While reviewing the Sony A7 II, I had a chance to test and play with every Sony FE lens made as of April of 2015. The list includes the following lenses: Sony FE 35mm f/2.8, Zeiss Loxia 35mm f/2, Zeiss Loxia 50mm f/2, Sony FE 55mm f/1.8, Sony FE 16-35mm f/4 OSS, Sony FE 24-70mm f/4 OSS, Sony FE 28-70mm f/3.5-5.6 OSS and Sony FE 70-200mm f/4 OSS. Since I also simultaneously had the Sony A7R and A7S bodies (reviews to follow soon), I decided to measure MTF performance of each lens using Imatest and see how they perform individually. While I am planning to review all of these lenses in detail within the next few months, I thought putting together some data for our readers might be helpful, perhaps for those of our readers who either already own the A7 system, or those who are planning to invest in it. The below numbers are based on two different samples of each lens (I always do my best to test at least two due to sample variation) and the numbers I present are for the lens that showed the best results. Unfortunately, due to the shutter shock issue of the Sony A7R camera, I was not able to reliably test the Sony FE 70-200mm f/4 OSS lens, particularly at anything longer than 100mm. I will have to retest that lens when Sony adds electronic front curtain shutter feature to the A7R, or releases a newer 36 MP+ body with built-in EFCS (yes, the shutter shock on the A7R is pretty significant). I have not yet tested the newly announced Sony FE lenses, so I will test those separately as soon as I get my hands on them.
The below lenses are listed in the order of preference, from best to worst.
1) Sony FE 55mm f/1.8
The Sony FE 55mm f/1.8 is a stellar performer, with superb, even sharpness across the frame. While its center resolving power is not as great as on the Sony FE 35mm f/2.8, it gets pretty darn close in comparison and has much better mid-frame and corner performance:
When it comes to sample variation, the Sony FE 55mm f/1.8 seems to be pretty consistent. Both lenses did quite well in Imatest and did not show any serious decentering and other optical issues.
2) Sony FE 35mm f/2.8
This small and lightweight lens is an absolute gem, a proof that lenses designed for mirrorless cameras with a short flange distance can outperform similar focal length lenses created for DSLR cameras. The Sony FE 35mm f/2.8 outperforms every 35mm lens I have tested to date, except for the Sigma 35mm f/1.4 Art, which it matches at f/4. Take a look at the below graph:
Sample variation is well under control. I tested a total of three samples of this lens (one in 2014 and two in 2015) and all three were very close optically. Keep in mind that the resolution is really good in the center, but mid-frame and corner performance do suffer in comparison to some other 35mm lenses. Vignetting is also rather strong on this lens.
3) Zeiss Loxia 35mm f/2 Biogon T*
The Zeiss Loxia 35mm f/2 feels nothing like the Sony 35mm f/2.8. It is noticeably heavier, has an all-metal barrel (vs plastic) and hood and feels completely different to handle. Unlike the Sony 35mm f/2.8, it has an aperture ring, so you control aperture directly through the lens (there is no way to do it through the camera). The focus ring is smooth and very responsive. The moment you start moving the focus ring, the camera goes into the zoom mode automatically, allowing you to get precise focus. Overall, it feels and acts like a much higher-grade lens than the Sony-made version. Let’s take a look at its MTF characteristics:
I have only tested one sample of this lens and it turned out to be great. No decentering or other optical issues.
4) Zeiss Loxia 50mm f/2 Planar T*
The Zeiss Loxia 50mm f/2 is another beautiful lens, which is crafted very similarly as the Loxia 35mm f/2. In fact, if you buy the 35mm f/2 for your Sony A7 series cameras, it makes sense to get this lens as well, since you will most likely fall in love with both. And here are the MTF numbers produced by Imatest:
Just like the 35mm f/2, I have only tested one sample. No decentering or other serious defects were detected. Zeiss quality speaks for itself.
5) Sony FE 16-35mm f/4 OSS
The more recently released Sony FE 16-35mm f/4 OSS is a superb lens as well, with very impressive resolution characteristics between 16mm and 28mm. Its performance drops quite a bit on the long end at 35mm, but it is still not bad. There is a bit of field curvature at the wide end. The lens is heavy and big, but it balances well on the A7 series cameras, particularly on the A7 II. Let’s take a look at the MTF figures:
The lens performs incredibly well at its widest focal length of 16mm. The corners are a bit weak wide open, but look pretty good when stopped down to f/5.6.
As you zoom in towards 24mm, the corners look a bit better now.
And at 35mm, the lens shows a visible drop in sharpness, particularly in the corners.
Sample variation is somewhat of a mix. The first sample had a decentering issue and showed poor performance on the left side of the frame. I had to move the setup to the left to fight against the decentering problem and even then the numbers did not quite match what the second sample showed. Complex lens designs make it hard to produce very consistent performance from lens to lens, but I would strongly encourage anyone that wants to buy this lens to test it and make sure that it does not have any serious optical issues.
6) Sony FE 28-70mm f/3.5-5.6 OSS
The Sony FE 28-70mm f/3.5-5.6 OSS is a kit lens that comes with the Sony A7 / A7 II cameras. Although it is a plastic and lightweight lens, it is actually quite a good performer, especially on lower-resolution Sony A7 cameras like A7 / A7 II. Here is how the MTF performance looks like at 28mm:
Not bad, but it cannot get close to what the 16-35mm can do at 28mm. Let’s take a look at 35mm:
And here we can see that the lens is actually quite good in the center. However, due to field curvature, the lens suffers from rather poor mid-frame and corner performance.
Performance slightly improves at 50mm, showing good results overall. And here is 70mm:
Similar to the 16-35mm f/4 OSS, the 28-70mm f/3.5-5.6 OSS performs the worst at its longest focal length. We can see that there is a pretty significant drop in sharpness throughout the frame. Performance is at its highest at the widest aperture of f/5.6, so stopping down only improves the extreme corners.
I also tested three samples of this lens, one in 2014 and two in 2015. All three were decent lenses, but showed variance in performance. The first sample was quite good, the second was average and the third had decentering issues past 50mm. It is expected to see more variation in cheaper lenses, so this is not a surprise. Still, when you see the resolution figures below for the 24-70mm f/4 OSS lens, you will understand that the 28-70mm presents a much better overall value.
7) Sony FE 24-70mm f/4 OSS
The mid-range Sony FE 24-70mm f/4 OSS zoom lens was released initially together with A7 and A7R cameras as a general-purpose lens. Let’s take a look at the resolution performance characteristics of the lens:
Ouch, the 24-70mm f/4 OSS is weaker than the 28-70mm OSS at the shortest focal length – only its mid-frame performance is better.
And zooming in to 35mm does not improve the situation. Unfortunately, the lens performance is still quite poor.
The same thing happens at 50mm, with the 28-70mm showing better overall performance.
At 70mm, the 24-70mm gets a bit better, but it is still pretty bad. Similar to other zooms, 70mm is the worst focal length for this lens.
While I only tested two lens samples, this one came out to be the worst of the bunch. Not sure if Sony was simply rushing these lenses into production, or perhaps the optical design of the lens is just poor, but boy…the first sample of the 24-70mm was terrible. Both poor MTF performance and decentering issues were present, making testing this lens a nightmare. The second sample had weird optical issues in one particular corner of the frame, but it was not a bad one to test with. MTF performance on both was discouraging and the amount of distortion exhibited by the 24-70mm is outrageous. You don’t see it on the camera, but once you put files into Lightroom, you will see it immediately. Strong barrel distortion at 24mm transforming to pincushion at 35mm, turning to strong pincushion at 70mm and staying like that all the way until 70mm. The 28-70mm also shows signs of distortion, but given its price, it is not unexpected. For $1,200, the 24-70mm should have been much better.
Perhaps both lenses were lemons, but looking at how poorly the 24-70mm lenses are built (the front part of the lens is wobbly when extended, feels plasticky, etc), it surely does not deserve the Zeiss name on it. It feels like a cheap superzoom lens, not like a professional 24-70mm. Serious disappointment. I am planning to test another copy of this lens to see if it might be better optically…