Front focussing on A7rII and certain lenses

[tashley]

Thanks Tim for your testing. I understand that there could well be lens variation involved here. I di the testing on mine at 70, 50 and 35mm all with similar results.
i have sent an email of my findings to Sony and will try to see if my dealer has some way of contacting them more directly.

P.S Tim if you have a previous version of the A7 try testing with the setting effect on and off in AF

Hi David,

I'm afraid the A7RII is the only one I have these days...

When you say similar results, do you mean similar to mine or similar results on yours between all focal lengths? If the latter, what was your shooting distance?

Best
Tim

 

[Knorp]

Do I understand correctly with Setting Effect to ON there is no front focusing (focus shift) ?
Or is that just to be tested and confirmed yet ?

TIA

Kind regards.

 

[Viramati]

Do I understand correctly with Setting Effect to ON there is no front focusing (focus shift) ?
Or is that just to be tested and confirmed yet ?

TIA

Kind regards.

Yes at least it would appear to be that way with previous models of the A7 series, the difference being that the RII opens up the shutter iris to focus even with the setting effect on so the shift doesn't appear to be compensate for.

 

[Knorp]

Yes at least it would appear to be that way with previous models of the A7 series, the difference being that the RII opens up the shutter iris to focus even with the setting effect on so the shift doesn't appear to be compensate for.

Aha - thank you, David. I think I've got it now ...

 

[dandrewk]

I've always had the setting effect set to "on". I've never had a reason to do otherwise.

 

[tashley]

I'll test again with settings effect on...

 

[Viramati]

I've always had the setting effect set to "on". I've never had a reason to do otherwise.

So have I but I will say again the on the A7rII it doesn't mitigate any focus shift issues as the iris opens up fully to focus unlike previous models. Basically if the lens remains stopped down that the AF will hit correct focus at the shifted point

 

[Viramati]

Very clear article here
https://photographylife.com/what-is-focus-shift
which I believe really explains what is going on. I imagine that because of the new extended PDAF system the lens needs to open fully which is exasperating the problem.
Maybe an option to turn PDAF with certain lenses would solve the problem

 

[Vivek]

I've always had the setting effect set to "on". I've never had a reason to do otherwise.

Mount a flash and you would need to the change settings effect to "off" to achieve higher shutter speeds.

- - - Updated - - -

Very clear article here
https://photographylife.com/what-is-focus-shift
which I believe really explains what is going on. I imagine that because of the new extended PDAF system the lens needs to open fully which is exasperating the problem.
Maybe an option to turn PDAF with certain lenses would solve the problem

This could be the first major bug. It should have shown up with the A7 II as well.

 

[Viramati]

Vivek unfortunately it may not be so much a bug but a necessity of the upgraded PDAF system and as such how it can be sorted for a lens that focus shifts becomes a bit more of a problem. I can hardly see Sony wanting to admit a problem with the FE24-70 and having to turn off PDAF to make it work and again I don't know if a firmware update can help the lens. In reality the problem with this lens has probably always been there but it just hasn't been noticed as most people probably work with display 'setting effect' in the ON position and as I have demonstrated with my A7s this solves the problem. The problem now is trying to communicate this to Sony

 

[tashley]

Vivek unfortunately it may not be so much a bug but a necessity of the upgraded PDAF system and as such how it can be sorted for a lens that focus shifts becomes a bit more of a problem. I can hardly see Sony wanting to admit a problem with the FE24-70 and having to turn off PDAF to make it work and again I don't know if a firmware update can help the lens. In reality the problem with this lens has probably always been there but it just hasn't been noticed as most people probably work with display 'setting effect' in the ON position and as I have demonstrated with my A7s this solves the problem. The problem now is trying to communicate this to Sony

I just re-ran a very quick test with settings effect on and though it was fine at 65mm, there still seemed to be a slight shift forward between f4 and f5.6 at 70mm, cured by F8 by DOF.

To really bottom this out I'd need to shoot many many series with many different menu configurations and permutations and sadly I don't have time right now....

My takeaway is that until I've bottomed it out, at 70mm I will use DMF if the shot matters...

 

[anGy]

I've noticed this front focussing problem with my A7RII & 35mm f1.4 as well.
Even at 7m focus distance and f4 I can achieve better sharpness in Manual focus than in AF.
The focused target is at the end of the field of focus with AF and appears a bit softer than with MF.

ps: on another test the focus mask in Capture 1 quite clearly shows that the picture I took with AF has a focus zone that is more in front compared to the manual focused shot. Again, although the target is not out of the focused zone with AF it is still out of the 'sharp focus' zone.

Not good but still to test so far.

psII: it is not possible to adjust the AF zone in the camera menu for the Sony lenses, in case someone asks.

 

[Knorp]

psII: it is not possible to adjust the AF zone in the camera menu for the Sony lenses, in case someone asks.

So, if we were allowed by Sony to use menu-option "AF-micro adj" for other lenses than A-mount only, we could be fine ?

 

[Viramati]

So, if we were allowed by Sony to use menu-option "AF-micro adj" for other lenses than A-mount only, we could be fine ?

Not sure if that could help as focus is spot on with the 24-70 when shot at f4 and only shifts as you stop down

 

[tashley]

Not sure if that could help as focus is spot on with the 24-70 when shot at f4 and only shifts as you stop down

I think it would help mine, which at 70mm, carries all of its DOF forward at F4 and could safely be tuned back just a touch, which would then make a big difference as it stops down.

 

[Viramati]

By the way I have an email into sony technical about this and received a reply that the issue has been 'escalated of further investigation'!!
Have also provided them with a link to this thread

 

[Viramati]

I'm interested in this issue, too.

I just started this thread on focus shift at DPReview:http://www.dpreview.com/forums/post/56363973

One of the things I like about my A7II is that it can easily focus with the lens stopped down to taking aperture. This avoids issues with focus shift that are somewhat common with SLRs. In fact, this is one of the reasons I transitioned to mirrorless cameras.

I am hearing from owners of A7RII cameras that the new camera's aperture opens up to focus, then stops back down to taking aperture, just like an SLR. This is a change from what the other A7 cameras do, AFAIK. I am wondering if this is causing any issues with focus shift.

Two things piqued my interest in this question recently. One is a review of the Batis 85mm lens on Luminous Landscape. In a series of photos of a truck, carefully focussed by Michael Reichmann using an A7RII on a tripod, there is clear evidence of front focus when the Batis is stopped down. Also, there have been at least four reports of zoom lenses front-focussing with the new camera. (example: http://www.dpreview.com/forums/post/56362175).

I wonder if others have experienced focus shift with any lenses on the A7RII, or are these reports just statistical outliers? Maybe just bad lenses?

I would be very curious to know if the A7RII opens the lens aperture part way or all the way in order to focus?

If it just opens up to f3.5 or so, this would probably eliminate most of the potential problems with focus shift. If it opens to f1.8 or f1.4 to focus, that seems to be inviting focus shift with lenses that are prone to it.

In that case, we would be back to where we were with SLRs--making sure our lenses have no focus shift, or else managing the shift as best we can.

Finally, I wonder what the A7RII's behavior is when back-button focus is used. Does the aperture still open up to focus when the camera is in this configuration?

Thanks for any information or insights.

-- hide signature --
d


In thinking this over, I'm realizing that most focus shift is to the back, not the front. So maybe these reports are unrelated to aperture behavior.

Still, I'd love to know from A7RII users here if the aperture actually opens up all the way to focus, or just part way. And what happens when you use back button focus?

--d

I went into my dealer yesterday to compare how the A7rII behaves compared to the A7II and noticed that the A7II seems to open the aperture partially while focussing while the A7rII goes all the way

 

[Viramati]

If anyone feels the need to contact Sony customer support because they too have discovered the issue here is the case number and email number for my report to them
[case:13085220]
[email:306649835]
the email address I contacted is
[email protected]

 

[Viramati]

Wow they listened as version 1.1 seems to have cured the issue

This utility updates the ILCE-7RM2 system software to version 1.10, and provides the following benefits:
Reduces the chance of the camera changing to front focus when shooting certain scenes.
Note: This symptom rarely occurs.
Decreases chroma noise when Long Exposure NR (Noise Reduction) is set to Off.
Note: The noise does not occur when Long Exposure NR is set to On.
Improves continuous shooting at Hi speed so that it can be used as long with the flash as without the flash.

 

[davidstock]

Did anybody check your low-light autofocus with the new firmware?

There's just been a report on DPReviews that low-light autofocus is degraded, at least with some lenses that previously showed focus shift and some non-native lenses.

There is speculation that this is because the A7RII aperture behavior that allowed focus shift (focus wide open, then stop down) has been changed, and that the new behavior allows less light onto the sensor during autofocus. In other words, camera aperture behavior is back to the previous A7 cameras. (Focus at taking aperture.) I can't vouch for this myself. Maybe a false alarm. But maybe worth checking?

--d