixels. But if you have say 150 AF points, which are going to be taken into account when determining this; ie. what is the subject? Some PDAF systems clearly preference what's closest (eg Nikon DSLRs) but the G9's CD clearly preferenced what was further away. That could work for you in some contexts but not in others.

Closer to home, the question is how Sony deploys its two. Ideally, as Undone outlines, start with PD for speed and finish with CD to get the subject as sharp as possible. Can the Sony do this at 10 or 20 fps? It takes a lot of number crunching and a lot of fine lens movement at the end. When I look at a burst series, I see more shots that are just a little soft cp my Nikon and its PDAF.

And complete failures with simple static birds or other subjects; this was closest, contrasty and in good light, and in the centre of the AF area. No lock was recorded in the EXIF data.

View attachment 106106

To be frank, I really can't see any static bird in that missed AF shot in the frame. :-\
 

Ziggy99

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It was set on full.
The 200-600 has 3 settings. The obvious one for forest birds is the middle one but who can reliably distinguish between 9 and 11 metres?
I've repeated the test in two other contexts with the 100-400 and 1.4x TC - same deal.
If certain conditions apply swapping to Zone may work better: bird in the centre, closest to the camera, and/or in a contrasting colour.
 

crazy150

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You talk too technical to me Ziggy :)
When using the Olympus 5 II with the 7-14 lens I had most of the shots in focus, if not all.
The same was happening with when using the other lenses I still have from Olympus and Panasonic. The success rate was far superior to when using this expensive camera and lenses.
I was using the 7 with the 24mm in Guatemala last month and a lot of shots were missed ! OK. My problem who doesn't know how to work with a sophisticated camera !
I am working on it !
This is a simple shot without any difficulties whatsoever !

I know this is a bit old thread, but coming from olympus myself I might add a few thoughts. First of all, the depth of field on the MFT cameras is much higher and therefore the autofocus system has much more room for error. For example, the 7-14 lens you mention even at F2.8 and 14 mm will have a massive dof at a "normal" subject distance so the chance of a missed focus is pretty small. As you can see that in the image of the flower, in just a cm or two behind stuff is out of focus so there is no room for error. I'm still waiting on my A7III, but generally autofocus goes to the nearest element in the focus zone which is probably why you got focus on the end of the stick instead of the flower.

You should try the two cameras in similar situations before you judge one harshly.
 
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