This is a review for the pixel peepers, looking to maximize everything they can out of all 42MP in their Sony a7rii. If you're doing some digital zooming, a good lens can go a long way. So what is the difference between the top-of-the-line lenses for the FE-mount system? As you'll see below, very little.
I'm going to compare the amazing Carl Zeiss Batis 85mm f/1.8 to the gold standard Sony 90mm f/2.8 Macro lens. For fun, I've also thrown in the Sony 70-200 f/4 lens to compare the quality of this zoom lens at approximately 90mm.
For the first photo, I would like to compare bokeh on the Zeiss at f/1.8 VS. the f/2.8 maximum aperture on the Sony.
Left: Sony 90mm @ f/2.8 --- Right: Carl Zeiss 85mm @ f/1.8
As you can see in the photos, there is a difference, with the Zeiss creating a more pleasing blurred background. The difference is subtle, but is noticed.
The next set of photos we'll go into pixel peeping. We'll compare the two lenses at their matching apertures as well as the Sony 70-200 zoom option.
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Left: Carl Zeiss 85mm @ f/1.8 --- Right: Sony 90mm @ f/2.8
Left: Carl Zeiss 85mm @ f/2.8 --- Right: Sony 90mm @ f/2.8
Left: Carl Zeiss 85mm @ f/8 --- Right: Sony 90mm @ f/8
Left: Sony 70-200mm @ f/4 --- Right: Sony 90mm @ f/2.8
For fun - Left: Sony 70-200mm @ f/8 at 200mm --- Right: Sony 90mm @ f/8 blown up to be roughly the same 200mm field of view
Bonus Photos!
Sony Zeiss 35mm f/2.8 taken @ f/8
Sony 90mm f/2.8 macro photo of Jameson bottle label
So who wins for the ultimate in image quality? Well, that depends. At their maximum apertures, the Batis takes down the Sony 90mm. When the Batis is stopped down to f/2.8, it's actually a fair bit better than the Sony! After going down to f/8, the Sony comes out on top for pure resolution (although difficult to tell on the uploaded comparison photo). Coming in a very close third is the 70-200 which when stopped down has amazing resolution for a zoom lens. I've heard - but not tested - that the Sony 90mm can out resolve the Sony 24-240mm super-zoom, so I had to test whether it could miraculously out resolve the 70-200. Not by a long shot.
As far as pricing goes, the Sony 90mm is currently the cheaper of the two prime lenses and comes with the macro feature which I've found to be very useful. It also comes with the push-pull AF-MF switch, as well as sliders on the side to control AF/MF and Focus range. I have noticed that the focusing has been a bit slow at times, but when it hit focus, it's spot on.
The Zeiss Batis is VERY stylish, a bit smaller, but has no button controls like the Sony model. Also, to the credit of the Batis, the focus knob is the smoothest I've ever felt, and the LED screen makes manual focus a bit easier. Auto focus has been fast and accurate.
Final conclusion: If you're buying a prime lens for your Sony a7x body, you won't be disappointed regardless of your choice. They all come very close to matching the resolution of the sensor.
*A few side-notes on testing: All shots were outside on a beautiful day at iso 100. With tree and clouds, the shots do have slightly different lighting. Also, all shots were cropped from the center of the image. If there's interest, I might do a comparison of sides and corner resolution. All shots were taken with a tripod set to shoot after 2 seconds to reduce blur. All lenses had their optical lens stabilization turned off. Finally, all shots you are seeing are un-edited RAW photos, not JPEGs.
Thanks for looking. I hope this could be of some service to the people trying to decide between lenses.
-Aaron