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Thread: A7R II Auto Focus Evaluation

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    A7R II Auto Focus Evaluation

    All you brave and lucky early adopters have generously shared many images and comments on this exciting new camera. I understand that for some of you manual focus is all that's necessary. However if autofocus performance is something you value I would greatly enjoy hearing about it. The few reports coming out haven't been definitive or precise. I surmise that the tracking capability is greatly enhanced. That's great to hear. My particular question is this:

    How accurate is the AFS on static targets? The reason I ask is that I have always considered the A7 (and NEX) autofocus too susceptible to missing focus. If I get the AF confirm indicator and then use manual magnification to check the focus there is a very high probability that the focus is poor. That is the one thing that Sony has never seemed to get right.

    Anyway any info about auto-focus will be useful.
    Thanks
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    John
    Sony fanboy, shamelessly shilling for "the man" since 2010.

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    Re: A7R II Auto Focus Evaluation

    I was lucky enough to pick up a A7rII today. First thing I did once I had charged the battery is throw on the metabones adapter and try out my 135L. The camera will not focus, period. It just searches over and over. I think all the hype regarding autofocus with non-native lenes was a bit off. After some more testing it seems the camera will NOT focus with any focal length over 100mm.... and if it happens to find focus it takes forever which makes it pretty much unusable. However at any focal length of 100mm and below it seems to autofocus as fast my 5d mkII. I cancelled the preorder I had placed on a 5DsR to take a chance with the Sony. I am debating returning it for the Canon if autofocus will continue to be unreliable. I really like everything Sony has been doing and LOVE my A7s, but really wanted something with which I could use my Canon glass. Not sure what move I'll make yet.

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by sideeffects View Post
    I was lucky enough to pick up a A7rII today. First thing I did once I had charged the battery is throw on the metabones adapter and try out my 135L. The camera will not focus, period. It just searches over and over. I think all the hype regarding autofocus with non-native lenes was a bit off. After some more testing it seems the camera will NOT focus with any focal length over 100mm.... and if it happens to find focus it takes forever which makes it pretty much unusable. However at any focal length of 100mm and below it seems to autofocus as fast my 5d mkII. I cancelled the preorder I had placed on a 5DsR to take a chance with the Sony. I am debating returning it for the Canon if autofocus will continue to be unreliable. I really like everything Sony has been doing and LOVE my A7s, but really wanted something with which I could use my Canon glass. Not sure what move I'll make yet.
    Check out this video (in German) which compares AF with various Canon lenses: https://vimeo.com/135374765

    According to the video, AF speed greatly depends on whether you're using a newer or older lens. The 135L is a great lens but it's definitely an older design (1996). In the video he tries the 100L and its AF looks pretty good. But when he compares the old 70-200/2.8L with the new 70-200/2.8L version II the difference in AF speed is dramatic. The old one basically can't AF, while the new seems to do OK.

    Similarly, according to this video -- https://www.youtube.com/watch?t=1270&v=J__afw25NBE -- at about 20:40, Canon lenses post-2006 will AF better than Canon lenses pre-2006.
    Last edited by Zlatko Batistich; 5th August 2015 at 23:49.

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by Zlatko Batistich View Post
    Check out this video (in German) which compares AF with various Canon lenses: https://vimeo.com/135374765

    According to the video, AF speed greatly depends on whether you're using a newer or older lens. The 135L is a great lens but it's definitely an older design (1996). In the video he tries the 100L and its AF looks pretty good. But when he compares the old 70-200/2.8L with the new 70-200/2.8L version II the difference in AF speed is dramatic. The old one basically can't AF, while the new seems to do OK.

    Similarly, according to this video -- https://www.youtube.com/watch?t=1270&v=J__afw25NBE -- at about 20:40, Canon lenses post-2006 will AF better than Canon lenses pre-2006.
    Thanks for the links. AF on the A7R II with 3rd party lenses is a deal maker/breaker for me.

    bwa
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    Re: A7R II Auto Focus Evaluation

    Since we just found out you need canon lenses made after 2006 to operate as they are in those videos. I have a very long bitch comment to make about these folks not warning the buying public till now. Seriously don't get me started I will have to ban myself that's how mad I am.

    Why I constantly say be careful of what your reading and from whom.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com
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    Re: A7R II Auto Focus Evaluation

    I received the A7rII this morning, and since then have been doing the usual battery of tests. Yes, the DR with this camera is considerably better, smoother than my A7II. I'll try and post some images tomorrow.

    re: AF - I just spent an hour on the couch as it grew dark outside. On my lap was the A7II, A7rII, and the FE50mm lens. I periodically tried to spot focus on a small object in the corner of the darkening room.

    Result - When the A7II started to hunt, hunt, hunt and then inaccurately claim it found focus, the A7rII was much faster and totally accurate.

    This needs more experimenting, but at first blush I'd say the A7rII will find focus in darker situations and do so with improved accuracy.
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    Re: A7R II Auto Focus Evaluation

    Metabones IV

    Canon EF 85 1.8--hunts without finding focus, unusable in AF.

    Canon EF 50 1.2L -- focuses quickly and well.

    Canon 40 2.8 STM-- also focuses quickly and well, maybe just a tad slower than 50 1.2

    Voigtlander 35 1.2 v2 with Voigtlander adapter works well (no surprise, it worked superbly on the A7r)

    Rest of the Leica M mounts will have to wait a few days until I can take a close look.

    I'm really leaning towards some lenses that won't require adapters.

    When I owned the A7r I owned the 35 2.8 and 55 1.8 which has all since been sold. It took 3 copies before I got an acceptable 35, first time I've ever gone through that and I will not go through that again... The 55 1.8 always worked well, was wildly sharp except I never really warmed to the draw of that lens.

    Probably going to do a few rentals at LensRental to find the ones I like.
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    Re: A7R II Auto Focus Evaluation

    Thanks for the info. Good luck with your lens hunting!
    I'll be curious what you decide to keep in the end.

    As AF FE lenses I have currently the 35/2.8 and 55/1.8.
    Next I'll get the Batis 25/2.
    I seem to prefer prime lenses as they seem more flare resistant on my A7R, NEX-5N, and NEX-7.
    Unfortunately I have to wait a few weeks before Amazon gets around to ship my A7RII. Oh well.
    With best regards, K-H.

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by dandrewk View Post
    I received the A7rII this morning, and since then have been doing the usual battery of tests. Yes, the DR with this camera is considerably better, smoother than my A7II. I'll try and post some images tomorrow.

    re: AF - I just spent an hour on the couch as it grew dark outside. On my lap was the A7II, A7rII, and the FE50mm lens. I periodically tried to spot focus on a small object in the corner of the darkening room.

    Result - When the A7II started to hunt, hunt, hunt and then inaccurately claim it found focus, the A7rII was much faster and totally accurate.

    This needs more experimenting, but at first blush I'd say the A7rII will find focus in darker situations and do so with improved accuracy.
    Andrew:
    Thanks much for your comment. That's exactly the answer I was looking for. When you've had a chance to shoot outdoors in daylight and reviewed your shots on the computer, I'd be interested in knowing what the percentage of shots in really good focus was. It would be a nice situation to know that Sony was past the point of needing to improve daylight focus on static subjects. Thanks
    Regards,
    John
    Sony fanboy, shamelessly shilling for "the man" since 2010.

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    Re: A7R II Auto Focus Evaluation

    So far it would appear that it is maybe a little better than the A7II but for me it is early days. What I do notice though is how much better and quicker my Leica Q is at locking onto a subject which is somewhat disapointing though of course I have still to get me head around some of the Sony's new focussing modes

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by Viramati View Post
    So far it would appear that it is maybe a little better than the A7II but for me it is early days. What I do notice though is how much better and quicker my Leica Q is at locking onto a subject which is somewhat disapointing though of course I have still to get me head around some of the Sony's new focussing modes
    David:
    I have not shot with either the A7II or the A7rII. As a point of reference, with either one of those two cameras, would you say if you were outside on a sunny day with the sun behind you and focused on static objects like a tree or a building would the likelihood of the photos being perfectly focused on the point you picked be greater than 90% (9 out of ten keepers)? With the A7r or the A7S I'd say the chance was much less than 90%.
    Regards,
    John
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    Re: A7R II Auto Focus Evaluation

    After a few days, I cannot recall ever getting a single "false positive" AF with the new camera. It's still early to be definitive.

    Side note - it's lock on tracking is superb. I spent some time yesterday in a dog park, where the action is non-stop. I used the smallest flexible spot, locked on to the dog-of-choice, and the AF successfully followed it around amongst all the crowd and chaos.
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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by jfirneno View Post
    David:
    I have not shot with either the A7II or the A7rII. As a point of reference, with either one of those two cameras, would you say if you were outside on a sunny day with the sun behind you and focused on static objects like a tree or a building would the likelihood of the photos being perfectly focused on the point you picked be greater than 90% (9 out of ten keepers)? With the A7r or the A7S I'd say the chance was much less than 90%.
    It is really to early to say as I have only had the camera a day and half and am having to get to grips with it's quite complicated focus system.
    As an aside I would say that when i use my A7s I probably get at least a 95% success rate when using flexible spot with contemplated subjects

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by dandrewk View Post
    After a few days, I cannot recall ever getting a single "false positive" AF with the new camera. It's still early to be definitive.

    Side note - it's lock on tracking is superb. I spent some time yesterday in a dog park, where the action is non-stop. I used the smallest flexible spot, locked on to the dog-of-choice, and the AF successfully followed it around amongst all the crowd and chaos.
    Wow, that's really encouraging. If it would do that with Canon glass (caveat post-2006 noted) then it would be absolutely fabulous for wildlife applications too.
    Too much to list, let's just say I have a bad case of GAS.........

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by dandrewk View Post
    After a few days, I cannot recall ever getting a single "false positive" AF with the new camera. It's still early to be definitive.

    Side note - it's lock on tracking is superb. I spent some time yesterday in a dog park, where the action is non-stop. I used the smallest flexible spot, locked on to the dog-of-choice, and the AF successfully followed it around amongst all the crowd and chaos.

    Andrew:

    You're right. It is still early. But what you say sounds extremely encouraging. I'm not a sports shooter. All I need is accurate normal AF. If Sony has got that under control then I've reached the "Promised Land."
    Regards,
    John
    Sony fanboy, shamelessly shilling for "the man" since 2010.

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    Re: A7R II Auto Focus Evaluation

    My 10 cents:

    The single shot non continuous AF on the A7R and A7s seemed fine to me and, provided one understood what kinds of target were too ambiguous, success rates were as close to 100% as I'd expect. The A7RII to me seems as good but notably faster, but still just as easy to fool with ambiguity, as are pretty much all cameras I've used. But it still isn't quite as fast as my D810.

    The advantage though is that when using Contrast Detect only (the only way I have yet used it) there's no need to AF fine tune your lenses - something I have spent many miserable hours doing with the Nikon - and try that with a zoom that needs different corrections for different ends of the zoom range, or for a lens with focus shift and/or field curvature...

    Next up: tracking. I rarely use it but sometimes I want to. The earlier A7 bodies were not great at this so I used my D810. The A7RII seems to me in about the same ballpark as the D810 - i.e. pretty useful but not stellar. Here's an example of my dog (I blurred the name tag, that's not a file problem!).

    I shot this in Manual mode with the 70-200 F4 zoom and with shutter speed set to 500 and F8, Auto ISO and -1/3rd stop compensation.

    I used continuous focus but single shot mode, and the expandable flexible spot with Lock On. It works really pretty well though for me the acid test will be BIF and I'll give that a go next week.

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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by tashley View Post
    My 10 cents:

    The single shot non continuous AF on the A7R and A7s seemed fine to me and, provided one understood what kinds of target were too ambiguous, success rates were as close to 100% as I'd expect. The A7RII to me seems as good but notably faster, but still just as easy to fool with ambiguity, as are pretty much all cameras I've used. But it still isn't quite as fast as my D810.

    The advantage though is that when using Contrast Detect only (the only way I have yet used it) there's no need to AF fine tune your lenses - something I have spent many miserable hours doing with the Nikon - and try that with a zoom that needs different corrections for different ends of the zoom range, or for a lens with focus shift and/or field curvature...

    Next up: tracking. I rarely use it but sometimes I want to. The earlier A7 bodies were not great at this so I used my D810. The A7RII seems to me in about the same ballpark as the D810 - i.e. pretty useful but not stellar. Here's an example of my dog (I blurred the name tag, that's not a file problem!).

    I shot this in Manual mode with the 70-200 F4 zoom and with shutter speed set to 500 and F8, Auto ISO and -1/3rd stop compensation.

    I used continuous focus but single shot mode, and the expandable flexible spot with Lock On. It works really pretty well though for me the acid test will be BIF and I'll give that a go next week.

    Tim:

    Thanks for your info. Can you expand on what you mean by ambiguous targets? I'm comparing the AF from my Sony A850 DSLR. I found it less likely to be confused than the A7R or the A7S. Possibly it has more to do with my skills at providing a target for the AF. Any tips for avoiding missed focus are very welcome.
    Regards,
    John
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    Subscriber Member tashley's Avatar
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    Re: A7R II Auto Focus Evaluation

    Sure John,

    A target can be ambiguous for many reasons and it depends on the AF system in use. For example, a Phase Detect system can get freaked out by repeated patterns. But what I mainly mean for the A7 series, being (with the exception of some models with some lenses and adaptors) Contrast Detect, is the sort of ambiguity presented by the camera not knowing exactly what within the frame you want it to focus on. For example, the first two shots below might be marginal to a sloppy shooter but the second two are just too ambiguous to reasonably expect the camera to make a decision on:









    In fact the camera didn't get it 'right' in either of the last frames, because it didn't 'know' that I wanted to focus on the wire. In one it missed entirely, and in the other it almost got it but favoured the grass in the foreground slightly.

    The camera isn't psychic, it can't know what we are thinking but luckily we are psychic, because in general we can know what it is thinking. Which is:

    * I am going to look within and slightly around the focus spot my user has chosen
    * Within that spot, I am going to find a line of contrast between two adjacent areas and I am going to jiggle focus back and forth until that line is most contrasty.

    That's a bit reductive but it's about right. So if you hover the focus spot over an area with no contrast, or where the contrast is a line between two subjects at different distances, it'll quite likely get confused. It can also get confused if there's a stronger line of contrast just outside the spot you chose - especially if you use the expandable spot option.

    Provided you can give the camera what it needs it will pretty much never get it wrong in my experience (unless the light is very low). But you can't always do that. So may I suggest the following: set the camera to MF and then set the AF/MF AEL switch to AF/MF. Then to focus automatically, quickly press and release the button in the centre of that switch (if the target meets the camera's requirements) with your thumb whilst keeping your index finger on the shutter button. If you are in doubt, a quick twist of the focus ring will give you magnified manual focus to fine tune. It works.

    One other thing: CD systems are better with fast lenses and longer focal lengths because they get more light (and therefore more contrast) and they get less DOF and therefore more discernible contrast shifts. It might be harder to focus longer faster lenses because it requires more accuracy, you might not always see the benefits of this, but if you are using a long fast lens the camera will 'see' the contrast better. The only thing I haven't yet bottomed out is how the camera interacts with apertures in terms of whether it is stopping down to focus. Some Sony cameras have done this, depending on the aperture range you're shooting in, but I can't remember the somewhat complex algorithm that governed the behaviour. I wrote it up somewhere once. It's a difficult decision as to whether you want it to or not because on the one hand stop down focussing automatically eradicates the effects of focus shift but on the other hand it gives the camera less light and contrast to work with.

    Edit; i just checked the 70-200 F4 I currently have mounted and it opens the aperture to wide open when focussing. That may not be the same for all the system lenses: if Sony know that a particular lens has focus shift then it might stop down to focus with that particular lens, I don't know without checking them all but the RX-1 used to do this at some apertures.
    Last edited by tashley; 9th August 2015 at 11:59.
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    Re: A7R II Auto Focus Evaluation

    Quote Originally Posted by tashley View Post
    Sure John,

    A target can be ambiguous for many reasons and it depends on the AF system in use. For example, a Phase Detect system can get freaked out by repeated patterns. But what I mainly mean for the A7 series, being (with the exception of some models with some lenses and adaptors) Contrast Detect, is the sort of ambiguity presented by the camera not knowing exactly what within the frame you want it to focus on. For example, the first two shots below might be marginal to a sloppy shooter but the second two are just too ambiguous to reasonably expect the camera to make a decision on:

    In fact the camera didn't get it 'right' in either of the last frames, because it didn't 'know' that I wanted to focus on the wire. In one it missed entirely, and in the other it almost got it but favoured the grass in the foreground slightly.

    The camera isn't psychic, it can't know what we are thinking but luckily we are psychic, because in general we can know what it is thinking. Which is:

    * I am going to look within and slightly around the focus spot my user has chosen
    * Within that spot, I am going to find a line of contrast between two adjacent areas and I am going to jiggle focus back and forth until that line is most contrasty.

    That's a bit reductive but it's about right. So if you hover the focus spot over an area with no contrast, or where the contrast is a line between two subjects at different distances, it'll quite likely get confused. It can also get confused if there's a stronger line of contrast just outside the spot you chose - especially if you use the expandable spot option.

    Provided you can give the camera what it needs it will pretty much never get it wrong in my experience (unless the light is very low). But you can't always do that. So may I suggest the following: set the camera to MF and then set the AF/MF AEL switch to AF/MF. Then to focus automatically, quickly press and release the button in the centre of that switch (if the target meets the camera's requirements) with your thumb whilst keeping your index finger on the shutter button. If you are in doubt, a quick twist of the focus ring will give you magnified manual focus to fine tune. It works.

    One other thing: CD systems are better with fast lenses and longer focal lengths because they get more light (and therefore more contrast) and they get less DOF and therefore more discernible contrast shifts. It might be harder to focus longer faster lenses because it requires more accuracy, you might not always see the benefits of this, but if you are using a long fast lens the camera will 'see' the contrast better. The only thing I haven't yet bottomed out is how the camera interacts with apertures in terms of whether it is stopping down to focus. Some Sony cameras have done this, depending on the aperture range you're shooting in, but I can't remember the somewhat complex algorithm that governed the behaviour. I wrote it up somewhere once. It's a difficult decision as to whether you want it to or not because on the one hand stop down focussing automatically eradicates the effects of focus shift but on the other hand it gives the camera less light and contrast to work with.

    Edit; i just checked the 70-200 F4 I currently have mounted and it opens the aperture to wide open when focussing. That may not be the same for all the system lenses: if Sony know that a particular lens has focus shift then it might stop down to focus with that particular lens, I don't know without checking them all but the RX-1 used to do this at some apertures.
    Hello Tim:

    Thanks for that very clear and well laid out explanation of the auto focus conditions for the A7 cameras. I guess the wedding shooters are going to have to have good OSPDAF instead of just CD when they need the shot to count. Definitely no time for the manual focus magnified check. Even though I've briefly used the A7 most of my experience has been with CD only A7 cameras (A7R and A7S). And from what I've heard the OSPDAF on the A7 II and the A7R II have a much more powerful algorithm for hybrid focusing. Anyway thanks for your info. It is appreciated. I'm going to have to rent this camera to see for myself what it feels like.
    Regards,
    John
    Sony fanboy, shamelessly shilling for "the man" since 2010.

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    Re: A7R II Auto Focus Evaluation

    So yesterday I viewed this review...


    https://www.youtube.com/watch?v=XxxKAJtBnhA

    and it had some very clear statements about autofocus:
    1) In good light the autofocus was excellent.
    2) In low light without the red AF assist light it was not good.
    3) With Canon lenses it was very good (in good light).

    My way of interpreting this is that Sony has cracked the first barrier. They have achieved AF comparable to Canikon in daylight conditions. They still need to produce excellent autofocus in low light to be able to win over the wedding togs and the indoor and night sports shooters.

    At this point I am convinced that Sony is going to overtake Canikon. I don't currently need the A7R II (currently using an A7S) but I feel confident that the next Sony I buy (A7, A9) will be a camera that can successfully autofocus at a soccer game or barbecue. And someday they'll have one that autofocuses at a wedding hall. I'm now officially a Sony fanboy (is that a Sanboy?).
    Regards,
    John
    Sony fanboy, shamelessly shilling for "the man" since 2010.
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