So back in 2015 i wrote a mini review on the Sony a7r2. Today I'll do another mini review, but of the Sony a9 with some comparisons to the a7r2. This mini review is from a portrait, wedding, travel, and general shooting point of view.
Here's a list of what I really liked about the Sony a9.
1. Eye-AF IMPROVED. This is nothing new to Sony users. The a9 improves on the a7r2 eye-AF. The eye-AF is stickier, detects eyes farther away (as well as face detect farther away), and it seems quite a bit more accurate. For my purposes, I changed both the priority in AF-S and AF-C to AF (vs the default of Balanced Emphasis). The a9 would acquire the eye much better than the a7r2 in AF-C. I didn't use eye-AF in AF-C with the a7r2 because i had better hit rates with AF-S.
2. a9 Customization. WOW. The button customization is FANTASTIC on the a9. I like to have my settings changed with a press of a button in any situation so I'm ready to capture the moment without the camera holding me back. THE a9 DOES THIS AND IS AMAZING. This is how I setup the a9. This setup for my needs and maybe a few of you out there too:
A. DEFAULT SETTINGS: APERTURE MODE, AF-C, Single Shot Mode, Lock-on AF expand flexible spot. I like to shoot in aperture mode most often. I also use eye-AF a lot and trust AF-C so I keep it at that. My AF-ON button is my eye-AF button. I chose these defaults settings because I'm taking photos of people most often and will be using eye-AF.
B. Recall Custom hold 1: APERTURE MODE, AF-S, Single Shot Mode, Flexible Spot. My AEL button was changed to "Recall Custom hold 1". You're able to save settings such as aperture, shutter speed, drive mode, ISO, focus mode, focus area, etc. The reason this is amazing is because with a touch of a button (AEL), I could focus with the settings of AF-S. This way i can capture objects and recompose instead of using AF-C that I currently have the camera set at. I don't like to shift the focus point since it delays how I shoot. On the a7r2, I would have to set up custom dial modes 1 and 2 and switch to those when I want to use those settings. With the a9, it's MUCH faster to switch to the settings I want, all with the press of a button..
C. Recall Custom hold 2: APERTURE MODE, AF-C, Low Continuous Shooting Mode, Wide Focus Area. These settings were bound to C3. The sole purpose of this button was to change from Single Shot Mode to Low Continuous Shooting Mode. This way I'm ready to capture a sequence of images.
E. Iso Auto Min SS. I bound this to C4. I use this to quickly change shutter speeds depending on what situation I'm in. If i can get away with lower shutter speeds, I'll change it to Slow or Slower. If I need the shutter speed to be fast, I'll change it to Fast or Faster. For general shooting, Standard is fine with me.
F. Live View Display and Shutter Type. I like to shoot flash a lot so I want to quickly change my settings to move over to a flash setup or vice versa. I bound those two settings to C1 and C2. As you might know, flash can only be used with the mechanical shutter on the a9. For most other situations I will use the electronic shutter. I also turned EFCS off when I have the mechanical shutter turned on; there's an issue where the bokeh isn't as nice with the EFCS on while using the mechanical shutter on the a7r2. I'm not sure if the a9 has the same issue, so I turned it off anyway.
G. EXAMPLE SCENARIO: Let me give you a scenario where I would use my setup. I'm out shooting portraits and so my default setup of aperture mode, AF-C, single shot mode, eye-AF would take care of 95% of my people shots. In between shots I feel like I want to take a photo of an object like a tree. I can press my AEL button to switch over to AF-S and flexible spot to focus and recompose as I wish. Soon after, a dog comes by and I want to capture it running. I'll press C3 and now I'm in AF-C, low continuous shooting mode, wide focus area. With this setup, I can cover 99% (maybe 100%?) of all situations I want to capture. It might differ for you, but it works for me.
3. Operation Speed. This has improved A LOT from the a7r2. The start-up speed could be slightly faster, but it's good enough and had no issues with it. Switching settings and fiddling with all buttons on the camera was smooth. The overall operation speed could still be slightly faster in the age of PCI-E SSDs and instant everything, but I was very happy with the performance.
4. Resolution. I like to shoot portraits and travel stuff so I personally want to have larger file sizes and can print medium or large prints without any worry. I couldn't go back to the 24 megapixel sensor. This was the only issue that held me back from grabbing the a9. If they built an a9r with a 42 megapixel sensor or greater, I'm buying it immediately. I don't care for the 20 fps as you may have noticed above.
5. Battery Life. It's amazing on the a9. I would probably only need to own 2 batteries. For the a7r2, I own 5 batteries. Much improved.
6. Memory card door. This has been upgraded on the a9. It has a latch type mechanism now. The a7r2's memory card door and can be bumped and will sometimes open up.
The Sony a9 fixes all the problems I had with the Sony a7r2. I was so close to switching over to the a9 from the a7r2, but the 24 megapixels held me back. I really hope an a9r pops up soon, because that's what I'm buying. The a9 would be the perfect camera for me if it had a higher resolution sensor and a minor bump in operation speed. I'll be waiting for the a9r.
EDIT! 12-3-17: I wrote this awhile ago and left the post unpublished. The a7r3 was announced. Just got it in and love it.