Last Updated on 12/10/2025 by Chris Gampat
It finally happened, after a long weekend of shooting with the Sony a7V and both Viltrox and Sony lenses, the purple autofocus error flashed on screen and rendered the camera inoperable for a few power cycles. This issue is similar to one reported when using third-party lenses, but it was the first time I experienced it with Sony’s own lenses. Is this evidence of a bigger issue with the release of Sony’s new entry-level camera?
Sony a7V Issues with Third-Party Lenses
As we’ve previously reported, there have been issues reported with the a7V when paired with third-party lenses made by Chinese manufacturers. At the time, we hadn’t experienced the issue firsthand and largely dismissed the rumor as false. However, issues with third-party lenses are something that we’ve experienced in the past when testing those lenses on various Sony camera bodies. Most recently, I purchased a Viltrox AF 14mm AIR for my Sony a7III, and it was unusable until I updated the firmware for that lens. What I never would’ve expected was to run into this issue on a Sony lens.
Focusing Errors and the Sony a7V
One of the biggest features that Sony is promoting on the new a7V is the real-time subject detection AF, which is fine when it works. Over the weekend, I visited the Herald Square area to do some street photography and test the Sony a7V with a first-party lens, the Sony Sonnar T* 55mm F1.8 ZA. The Sonnar T* lens is one of the most beloved lenses for the FE-Mount and one of my favorites when shooting street on Sony. I remember this lens not just for the beautiful images it produces, but also for its rock-solid autofocusing capabilities, even when used with a Sony a7II. Imagine my surprise to find that many of my images were completely out of focus, even though I had seen the green AF indicator flash before I hit the shutter. To make matters worse, as the day progressed, I began seeing the purple indicator flash multiple times, rendering the camera inoperable.
Sadly, these issues persisted into the morning, during which I tried the camera with another lens, this time the Viltrox 35mm F1.2 LAB. With this lens, the first image was taken supposedly with the Star Wars ornament in focus, but the result was far from in focus. The second shot was better, but it came after much framing and re-framing. In both instances, the lens was shot wide-open and in Single Point AF mode. The last image I took for the morning (below) was taken after trying to get the camera and lens to focus on the traffic light at f/4.5. Not only did it fail to maintain focus, but it also ended up displaying the purple AF error and locking the camera, requiring me to remove the battery to reset it.
Signs of a Bigger Issue?
Where we stand today is trying to determine if this is a result of a firmware issue with the lenses, camera, or both. As I continue to test this camera, my biggest hope is that I have somehow ended up with a defective unit and I’m not experiencing “intended use” issues. The latter of which would signal a big shift in Sony’s relationship with third-party manufacturers. There are many photographers who have incorporated third-party lenses into their kits, and potentially losing even some first-party lenses would make this a bridge too far, even for me. We’ve reached out to Sony to determine the situation and why focusing appears to be achieved in the viewfinder and monitor but not in the final image.