For a long time, the only reason a camera would get an updated version of its firmware was to squash a few bugs or to modestly improve some aspect of performance. But things have changed. Fujifilm started the trend of adding or improving features via firmware with its X series of APS-C mirrorless cameras, and competitors have embraced the concept.

That includes Sony, which released Firmware 3.0 for its a7 III and a7R III cameras earlier this month. The firmware changes the way the existing Eye AF function works, and extends it beyond humans, to cats and dogs. (The firmware also adds an in-camera intervalometer, a basic feature that is long overdue. It works well, but doesn't require deep analysis.)

Eye detection for animals is good news for anyone who likes to photograph their pets, and Sony isn't stopping there. It plans on adding support for more animals via future updates, and will also be bringing the feature to its a6400 and a9 cameras later this summer.

Eye AF Without the Button—Regardless of Species

I tested the new firmware with the a7R III and a few cooperative—and furry—friends. Before we dive into talking about how well Eye AF works with animals, we should talk about the changes to the function in general.

Up until now, Eye AF required its own button press to activate. You'd press the button at the center of your camera's rear dial to actively search for eyes. It worked quite well, but was a little cumbersome to use.

With Firmware 3.0, Eye AF just works. As long as the eye you want to focus on is covered by the active focus area, the camera will find it. This extends to humans and animals. You will need to tell the camera whether it should be looking for a human or animal subject. I wouldn't be surprised if future updates eliminate the need to make the choice—Panasonic introduced a similar feature with its recent S1 and S1R cameras that doesn't require you to choose between people and pets.

I don't pretend to be much of a portrait specialist—I can frame a subject with competence, but if I'm not working with a professional model, I'm just about clueless when it comes to finding the perfect flattering pose. Eye AF doesn't make me a better photographer, but it gives me a little more freedom to experiment with angles when making portraits.

Even with the extra button presses that were necessary with earlier versions of the firmware, having a camera that finds the eyes and sets focus allows you to concentrate on making a better image. You can see the system working in real time in the viewfinder. It draws a big box around a detected face, and a smaller one when it finds an eye.

Machine Learning

The camera can do this because it knows what faces and eyes look like. It's something mirrorless models can do well because the camera is receiving so much information from the sensor—the a7 III has 24MP of information to work with for metering, subject recognition, and focus. The high-end Nikon D5 is an astounding pro camera for fast action, but its 180,000-pixel RGB sensor is only able to perform basic face detection.

Sony is using machine learning tools to inform its autofocus system. Existing models already had an internal database of images that told them what a human face and eyes looked like—in a general sense—and now it's building out the feature set by increasing the number of subjects that can be recognized.

We should be clear that this doesn't make the a7 III a learning camera. The database doesn't get better as you take more and more images, so there's little chance of your camera becoming self-aware and taking over your life in some sort of Black Mirror fever dream. Instead it's up to Sony to improve it, and dole those improvements out via firmware updates.

Does It Work?

All the fancy features in the world aren't worth anything if they don't work. Thankfully, after some testing with every pet I could manage to visit over a long weekend, I feel like I've got a good handle on the system, and can say it works pretty well. There's some room for improvement, but as you can see in the video below, it finds eyes on dogs and cats with good consistency and speed. The smaller green dots dancing around the camera's screen are the camera's standard focus system; the large green dot appears around the eye when it's detected, and tracks it as it moves.

When your pet is looking at the lens, there is absolutely no problem finding the eye. But there is a little bit of a struggle to identify subjects in profile from time to time, typically if you're trying to acquire focus initially with your furry subject in profile. If it picks up the eye first, and your pet then turns its head, the camera keeps a lock on the eye.

It's one thing to see the focus system in action, but how sharp are the eyes in images? There's more than just focus that goes into that determination—subject motion, your shutter speed, and the quality of the lens you're using are also factors.

I opted to test the feature with the a7R III, which uses a dense 42MP image sensor that absolutely requires you to put quality glass on to get exceptionally crisp results. Thankfully I had a few lenses handy that fit the bill. I tried Sony's own FE 70-200mm F2.8 GM OSS, along with the E-mount, but third-party, Zeiss Batis 2/40 CF.

Both of those worked without issue. I noticed some shots where the eyes weren't perfectly in focus, but they were an exception, not the rule. That's pretty fantastic, since I was doing my best to shoot with as shallow a depth of field as possible in order to really stress the focus system.

The Zeiss, particularly, with its f/2 aperture and near-macro focusing ability, is capable of making images with a very shallow depth of field. Take a look at the crop above; despite being a little grainy (the light required an ISO 4000 setting to maintain an 1/80-second shutter speed), you can see the reflection of a ceiling fan and my four-year-old niece in the cat's eye. It doesn't get any sharper than that.

Some Sony owners opt to use non-native lenses via an adapter. I wasn't able to test every adapter and lens, but did try the Canon EF 400mm F4 DO IS II USM along with the Sigma MC-11 adapter. In ample light, the combination focused quickly and accurately, netting portrait results like the uncropped image of Ginger you see below.

I did run into issues with the adapted lens in dimmer, indoor conditions. It's not often that you'll be able to use a 400mm effectively in a typical home, but my sister-in-law's studio apartment gave me plenty of working distance to get down on the ground and try it out on her black-and-white cat, Tobiko.

The problem wasn't with the Eye AF, but just hunting for initial focus in general. I found a twist of the manual focus ring to move the lens close was enough to get the autofocus system working right, but there is always going to be a little bit of a lag with an adapter, as it has to translate the commands the Sony camera gives a lens into a language the Canon lens can understand. Native lenses don't suffer—I was able to get the system to work with a cat that was practically in silhouette with the Batis 40mm.

As mentioned, Sony plans on adding support for more animals in future updates. But even without official support, I'd recommend turning it on for your next trip to the zoo. I spoke to some other photographers who found it worked on certain primates, and I'm able to get it to lock onto the eyes of some other species in Google image search results, including lions, tigers, and bears (oh my).

That's not a huge surprise—they're similar enough to dogs and cats for the camera to match them up. If you're more of a birder, or a fan of photographing lizards, amphibians, and other exotics, you'll have to wait for Sony to add them to the database. At press time, the cameras simply don't know where their eyes are.

Firmware 3.0 is available as a free download for owners of the Sony a7 III and a7R III.

Thanks to Lensrentals and Sigma for providing equipment to make this story possible. And special thanks to Charles, Duke, Ginger, Jace, Magnum, Max, Suki, and Tobiko for taking the time to pose.