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Thread: Front focussing on A7rII and certain lenses

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    Front focussing on A7rII and certain lenses

    A thread has been started on preview that at first I didn't take seriously
    Returned A7R II because of severe frontfocus: Sony Alpha Full Frame E-mount Talk Forum: Digital Photography Review
    But then I got to thinking and I notice that the A7rII opens up the aperture to focus which isn't the case on my A7s and I don't have the A7 or A7II anymore to check. On doing some testing with the FE24-70 at 50mm on a tripod etc I do in fact seem to be noticing a shift forwards and I can only presume that if the lens didn't open up to focus wouldn't be there. Now I only have the A7s to compare it with and it is only 12mp so I can't really get an accurate comparison ( when tested in the same way I can't see any shift) with something similar nor do I have a proper test chart that I can place at 45 degrees to see what is really going on. So it would be good if others could test this out. Thanks

    P.S tested on the FE16-35, 55 and 28 and they are all fine with the focus point getting sharper as you stop down which certainly doesn't seem to be the case with the 24-70
    Last edited by Viramati; 23rd August 2015 at 10:35.

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    Re: Front focussing on A7rII

    Is it camera "front focusing" or lens having aperture dependent focus shifts that creates this problem?

    Can you check with other lenses if this is the case?


    PS: Just saw your PS. It is the 24-70 zoom, me thinks.
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    Re: Front focussing on A7rII

    Quote Originally Posted by Vivek View Post
    Is it camera "front focusing" or lens having aperture dependent focus shifts that creates this problem?

    Can you check with other lenses if this is the case?


    PS: Just saw your PS. It is the 24-70 zoom, me thinks.
    I agree and would be interesting if someone could test the FE24-70 on an A7r or even A7. On the A7s it seems fine

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    Re: Front focussing on A7rII and certain lenses

    I am glad the guy started that thread. After some initial bickering it now has some useful content.
    With best regards, K-H.

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by k-hawinkler View Post
    I am glad the guy started that thread. After some initial bickering it now has some useful content.
    I agree though I trust people her more to get to the bottom of it. Personally I am not that worried as I would probably never use the 24-70 on the A7rII as I really don't feel it is up to the 42mp sensor and have only kept it as it performs so well on the A7s and if I sell that the 24-70 will go as well.
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    Re: Front focussing on A7rII and certain lenses

    I would request anyone testing the FE 24-70 on A7r or A7 to try turning 'Setting Effect' to OFF in the 'Live View Display' menu to see if this make s matters worse as I am not sure if in this mode the camera focuses first and then stops down. Thanks

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    Re: Front focussing on A7rII and certain lenses

    If I get a chance I'll test it with a Spyder tomorrow. I wouldn't assume, though, that it is necessarily quite as simple as 'it opens up to focus'. On the RX1 it does different things depending on what aperture range you are in - that camera always focusses (and therefore previews) at the selected aperture for all apertures from F2 thru F8 BUT from F9 thru F22, it will open up to F8 for AF. So from F9-22, if you look at the preview while the camera is performing AF, you will get an inaccurate representation of DOF.

    To compound the potential confusion, when I look into the lens barrel on the 24-70 f4 on the A7RII it looks as if the camera is opening up to focus, but there is also a hint that it does its first round of focus wide open, then stops down to maybe refine it even after the beep. This might be switching between PD and CD systems? It might also depend not only on whether you have settings effect on or off, and it might be affected by the balance between accuracy and speed you have set. Also, try pointing the camera at a featureless thing that it can't focus on and watch it's little aperture ring going in and out like a fish's mouth.

    Of course what matters is that it works, which it should, so I will give it a go and report back. The last thing one wants to do is to have to remember how the camera is behaving in terms of focus according to several different combinations of settings but to some extent, as they open up all these choices, that's gonna happen...
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    I would request anyone testing the FE 24-70 on A7r or A7 to try turning 'Setting Effect' to OFF in the 'Live View Display' menu to see if this make s matters worse as I am not sure if in this mode the camera focuses first and then stops down. Thanks
    I have tested this on my A7R when I briefly had the 24-70/4 OSS. I tested Eye-AF with Elinchrom Skyport trigger with manual flash so it must have been with "Setting Effect off". I've reported this even here before but the AF accuracy was not good, I would not say massive focus errors, but enough to know that AF was a bit off. One of the main reasons my 24-70/4 OSS went back shop, only lens I've ever returned.

    I actually still have the shots in my LR Catalog and I still can still super-easily pick the OOF 24-70/4 shots from FE 55 shots I shot for comparison and this was at F/5.6. The best shots I got with 24-70 were manually focused.

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    Re: Front focussing on A7rII and certain lenses

    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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by davidstock View Post
    I'm interested in this issue, too.

    And what happens when you use back button focus?

    --d
    Seems to function in exactly the same way

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by tn1krr View Post
    I have tested this on my A7R when I briefly had the 24-70/4 OSS. I tested Eye-AF with Elinchrom Skyport trigger with manual flash so it must have been with "Setting Effect off". I've reported this even here before but the AF accuracy was not good, I would not say massive focus errors, but enough to know that AF was a bit off. One of the main reasons my 24-70/4 OSS went back shop, only lens I've ever returned.

    I actually still have the shots in my LR Catalog and I still can still super-easily pick the OOF 24-70/4 shots from FE 55 shots I shot for comparison and this was at F/5.6. The best shots I got with 24-70 were manually focused.
    What I am seeing is not AF inaccuracy because if I focus manually on an object take the shot wide open and then stop down I 'think' I am seeing the same shift. So I am concluding that when focussing with the lens stopped down on previous models this compensates for any focus shift. As I said I am unable to test anything on the A7s as the resolution would seem not to be enough to pick up any problems

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by davidstock View Post
    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?
    I only have the 55 FE native lens (just got the camera), but as far as I can tell when you hit the back button AF the camera opens up to almost f/1.8 (but definitely not f1.8) and then gradually closes down the aperture as you achieve focus lock. The closing of the aperture does not occur instantly, and the camera may be pausing/slowing down as the aperture blades close (to recheck focus?).
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by sbay View Post
    I only have the 55 FE native lens (just got the camera), but as far as I can tell when you hit the back button AF the camera opens up to almost f/1.8 (but definitely not f1.8) and then gradually closes down the aperture as you achieve focus lock. The closing of the aperture does not occur instantly, and the camera may be pausing/slowing down as the aperture blades close (to recheck focus?).
    Yes, A7R II works this way, normal and back-button AF. My F/1.8 lenses (FE55 and Batis 85) open up to around F/2 or F/2.2 regardless of shooting aperture. My theory is that PDAF likes the wide open and then CDAF is used to confirm while stopping down. Although the lenses know their focus distance etc. so there could be focus-shift database in the camera and the gradual stopping down is just to avoid any sudden changes of brightness in the EVF. I tested this while looking at the aperture blades in think I heard focus confirm beef before aperture blades stopped down.

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by sbay View Post
    I only have the 55 FE native lens (just got the camera), but as far as I can tell when you hit the back button AF the camera opens up to almost f/1.8 (but definitely not f1.8) and then gradually closes down the aperture as you achieve focus lock. The closing of the aperture does not occur instantly, and the camera may be pausing/slowing down as the aperture blades close (to recheck focus?).
    That's my current guess too, and tomorrow I'll have look at that happens when you change your focus preference settings in Cog>4 but I have to say that there are so many permutations that before we all start testing we need to think about what the possible variables are and then test around that knowledge.
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    Re: Front focussing on A7rII and certain lenses

    So someone else on the dpreview thread has confirmed my suspicions and with the 'setting effect' set to OFF in the live view display on an older A7 he has replicated the issue with the 24-70. So if this is the case a solution would be to give us the option be able to disable the shutter from opening up during focusing. How to communicate these findings to Sony is another matter as I remember how difficult I found it trying to get through to anyone technical when I discovered the IBIS issue withe A7II and adopted lenses

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by tashley View Post
    That's my current guess too, and tomorrow I'll have look at that happens when you change your focus preference settings in Cog>4 but I have to say that there are so many permutations that before we all start testing we need to think about what the possible variables are test around that knowledge.
    I agree. Another complication, mentioned by others, is that that Sony may encode the lens characteristics (including focus shift) to achieve better focus. If this encoding is not working, that might cause problems in limited cases. (If there is encoding, does it apply to Zeiss FE lenses, too? And what happens with adapted A-mount lenses....)

    It might help to know which FE lenses are known to have focus shift. According to photozone, the 70-200 f4 does have some. On the other hand, based on its MTF chart, I doubt that the 55 Zony has any. With the 35mm f2.8, the shift looks minimal. Given what we've just heard about the 24-70 zoom on the A7, that lens does have noticeable shift. I wonder about the 85 Batis and the 35mm/1.4?

    --d
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    Re: Front focussing on A7rII and certain lenses

    I had a similar problem on the A7S and the FE 35/2.8 right after I loaded the latest firmware. Every time I tried to focus i saw the green focus lock box but it looked like I was doing a bokeh test with nothing in focus. I had the camera on either wide or zone focus mode, I can't remember which, but to fix I had to swap to the center focus mode. Now that's the focus mode I will use on the FE 35/2.8.

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    Re: Front focussing on A7rII and certain lenses

    Just to double check the issue again I have retested the FE24-70 on my A7s with 'display live view' 'setting effect' on and Off and with it off there is definite focus shift with the setting set to off so I am now convinced that this is an issue of the lens not being stopped down when focussing takes place.

    I have also once again tried contacting Sony this morning and I can see that it will be a long and tedious process so if any of you reading this have some access to Sony that would be so helpful. I had thought of trying to contact Micheal at LuLa as he has just tested the camera and may have some Sony contacts

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    Just to double check the issue again I have retested the FE24-70 on my A7s with 'display live view' 'setting effect' on and Off and with it off there is definite focus shift with the setting set to off so I am now convinced that this is an issue of the lens not being stopped down when focussing takes place.

    I have also once again tried contacting Sony this morning and I can see that it will be a long and tedious process so if any of you reading this have some access to Sony that would be so helpful. I had thought of trying to contact Micheal at LuLa as he has just tested the camera and may have some Sony contacts
    I have tested it today with a Spyder Lens cal target, specially made for this sort of exercise.

    Distance from focal plane to centre of target: 2.25 metres.

    Tripod, delay, you name it.

    Settings effects and so on all off
    preferences in Cog>4 set to focus, rather than balanced priority.

    First I tried with the camera set to MF and I focussed carefully at F4 at 50mm and 70mm and for each focal length I then stopped down to 5.6 and 8 without changing focus. This is intended to see if there is any significant focus shift inherent in the lens regardless of AF. IMHO though there probably is, it isn't significant enough to outstrip DOF at any of the tested focal lengths other than 70mm.

    At 70mm it is clear that when focussed manually (I ran several series) the lens shifts focus forwards as it stops down, such that DOF is not enough to save it until F11. In other words, the POF is in less good focus at 5.6 and 8 than at F4.

    Switching to AF (and again I ran several series) I had no problem at any focal length other than 70mm where I discovered two things: firstly, that exactly as with MF, the AF series saw focus shift forward such as to require F11 to achieve sufficient DOF to beat that shift and secondly, that the lens tends to front focus anyway, even at F4.

    It certainly has the plane of focus within DOF but rather towards the back of that DOF, and therefore as the lens goes on to shift focus forward with smaller apertures, the effect of that focus shift is working with the natural front focus tendency to make focus just plain inaccurate at 70mm and F5.6 and F8 and barely satisfactory at F4 and F11.

    I'd like to run these tests again now that I have a sense of what's going on but the light has gone now.

    I think this should be easy to fix, assuming that anyone at Sony can be encouraged to pay attention. There's a whole lot of electronics governing where and how the lens focusses and a firmware update should deal with it.

    But for now, at least at 70mm (and I want to test at 60 and 65mm) I think one has to shoot at F4 and put up with the limited DOF, or at F11 and put up with diffraction, or use DMF, or, more easily, just choose the furthest back part of the subject. Will eye AF work at 70mm and f5.6 or f8? I'll have to test that but I wouldn't bet on it.

    EDIT: I have to add that the more cameras and lenses I own and test, the more I realise that one can only ever speak for a particular copy of a lens on a particular copy of a camera. YMMV.
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    Re: Front focussing on A7rII and certain lenses

    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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    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

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    Re: Front focussing on A7rII and certain lenses

    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.
    Bart ...

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Knorp View Post
    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.

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    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 ...
    Bart ...

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    Re: Front focussing on A7rII and certain lenses

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

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    Re: Front focussing on A7rII and certain lenses

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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by dandrewk View Post
    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

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    Re: Front focussing on A7rII and certain lenses

    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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by dandrewk View Post
    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 - - -

    Quote Originally Posted by Viramati View Post
    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.
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    Re: Front focussing on A7rII and certain lenses

    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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    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...

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    Re: Front focussing on A7rII and certain lenses

    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.
    Last edited by anGy; 25th August 2015 at 04:36.
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  33. #33
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by anGy View Post
    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 ?
    Bart ...

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Knorp View Post
    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

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    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.

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    Re: Front focussing on A7rII and certain lenses

    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
    David
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by davidstock View Post
    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

  38. #38
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    Re: Front focussing on A7rII and certain lenses

    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]

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    Re: Front focussing on A7rII and certain lenses

    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.

  40. #40
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    Re: Front focussing on A7rII and certain lenses

    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

  41. #41
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    Re: Front focussing on A7rII and certain lenses

    I have just done a very quick check with the new FW and the FE 35/1.4 in very low light. With the lens stopped down and using the back button AF I clearly see and hear that there is a first step in which the lens open up (not fully, probably just at f:2) to help focus and then closes again at the selected opening. I do not know if the complete AF routine or just the first step is performed with the lens wide open.

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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by davidstock View Post
    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
    From how I see my FE24-70 is behaving this would make sense as the aperture iris now seems to stay stopped down when focussing. On the FE55 it still opens up fully. haven't tested the FE16-35. I guess they have had to fix it at the expense of low light focus speed if stopped down but personally I would be tending to shoot these lenses wide open in low light so performance should remain the same

  43. #43
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by Viramati View Post
    From how I see my FE24-70 is behaving this would make sense as the aperture iris now seems to stay stopped down when focussing. On the FE55 it still opens up fully. haven't tested the FE16-35. I guess they have had to fix it at the expense of low light focus speed if stopped down but personally I would be tending to shoot these lenses wide open in low light so performance should remain the same
    There is a workaround for focusing problems in low light, which I use quite often with the A7r : I have ISO set to the four ways controller wheel, so it is just a small rotating move of the thumb to get much higher ISO, focus and then with a reverse move of the thumb you return to the wanted ISO.

    I know that many don't like keeping something on that wheel, out of fear they could accidentally change their settings. But I rarely have that problem, so I keep it active and it is very handy for quick changes.
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  44. #44
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    Re: Front focussing on A7rII and certain lenses

    Quote Originally Posted by tashley View Post
    I have tested it today with a Spyder Lens cal target, specially made for this sort of exercise.


    EDIT: I have to add that the more cameras and lenses I own and test, the more I realise that one can only ever speak for a particular copy of a lens on a particular copy of a camera. YMMV.
    OMG...... how true!!

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