Q&A with Sony’s Mark Weir: Will full-frame go mirrorless, and what’s the deal with Dual AF?

by Dave Etchells

posted Friday, September 21, 2012 at 1:29 AM EDT

Mark Weir, Senior Manager of Technology and Marketing at Sony Electronics Inc.

Imaging Resource Founder and Publisher Dave Etchells talked with Mark Weir, Senior Manager of Technology and Marketing for Sony Electronics Inc., at Photokina 2012. Weir discussed the attention-grabbing RX1 full-frame compact camera, as well as the unique Dual AF system of the Sony Alpha A99, and that camera's renewed focus on video capture. He also offered insight into some of the unique features in the company's NEX-series mirrorless cameras and how they've been received in the market, and discussed the future of WiFi in both consumer and professional photography.

Dave Etchells/Imaging Resource: This has definitely been a groundbreaking series of product announcements for Sony. The Alpha A99 is certainly poised to shake up the industry a little, the RX1 is really catching the imaginations of the street photographers, and the NEX-6 looks like a really interesting model for those stepping over from an SLR. Is this just a particular confluence of announcements timed for Photokina or is it indicative of the longer term ramping up of Sony’s R&D efforts in imaging?

Mark Weir/Sony: I think we can say that camera development follows device development. And certainly, we’ve been hard at work creating the key devices from which we make new cameras particularly in the area of full-frame sensors and then the processors that handle the data from the sensors, particularly the autofocus data and also the 14-bit raw data that’s coming from our new full-frame image sensors. So I think you could say that as the devices are developed, the cameras follow thereafter. I don’t think that it was really developed for any particular trade show, but certainly now that those devices have been developed, we’re moving ahead as quickly as possible with cameras that use them.

DE: There has been a lot of confusion about the function of the two sets of phase-detect AF sensors on the A99. Now that you’ve had a little more time with the product, can you explain in more detail how they work together? Does one set provide coarse data while the other is used for fine adjustments? What’s the benefit of having two separate sets of phase-detect sensors?

MW: Well, with the focal plane phase detect 102-point array and the 19-point conventional sensor, what we’re able to do is enable two features. One is AFD which is Autofocus with a Depth map, and also AF range.

AFD, which is the primary function, allows the additional points to provide a depth map of information from which the camera can operate. Not only is the coverage area expanded but the density of the points is expanded as well. As a result, subjects that are moving rapidly or subjects that are moving erratically not only have a wider area of coverage, but there is also a greater likelihood that as they move through the frame, they’re always going to have at least one if not several AF points that they’ll be passing through to allow the camera to have not only much more accurate, but much more consistent focus data to work from. So this is particularly important in the context of very small subjects that might be moving across a complex background that might cause lesser AF systems to become distracted off of the target and on to the background.

It’s also the case if there are subjects moving in the foreground that might distract the AF system as well. So particularly for subjects that are moving rapidly or erratically, particularly useful in sports, and also for users that are shooting for instance birds in flight with high-magnification telephoto lenses. This is also important as well. Not only is it that the area is expanded, but also the density of the AF points is expanded as well, so that it’s much more likely that the subject is going to be covered by an AF point as it moves through the frame. So that’s AFD. That’s a very important development and we think it’s really going to aid consumers who are shooting difficult-to-track targets.


Another area is AF range control, and this is helped not only by the 102 AF point array but also by the conventional sensor. It doesn’t really require one or the other, but range setting is facilitated by the focal plane phase-detect sensors. And what this allows you to do is to declare an area that the AF system will ignore when shooting both in the foreground and the background, and this is particularly useful when you’re forced to shoot through something in the foreground, like a net or a fence, something that you don’t want the AF system to be distracted by. It also helps again with complex backgrounds and subjects moving across a complex background where the AF system could easily be distracted. So that’s a particularly useful function.

And then a third function, which really isn’t for stills, but for video: the ability to control the AF duration time. You can set it to three different settings, which really regulates the way the AF system reacts to motion as the subject moves across the plane.

But all of these modes to a greater or lesser extent are based on the idea of having two different phase-detect AF sensors. A conventional AF sensor as we know it in SLRs so far really concentrates on camera to subject distance, whereas the focal plane phase-detect sensors really are concentrating more on how the subject is moving across the image plane. And by having both sets of data available to the focusing system, there’s much more information from which the AF system can make the correct decision, not only on focus accuracy but primarily on focus consistency, the ability to not be distracted by objects that might be in the frame that are not the subject that you’re trying to shoot.

DE: I hadn’t thought about it from that standpoint before. But rather than thinking of the image plane phase-detect sensors is being autofocus points, it’s more like thinking of that becoming a depth sensor. So the camera actually has a depth map of the frame that it can use to figure out where the subject is and how it’s moving.

MW: Yeah. I think it’s really not so much about speed or even accuracy, but rather consistency and repeatability. There are plenty of very, very accurate and very fast AF systems in the world today. But whether they can avoid being distracted by other complex elements that are in the scene is one of the great challenges of focusing systems. So with this added information as well as the density of information, what we can do is we can improve the predictability of the AF system, and also the predictability of AF tracking because there’s so much more information to work with.

DE: Is there any difference in accuracy between the in-plane phase detect and the separate phase-detect system?

MW: Not really. Again, it’s been suggested by some that since the focal plane phase detect is at the image sensor plane itself, it should have an effect on back focus or front focus, but not that we’ve been able to see.

DE: When I was thinking of accuracy, I wasn’t so much thinking of back or front focus as whether there’s a difference in its ability to discriminate focus. Does either one of them have a finer gradation of discrimination than the other.

MW: I don’t think so.

DE: It occurs to me that one limitation of the in-plane phase-detect could be the very small pixels. I think typically AF sensors that are separate sensors have larger pixels so therefore maybe they’re more sensitive to light, are there differences in light sensitivity between the two systems.

MW: We haven’t published a specification for [sensitivity of the AF points]. But we believe that the primary issue is taking advantage of the closer spacing that is available when you’re using focal plane phase-detection. Again, you can significantly increase the density of AF points and therefore improve the reliability of the focus in real life. These systems do not operate independently of each other. There is no method by which you can select the main AF sensor or select the focal plane AF sensor instead and choose the one that you want to work with. They work together as a system.

DE: And I suppose conventional AF sensors only work with a small fraction of light coming from the subject anyway because it always goes through partially silvered mirror. That perhaps argues back in favor of the focal plane AF having good sensitivity.

Related to that is the question of whether there is a difference in minimum aperture that the sensors can work at with the typical external AF sensor, the base line spacing determines the minimum aperture it can work at with multiple points integrated across the array. Is that constraint relaxed any? Can the in-plane array utilize slower lenses?

MW: We don’t have any information on the base lengths of each of the sensors, so we haven’t yet been able to translate that into a minimum working aperture. We do know that the main AF sensor--as most sensors—is operating off of a 5.6 minimum. But as to what the minimum aperture is for the focal plane sensors or whether that translates in the same way as with a conventional AF sensor is still yet to be determined.

DE: Moving along, the A99 appears to be aimed at least in part at pro videographers who may find that its live phase detect autofocus is a real plus when filming action. Its data rates and memory card are well below those of the Canon 5D Mark III though. Is this an impediment or is the dominant use case really recording to an external recorder?

MW: Well, I think that data rate is really rather dependent upon the compression/decompression scheme that’s being used. In this camera, we have MP4 for 30P capture rates, and then we’re employing AVCHD and AVCHD 2.0. The maximum data rate for AVCHD 2.0 as implemented in this camera is 28 megabits per second. I wouldn’t say that a higher data rate than that is necessarily a better or worse picture quality, it’s rather evidence of a different codec. For instance, 50 megabit per second if you’re shooting 1,920 x 1,080 24P, it isn’t really the same thing. It’s just the variance and the compression and decompression scheme. However, with A99, we’ve essentially left that up to the user because with an uncompressed HDMI output, recording to an external device is a simple matter, and we’ve been able to record in excess of 100 megabits per second out of the uncompressed HDMI output.

DE: Do you know whether the A99 streaming HDMI output is 8-bit or 10-bit.

MW: We don’t have a specification for it, but I think there’s evidence to suggest it’s 8-bit.

DE: You mentioned the focus range feature of the A99 AF system. That’s a great innovation. I can’t tell you how many times I’ve been frustrated trying to shoot through a chain link fence. Is the focus range feature also available when recording video?

MW: I don’t believe so, but instead, we have a different feature for shooting video which is AF duration control. And that works remarkable well. We have sample video clips where someone’s shooting a subject in video and someone actually walks in front across the scene right in front of the camera, and it works remarkably well. It maintains AF on the subject because what you’re doing is you’re increasing the duration of the persistence.

DE: Shutter speeds for video recording go as low as a quarter of a second, is that correct? And what does the camera do, does it just record multiple identical frames until a fresh frame is exposed?

MW: It is correct, and it has actually been the case since the introduction of A77 and A65, and it’s also on NEX as well. I believe what it’s doing is it’s just leaving the shutter open. But in theory, it seems difficult to quite grasp. But yes, shutter speed can go lower than the frame rate.


DE: The NEX-6 is a pretty interesting product as well. Personally, I fell in love with the Tri-Navi interface on the NEX-7, but the NEX-6 moves away from that ostensibly to appeal to traditional SLR users. Is the Tri-Navi really that hard to sell?

MW: Well, I don’t think it’s a question of difficult to sell. Actually, there are many that really favor the NEX-7 because of its control interface. What we’ve done with NEX-6 is we’ve evolved it a little bit, and we’ve also focused on providing a physical shooting mode dial, which has been a request that we’ve received even with cameras like the NEX-7.

With a physical rather than a virtual shooting mode dial, obviously you have the control experience of the conventional digital SLR, and we wanted to maintain dual control wheels to have direct access. We also evolved the function key. Instead of having to press it repeatedly, you can press it to call up the function menu and then navigate across up to six setting items that you can program in.

Tri-Navi on the NEX-7 remains a great way to have direct access to numerous controls while shooting. It’s just that in the NEX-6, we prioritize the availability of a physical shooting mode dial.

DE: We got some reader questions about touch screens. We’re just excited to get the viewfinder on the NEX-6, but some people have an interest in seeing a touch screen as well. How did Sony decide where touch screens make the most sense?

MW: Well, I think it really is dependent upon the product concept. In the context of NEX-5 series models, we felt that touchscreen would be most appropriate there because we believe it fits the user style of the target customer for NEX-5. In the context of NEX-6, we felt that physical tactile control with hard knobs and keys were really more to the liking of that target user, and this is the reason why we put the touch screen in the 5 series, but put physical and mechanical controls in the 6 series. It’s really a question of the target user and the design of the product catering to the intended user in that way.

DE: So the answer is if you like touch screens, buy an NEX-5R.

MW: Yes. The design intention assumes that the target user for NEX-6 is more looking for the physical dials and controls rather than touchscreen. And if you think about it, it makes sense. If you’re using touchscreen control, you’re probably not using the eye-level shooting style that is really the primary role of cameras like NEX-6 and 7 because you really have to take the camera away from your face to operate a touchscreen, whereas while you’re holding the camera up to your face looking through the eye-level viewfinder, you’re really looking for a mechanical control that you can operate by feel, whereas a touch screen really requires a visual confirmation that you’re looking at the screen and you’re touching it as well. So it doesn’t really fit into the eye-level shooting style, which is really the priority of the NEX-6 and 7.

DE: Sony’s implementation of apps on their cameras is both intriguing and a little confusing. Are they perhaps best thought of as ways to incrementally extend the camera’s firmware rather than apps in a conventional sense?

MW: Well, we believe that the ability to increase the functionality of the camera is something that we should do, but at the same time, there is evidence to suggest that cameras have become so feature and function-rich that in many cases there are features and functions that customers not only don’t use but aren’t even aware of. So we believe that while functions and features expand continuously, we also think that there’s room for customization. That is that customers should be able to add those features and functions that they feel are necessary or they would value, and then skip out on others. So I believe that with the concept of camera apps, that ability to customize to your application really makes more sense.

Many of the apps that we’re offering are free. So the notion that these should be included anyway, which is something that some have expressed--perhaps that’s true--but at the same time, customers now have the freedom to add or not add functions as they see fit, and we think that’s a real advantage.

DE: That’s interesting. I hadn’t thought of them in that light. So it’s a way of expanding camera capability without burdening every user with all that added functionality.

MW: Correct. Because some may look at some of the functionality and say, “Well gee, it doesn’t really appeal to me. Why would I have that in my camera?” And now, the user can make that decision for themselves.

DE: Are there any plans to offer an API at some point that would let others develop apps for Sony cameras?

MW: At this time, our plan for camera apps are those that are developed by Sony. We see the camera as being a somewhat different device than a smartphone or a tablet, and the ability to maintain the performance and reliability of a camera in the context of the device that it is really puts us in a position where the apps that we’re going to offer are those developed by Sony.

DE: With an apps interface present, even if it’s closed to the outside world, maybe there is a potential for something like the CHDK that exists for Canon PowerShots; a hacker’s kit.

MW: We try never to underestimate the ingenuity of the user community.


DE: Question from one of our editors: The Sony RX1 is probably the most startling announcement of the show. We’re curious how long the gestation period was. Was this a product that has been on the drawing board for a long time or something that came together rapidly once the technology made it possible?

MW: Honestly, I’m not aware of the development schedule for products like this. But all you really have to do is to take a look inside the product. We have disassembled display versions here at Photokina, and I think you can see that there are several key devices in the camera that probably took quite a while to develop; not only the image sensor but also the unique lens that is featured in the RX1 was no small feat of development. But in terms of the exact development time schedule, I’m not aware of that.

DE: Yes, the lens really is amazing. They showed me a sample before I came here: that cutaway, it’s just unbelievable. The enormous rear element and the fact that it projects so far into the camera body, it’s definitely a different approach.

MW: Yes, the RX1 is a purpose-built, non-interchangeable lens camera. The idea of not being able to exchange the lens has caused some wonder on the part of some observers. But I think the camera itself represents what can be done if the design intentionally does not incorporate lens interchangeability, and the result speaks for itself.

RX1 is by far and away the world’s smallest and lightest full-frame camera. And much of that is simply because the lens was designed from the ground up without the idea of interchangeability. It’s quite a bit more compact than any comparable lens, and it incorporates design elements that you would never--or at least I think you can say you would almost never--have in an interchangeable lens, particularly the idea of putting the shutter in the lens instead of a focal plane shutter in front of the image sensor.

DE: Of course, medium-format cameras for years now have had shutters in the lenses.

MW: Right. That’s why I said ‘almost none.’

DE: I’m wondering though. Is there really anything about that design that would preclude an interchangeable lens because certainly, the back focus distance is very small and the lens projects pretty far into the camera body, but it seems like where you put the flange doesn’t really matter that much, does it?

MW: Well, I don’t think it’s really the issue of the flange, although the flange does take up some space of its own. But I think that in the context of a mount system, it’s somewhat impractical to develop a mount system that presumes that there will be a shutter in every lens and there will be no focal plane shutter. I think the real issue is whether or not there is a focal plane shutter, because if there is, then there is a certain degree of flange back distance that’s almost automatic.

DE: I guess it’s a little problematic, the idea of having lenses with all this glass and delicate optics hanging out the back, exposed.

MW: Sure. All you have to do is to take a look at a disassembled model of the RX1 and it becomes quite clear, some of the advantages that you have when you avoid lens interchangeability and how those advantages are realized in the product. One thing is for sure, no worries about dust on the image sensor with a non-interchangeable lens camera.

DE: Is the RX1’s sensor the same as the one in the A99? And if so, why is there no phase detect AF on the RX1?

MW: Well, the sensor is basically the same design, the same structure, the same generation of development, the same advantages in terms of sensitivity and dynamic range, it offers the 14-bit output. However, in the RX1, a variant of the sensor without phase-detection pixels was selected because the plan for the camera was for it to be contrast-AF from the beginning.


DE: Does a full frame mirrorless interchangeable lens camera make sense?

MW: Well actually, we just introduced one. It’s called the NEX-VG900. Most think of it in the context of a camcorder, but it is also an admirable still camera as well, and it does have an E-mount and it does have a full-frame image sensor, and you can use E-mount lenses on it. Needless to say with an APS-C crop, or it’s also supplied with the LA-EA3 mount adapter, so it also offers an A-mount as well. But the idea of a full frame E-mount camera, yeah, we already announced it, it’s called the NEX-VG900.

DE: Well, obviously very different form factors. I guess the question is does a rangefinder-style full-frame interchangeable lens mirrorless makes sense?

MW: Well, I think everyone understands that if we can make the VG900, we could make a still camera variant of that. But what’s really on everyone’s mind, I would imagine, is an E-mount interchangeable lens camera together with E-mount full frame interchangeable lenses, and that’s a different discussion. But can the camera be made and can it use full frame A-mount lenses? Yes, the product in the context of the VG900 was already announced. We have them on display here. But I think what those who are suggesting that a full-frame E-mount camera be developed is a full frame E-mount camera together with E-mount lenses that would operate with it and offer full frame coverage. And all one has to do is to look at the RX1 disassembled model and see the optical challenge that would represent.

DE: I’ve seen reference to a fixed-lens group within Sony associated with the RX1. Does the RX1 come from a different lineage within the company than the Alphas?

MW: Well, the RX1 is a Cyber-shot, and it was developed by the Cyber-shot group. Needless to say, there is plenty of interchange of ideas and the technology within Sony’s different development groups. All one has to do is to take a look at the three different full-frame cameras that were announced here at Photokina--the NEX-VG900 camcorder, the DSC-RX1 Cyber-shot, and the SLT-A99V Alpha--and you can see that the groups are very cooperative and work with each other a lot.


DE: This a reader question. I’m not sure if it’s a fair one given that you’ve just come out with the RX1, but the reader asks: If you were to create an RX10, what would that look like?

MW: I have no idea how to answer that question because I don’t understand--I can’t quite grasp the relationship between 1 and 10, or 1 and 2 or 3. But it’s sufficient to say that when Sony provides the 1 in the model name, it’s usually a pretty significant development. I mean, going back in history, the last non-interchangeable lens camera that we created with the impact of the RX1 or near the impact of the RX1 would be the DSC-R1 which was introduced in 2005. So seven years separating those models. I think the RX1 is a pretty timeless design.

DE: There seems to be a big groundswell of Wi-Fi in cameras helping to counter the threat from socially connected smartphones and tablets. How do you see this continuing? Will all cameras one day be Wi-Fi capable?

MW: Well, I don’t know that all will be, but certainly the benefit to a camera with Wi-Fi connectivity is there because it really allows the camera to concentrate on being a camera, and a smartphone to concentrate on being the communicator for the camera. Obviously, much has been said and much has been written about the superiority of cameras over smartphones as image capture devices, and I think simply adding Wi-Fi adds that step of connectivity to the camera, which really clarifies the issue of the role of the device.

Obviously, we know that image capture with smartphones will continue apace. But certainly with a Wi-Fi equipped camera, consumers now have the choice to maintain connectivity, and at the same time enjoy the benefits of a device that’s really more centered around image capture than communication. But you know, time will tell how far that extends. Plenty of manufacturers have introduced Wi-Fi equipped cameras. We’ve even seen a Wi-Fi equipped DSLR. But where the customer demands the product, that will remain to be seen.

DE: Apart from Samsung, Sony is the only camera maker who is also a major cell phone manufacturer. Can we look forward to seeing an Android-based camera from Sony at some point?

MW: Well, we rarely--if ever--comment on what we plan to do in the future. But I think the customer is really the ultimate decider of the kinds of products that are developed. And if we look through the use case, I think we can see that it might be a challenge to create a product like that, because if the camera behaved exactly as a cell phone, then it would require a data plan. And whether the customer would buy another device besides their cell phone that required a monthly data plan, might be the deciding factor. You know, I think most consumers are burdened enough, shall we say, with the data plan for their phone asking them to carry another data plan every month for their camera might not be well-received.

DE: That’s an excellent point. That’s a huge cost factor for the consumer.

MW: Yeah. But it’s not about what the technology can do, it’s really about what the customers will embrace. And I think that this is one of those cases where the customer and what the customer is looking for really has to drive, in this case, whether or not the product is developed.

DE: Jumping back to the app issue for a little bit. It seems like everything has been “appified” these days. We have app stores on the phone, the computer, now the camera, what about more of a pro workflow like the A99? Could we expect to see innovative apps that would support pro workflows in different ways?

MW: Well, in the context of apps and customizability, we focused PlayMemories camera apps on the NEX E-mount cameras, because we do believe that there is a certain degree of fun and innovation and personality if you will, adding personality to photography. It really fits in well with the idea of the E-mount product lineup, and that’s really where we focused our apps in the NEX-6 and the NEX-5R.

Will they have a place in the conventional SLR? That remains to be seen. Will they have a place in the workflow? I think that remains to be seen as well. But in the context of a camera like A99, our focus has been to support the pro workflow of PC control instead of remote control, the idea that you can tether the camera to a PC and do all of the things that a studio shooter, for instance, would normally look for in terms of functionality. So that is built in the A99. That’s not really in the context of apps per se.

But the idea of customizability and personalization, that’s really something that we’ve focused on, the E-mount cameras for now.

DE: A number of pro cameras offer Wi-Fi adapters to facilitate uploading images from the field. Do you see similar Wi-Fi connectivity to smart devices in a pro level device?

MW: Honestly, I’m not really sure. If we consider the pro workflow, I don’t know that the cell phone is really the correct tool for communication for the pro workflow. If you look at 24 megapixel or greater resolutions particularly with the raw files that go with them that the pros will be shooting, it’s going to take a pretty solid data plan to be uploading the quantity of images that would be part of the pro workflow. Certainly possible, no doubt, and certainly right for some photographers. But if we look at 30+ megabyte raw files, particularly lots of them, that may or may not be the best way to transmit files of that size and quantity.

It could be done, sure. But whether that makes sense on a cellular network is--I’m not sure that the world is ready for that just yet.


DE: Sony recently announced its first action camera model stepping into a market that has grown pretty rapidly over the last couple of years, what spurred Sony’s decision to enter that market now?

MW: Well first of all, growth, customer interest. But I also think that it’s not being done particularly well now. It’s not being done with Sony technology, and we thought that we could add a significant amount of customer value and benefit with our action camera.

Three areas that really jump right out are the use of our image sensor--the Exmor image sensor--really allows low light capability that it’s very tough to match in terms of the products that are available today. We’ve added the Carl Zeiss optics, which can’t be matched in the product offerings that are available today, and also image stabilization. We think that’s a pretty important feature for this user, and we think it’s pretty important for this type of product. So just three basic features: low light sensitivity, image stabilization, and high quality optics, we think will do a lot for what is being captured by this user for the point-of-view camera application.

So we think that that’s very important. We’ve also done things with the method by which we integrate Wi-Fi. It’s not a separate module; it actually is the same size camera. We think that we’ve done a lot with miniaturization to make the product much smaller and take up less space and be less invasive. Because let’s face it, point-of-view cameras can get in the way if they’re too large depending upon the way they’re used. So we think that offering something very small, very compact, makes it a lot more useful.

But we think that the combination of what we bring to the category, the product that we created, we think would be very attractive in the market.

DE: So basically, the answer is that you thought you could do a better job.

MW: Well, let’s face it. We don’t want to be too presumptive, and the competitors in the space are already very well-regarded. But we felt that what we could offer would be a little bit different.

DE: Thanks as always for a remarkably informative interview, and for making the time for us at a busy show!

MW: My pleasure. Thanks, Dave.