Sony a6100 Autofocus & More

In my a6100 first impressions article, I didn’t cover the image sensor or autofocus performance. After using the camera for a bit I’ve got some thoughts in those areas.

Image Quality

The sensor is higher resolution (24 MP vs 20 MP) but has similar characteristics to the Z50. The noise levels are similar, the sensitivity is similar, the sharpness is similar. The shadows and highlights recover in a similar way. All in all, the a6100 provides very similar image quality to my Z50 and D500, which makes sense since Sony makes the sensors in those cameras as well.

The color is a bit different, maybe a bit more blue at times, sometimes a bit green, but that is somewhat related to white balance. The a6100 doesn’t capture white balance as accurately and tends to be cooler, but it’s easily corrected in post. The other part that is just a little bit different after correcting white balance can probably be considered “Sony color science”.

I had to adjust white balance, calibration, and color to get the green out of this image

Up until recently it wasn’t an issue, but the photos I took of the boys in the back yard had a really strong green to them that took several adjustments to take out. I shot with a Nikon at the same time and the images looked well balanced with no extra green. All in all it isn’t the end of the world but I can see what people mean when they talk about “Sony colors”.

Autofocus – Accuracy & Eye Detection

Autofocus works well, as expected. It locks onto eyes very fast and results in very sharp images. I prefer Nikon’s ability to easily toggle between the eye in focus, but the Sony is so much faster that it almost doesn’t matter. This makes a huge difference when photographing moving subjects (e.g. children, dogs) – sometimes they’ve moved ever so slightly by the time the Nikon has focus, resulting in a not-quite-so-sharp eye. Sony’s speed can keep up with moving subjects and turns out impressive results.

The uncropped image (left) is pretty wide, but when zoomed to 100% (right) the eyes are still sharp

Autofocus works really well tracking subjects, too. Place the tracking point over the subject and it will track them around the frame quite well, similar to 3D tracking on my Nikon DSLRs and much better than subject tracking on my Z50. Place the tracking point over a human subject with Eye AF on and it will automatically focus on their face and even their eyes as long as the focus point was placed anywhere an a subject it recognizes as human. It’s really, really, really impressive. It does’t work for animals on the a6100, but Sony’s $6,500 a1 supports it for animals including birds.

Eye AF works in many more modes than on the Z50 as well. The Z50 is limited to auto area mode whereas the a6100 can engage eye AF in any of its areas, including subject tracking. This provides a lot more flexibility when switching between human subjects, where auto area works fine, and non-human subjects, where I need to choose a focus point for composition. I can keep the camera in something like flexible spot for composition and still get focus on the eye in that area of the frame.

I’ve achieved some really awesome results with Eye AF on the a6100. I snagged some great, very well focused shots of the boys as they were running around playing with friends as well as some great portrait snaps. Children are always moving and they don’t want to wait for photos, so having confident autofocus is a must. The fact that the a6100 can focus on eyes nearly instantly is absolutely phenomenal. It far outperforms my Z50, even with a native lens. I see what all the fuss is about.

Autofocus – Interface & Limitations

The a6100 has a total of 10 different focus modes, versus the Z50’s six.

  • It’s wide mode is like the Z50’s auto area mode and will focus on whatever it thinks is most important in the frame. This is the only mode that the Z50’s Eye AF works, and the Sony works similarly in this mode. The Sony’s incredible speed and accuracy make this mode more usable than on my Z50 because I can trust it to focus on the right thing, even when it’s moving pretty fast.
  • Zone provides a box about ¼ the size of the frame that can be moved around. I initially found this mode intriguing as it does not exist on the Z50, but it’s rectangular shape requires too many button presses to move. I’d prefer if it were a strip that took up ⅓ of the vertical frame so that I could quickly focus left, right, or center.
  • Center is just that- a single focus point in the center that doesn’t move. This mode doesn’t exist on the Z50 and wouldn’t make any sense as pressing the center of the multi-directional button resets the focus point to the center. It’s necessary on the a6100 due to it’s annoying implementation of focus point selection that I’ll cover later.
  • Flexible spot offers a small, medium, or large focus area that can be moved around the frame. The small area is basically a single point and works like the Z50’s single point AF mode. The medium and large areas are similar in size to the Z50’s small and large wide area modes. I kind of like that Sony collapses them into one mode and lets me choose the size, but it makes selection a two step process versus the Nikon’s single level that’s easy to rotate through.
  • Expandable flexible spot is similar to the Z50’s dynamic area mode in that it will focus outside of the selected area if the subject moves.
  • In addition to all those modes are the tracking modes, which allow me to select the subject under the focus area and track it anywhere in the frame if it moves. This mode offers wide, zone, center, flexible spot, and expandable flexible spot as sub-modes, which are rather unnecessary and kind of confusing. I tend to set it to the large flexible spot sub-mode and leave it there. The Z50 only has one subject tracking mode, but I haven’t found all of Sony’s options to be that helpful.

The bevy of modes is great and all, but the most important difference between the Z50 and a6100 is that the a6100 allows Eye AF in all modes. The Z50 only offers it in auto area, which is extremely limiting if I’m photographing human/animal subjects and non human/animal subjects (which is often). Auto area is fine for things with eyes but generally doesn’t focus where I want on something like a flower. On the Z50 I have to keep switching modes to use Eye AF, but on the a6100 I don’t.

While the AF performance is awesome and the modes are very flexible, I don’t like Sony’s AF point selection interface at all. It requires entering AF select “mode” which only allows me to move focus points and disables other buttons until I press a button to lock in my selected point. Since I can still use the focus point and take photos without officially selecting it, I often get stuck in AF select mode and can’t change camera settings until I toggle out of it. It happens to me all the time and is really, really annoying. The Z50, all Nikons, and all other DSLRs that I’ve used, in fact, allow the AF point to be moved at any time without disabling any other functionality or requiring me to exit a mode.

Sony, this message is terrible

The only other issue I’ve encountered is that subject tracking doesn’t work with Animal Eye AF enabled. That’s fine, but Sony’s implementation doesn’t even allow me to select subject tracking when Anima Eye AF is enabled and doesn’t provide great messaging about what to do. It simply says “mode not available: subject detection: animal”, which doesn’t tell me that I need to turn that off in order to use it. I thought my camera was broken until I Googled it. I wish it would disable animal mode instead of preventing subject tracking completely.

In Summary

The a6100’s autofocus is everything I thought it would be. It’s fast, it’s accurate, and it’s flexible. With the right lenses, it works really, really well, but it’s hampered by an awkward AF point selection interface. The interface might be a little better on larger Sony cameras with more dedicated buttons but they all seem to assign multiple functions to the multi-directional controller that is used to move AF points so I’m not sure. What I do know is that the a6100 focuses much better than the Z50 in Eye AF and subject tracking modes. I will definitely be keeping this one for a bit to see what else I can do with it.

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