Sony a1 Bird Eye AF – The Good and the Bad

The list of features in Sony’s flagship a1 are extensive, but one of the standouts for me is the addition of a dedicated bird eye autofocus system. Before the a1 came along, Sony’s most recent mirrorless cameras had an Eye AF mode that was switchable between human and animal. Real-time human eye tracking is and has been for some time, almost uncannily accurate. Real-time animal eye tracking is truly excellent with land mammals. Can the new Bird Eye AF mode live up to standards set by the existing eye-tracking modes?

I purchased my Sony a1 at a regular retail store. Although I got my hands on one of the first in Canada, there were still many journalists and Sony Artisans that had their hands on an a1 before me. Every time I saw a report posted, I would look for some information on the bird eye autofocus mode, keen to see whether it was going to live up to the existing high bar, and the hype during the a1 launch.

What I found was a mixed set of opinions. Tony Northrup published an initial video about the a1 where he said that bird eye AF was somewhat mediocre. But others, such as Sony Artisan Chris Dodds was saying it was truly excellent. Was this just a case of Sony sponsored shooters blowing smoke? In the end, I decided I was only going to be able to answer this question with some hands-on time.

Real-Time Eye AF for Birds – Impressions

All of the images on this page were shot with my own Sony a1, along with the excellent Sony 200-600mm f/5.6-6.3 G lens.

Real-Time Eye AF Subject Switching

In most situations I leave Eye AF turned on in my Sony cameras, then I switch the subject as needed. Even if there are no eyes in the photo, such as when photographing landscapes, autofocus still works just fine. With my a9 II camera, I only had to switch subjects between human and animal, which I usually did with a custom setting in the menu system.

With the a1, I quickly realized that this was no longer going to be the most efficient way to work. In a wildlife-rich environment, you might want to repeatedly switch quickly between animal and bird eye AF modes. To fix this problem, I assigned real-time eye AF subject to one of the custom buttons on the top of the camera, next to the shutter button. C1 or C2 will work fine for this. Now, with my eye to the viewfinder, I can quickly switch eye AF modes, cycling through human->animal->bird.

Living as I do in the Yukon, I like to keep a camera next to me when I’m driving anywhere. You never know what kind of wildlife is going to pop out in front of you. When it does appear, you might have only a few seconds to get a shot. Without having a custom button to switch eye AF subjects, you could easily find yourself in the wrong mode and wasting valuable time diving into the menus to fix it.

This is all less of a problem if you only shoot people. In which case you can leave the eye AF subject set to human. If you like to shoot wildlife, though, you will find yourself wanting to switch back and forth between animal and bird subject mode constantly. Honestly, I wish Sony had simply added birds to the real-time animal eye AF mode instead of giving it a separate mode. Let’s hope we don’t see more modes added in the future with increasingly granular subjects. Fish eye AF mode, anyone?

Does it Work?

Once I had the setup dialled in, I was very pleased to see excellent initial results with the bird eye tracking. While working on photos for my guide to backyard bird photography, I spent many hours in a photo blind in my yard, giving me ample time to draw some initial conclusions.

Honestly, after my first few hours working with it, I was blown away. Working with very small birds it would consistently pick out and lock onto an eye with just the same accuracy as I had seen when using the human or animal eye AF modes on my older a9 II. As birds would sit on a perch and turn their heads left to right, so the eye-tracking box would jump instantaneously to the opposite eye as it became visible. Sometimes it feels like cheating, it is that good.

Does Bird Size Affect Accuracy?

Having seen at least one of the Sony pros testing the bird eye AF mode on larger birds such as owls and eagles, I was curious whether the size of the bird would affect accuracy. Having now worked with the a1 for several months, I can categorically state that the size of the bird has absolutely zero effect on the AF accuracy. It remains just as accurate with small songbirds as it does with larger raptors.

But what about size within the frame? This was a surprise to me. I had expected to see far greater accuracy when a bird occupies a larger proportion of the frame. However, in practice, I saw no such results. I was constantly astonished to see the eye-tracking box appear on the eye of a tiny bird that occupied a tiny portion of the frame. The more I used it, the more comfortable I began to be with using a much larger autofocus area in the frame. Confident that the system would still pick out the eye.

Does Bird Eye Contrast Affect Accuracy?

My assumption before using this system was that it would be considerably more capable of picking out high contrast eyes. For example, I expected it to have little trouble finding a black eye on a white bird, but for it to have issues picking out a black eye on a dark bird. Again, I was wrong with my preconceptions here. I didn’t see any particular issues with darker birds, or birds with dark eyes within dark-feathered heads.

Does Bird Angle to Camera Affect Accuracy?

What about bird angle to the camera? The eye of a bird looks very different when the bird is facing the camera. Can the a1’s bird eye AF mode still pick it out and lock on? The short answer is yes. The slightly longer answer is that sometimes it takes a little longer, and jumps from one eye to the other when both are visible.

Small birds are usually twitchy, constantly moving their heads left to right. When a small bird is facing you, moving its head, you will see the tracking box jump from one eye to the other as the camera tries to decide which one to prioritize. In reality, this doesn’t really matter. Both eyes are roughly in the same plane of focus and it makes no difference which one it chooses.

Honestly, I was just impressed to see it working at all because the AI system must surely have a tougher job with this scenario. A bird can look distinctly un-bird-like when viewed from the front, instead of the side. Yet the system would repeatedly surprise me, and allow me to capture fabulous moments like the one above.

Does Bird Breed Affect Accuracy? – Uh Oh…

The title of the post did say I was going to tell you the good and the bad. So far it has all been good. Very good, in fact. But here we do get to the bad. When photographing the annual swan migration here in the Yukon, the bird eye AF completely failed. Every time.

I’m not saying it struggled, and sometimes missed focus. I’m saying that it completely, 100% failed to establish that a swan was a bird. It didn’t matter whether I was filling half the frame with the swan’s head, making the eye obvious and enormous, it simply did not recognize a swan as a bird. Instead of seeing the magic green eye-tracking box appear over the eye, it would think for a second and then default back to standard AF tracking modes.

This was disappointing. Clearly, the AI system that analyzes the subject within the frame, has been programmed with many different bird photos. But what Sony has done, is concentrate on more common regular bird shapes. The system seems to have no trouble with big raptors and small songbirds. Nor does it have any issue with a swimming duck that has its feet submerged. Thus proving that it doesn’t necessarily need to see the whole bird, to establish that it is, in fact, a bird.

It seems that Sony forgot, or at least has not yet gotten around to, programming the bird eye AF system with long-necked birds. I have only tested this theory with swans, but I would guess that it would struggle in the same way when faced with something like an ostrich or a flamingo.

Conclusion

The real-time-bird eye AF on the Sony a1 is a lot better than I was expecting it to be. With the vast majority of birds, it does a frankly incredible job of finding an eye within the entire frame and locking onto it wherever the bird moves. At times, it felt like I was cheating, and it certainly helped me to get a larger proportion of sharper images than I had previously experienced with my Sony a9 II or any other camera for that matter.

For wildlife photographers, this is a big step in the right direction, but it’s not perfect. At the moment the AI system that analyzes the subject in the frame has not been fed with enough information about non-standard bird shapes. It will fail if you point it at a long-necked bird like a swan, for example. I’m sure that Sony’s next firmware update will add some more “knowledge” to the bird AI in the a1, but for now, this is something to consider.

That said, if you happened to love photographing swans (or similarly shaped birds), you are in no worse of a position than you were before the a1 when there was no bird eye autofocus mode. And, as you can see from my images, you can still get great photos of these birds using the incredible standard tracking AF mode.

Finally, I would like to see Sony roll the bird eye tracking into the animal eye tracking mode. I’m guessing that for now, having it separated speeds up the AI analysis of the subject. But it can be a pain in the ass for a wildlife photographer who finds themselves in a subject-rich environment, constantly having to switch back and forth between bird and animal subject mode. If you find yourself presented with a chance encounter, it’s easy to raise the camera to your eye with the wrong subject selected.