Image quality comparison: The Sony A7s II vs. the Olympus OM-D E-M5 Mark II

Bar Scene - Kerrville, Texas (Shot with Olympus E-M5 II - before)

Bar Scene – Kerrville, Texas (Shot with Olympus E-M5 II – before)

Bar Scene - Kerrville, Texas (Shot with Sony A7s II - before)

Bar Scene – Kerrville, Texas (Shot with Sony A7s II – before)

I did a quick, unscientific test and I wanted to share the results with you. This image quality comparison is a followup to my Sony A7s II review. During that one night test at Precision Camera University, I snapped these photos with the Sony and my Olympus. How do they compare? Read on to find out.

First, a few caveats. I shot one photo each with both cameras. This is not going to be a meticulous evaluation, rather, just a quick, real word test of the low-light capabilities of both cameras. I’m quite familiar with the Olympus E-M5 II, it’s currently my most used camera. I wanted to see how the Sony would do under the same conditions.

Is this fair test? No. The Sony A7s II is a full frame camera and with the 35mm f2.8 lens, costs about $3800. While only 12MP, it’s known to be exceptionally good in low light. The Olympus OM-D E-M5 Mark II with the 17mm f1.8 lens costs $1600. It sports a considerably smaller micro 4/3 sensor at 16MP.

I stood in the same location and used auto exposure and auto white balance and took these two snap shots. I shot both in Sutter Priority with a +1/3ev exposure compensation. I did not attempt to match exposures rather, I tried to optimize image quality.

Olympus OM-D E-M5 Mark II
ISO: 2,500
Aperture: f1.8
Shutter speed: 1/30 of a second
Exposure Compensation: + 1/3ev

Sony A7s II
ISO: 6,400
Aperture: f2.8
Shutter Speed: 1/80 of a second
Exposure Compensation: + 1/3ev


The photos above are unedited and came right out of the cameras, as is. As you can see, the Olympus exposed brighter than the Sony. That’s been my experience using both cameras. I’ve noticed that the Sony tends to expose darker and I often dialed in +1/3 to +2/3 exposure compensation. I should have shot the Olympus without any exposure compensation, which would have dropped the ISO to 2000 and slightly improved the picture quality.

The Olympus color is warmer with more yellow and the Sony’s cooler and a bit more flat. That is also consistent with my observations using the Sony. Neither is better than the other color wise, though my personal tastes tend to run to warmer tones.

Post Processing

Next, I post processed both photos to match each other — as closely as possible. I shot the Olympus in RAW and the Sony in RAW + JPEG. However, since I didn’t have a A7s II RAW converter, this analysis was done with the Sony JPEG. Using a JPEG did negatively affect one area, which I point out below. Let’s go pixel peeping. Something that I usually don’t do, but it’s interesting for this test.

Center of the frame
Olympus - Center

Olympus – Center

Sony - Center

Sony – Center

Looking near the center of the frame, you will notice that the Sony is sharper in these 100% magnified images. The Sony has less noise, even when shot at ISO 6400, which I expected, given that it’s known for high ISO performance. I was surprised that the Sony was a lot sharper, however. This goes to show that megapixels is not everything. The Sony, which has a 12MP sensor shows more detail than the 16MP Olympus.

So why is the Sony sharper than the Olympus? There can be a number of reasons, here’s several I thought of.

1. Motion Blur: At 1/30 of a second, there is more chance that the slower Olympus shutter speed will show more blur than the 1/80s Sony shutter. Even with image stabilization (IS), there can still a be small amount of camera movement. Also, IS does not stop the people from moving. The combination of camera and people movement can rob a photograph of critical sharpness. A look at the black board in the background revels closer sharpness results.

Why not shoot the Olympus at a faster shutter speed? In better light, this would be a good option. I purposely slowed down the shutter to reduce the ISO. If I shot the Olympus at 1/80 of a second, the ISO will need to be 1 1/3 stops more sensitive, which would put it at ISO 6400. With the Olympus, I ideally like to stay at ISO 3200 and below, though I do shoot up to 6400, but only when I absolutely have to. This is where the high ISO performance of the Sony shows its advantage. I can shoot at higher shutter speeds, even in darker conditions.

2. Lens Sharpness: Certainly the sharpness of the lens can also be a key reason. Lenses tend to be sharpest 1 to 2 stops from their largest aperture. In this Olympus photo, I shot “wide open”, the largest aperture of f1.8, which is not the sharpest setting on the lens. I also shot the Sony lens wide open at f2.8, however, all things being equal, it’s harder or more expensive to make a sharp, larger aperture lens. In addition, the Sony can simply be an all around sharper lens. It does list for $300 more than the comparable Olympus lens.

3. Improper Focus: It is possible that I didn’t nail the focus exactly. Though, this seems less likely since parts of the image are very sharp.

4. Image Processing: Images are altered by the image processor whether in JPEG or RAW. Noise reduction and other manipulations by the camera might reduce sharpness. In addition, for RAWs, the computer’s RAW converter may also play a role. I used the RAW processor that is built in the Macintosh’s operating system and accessed through Aperture 3 application. RAW converters from Adobe and Capture One, for example, will yield a different look.

5. Anti-Aliasing Filter: Both cameras, I believe, have an anti-aliasing filter, which is designed to blur the image slightly. The strength of the anti-aliasing filter may, however, favor one camera over another.

On the Right
Olympus - Right

Olympus – Right

Sony - Right

Sony – Right

Looking on the right side, at Nate’s shirt and tie, the sharpness looks similar, though I still give Sony a slight edge. The bigger issue is the splotchy dark purple patterns you see on Nate’s arm in the Sony image. The post processing to brighten the image created this unwanted effect — a consequence of using a JPEG. If I used a RAW, I’m almost certain that I wouldn’t get these artifacts. RAWs have a lot more dynamic range than JPEGs, which allow for more aggressive post processing without negative effects.

On the Left
Olympus - Left

Olympus – Left

Sony - Left

Sony – Left

The image sample from the left shows some major sharpness differences. Beyond what was discussed above, I believe much of this due to the lens. Lenses are sharpest in the center and become softer at the edges. This particular copy of the 17mm f1.8, which I borrowed from Olympus, seems to have an issue on the top left. The other corners are a lot sharper. Overall lens sharpness, as well as corner performance, will very by sample. The sample of the Sony FE 35mm f2.8, in comparison, is very sharp throughout the entire field.

The other point worth noting is the over exposure of Jimmy’s white shirt, in the Olympus image. I mentioned that I should have taken this photo with no exposure compensation. Even shot in RAW, I was not able to recover this overexposed area. RAWs (and JPEGs) typically work better brightening shadows instead of recovering highlights. Also, larger sensors usually have more dynamic range. Potentially, an A7s II full frame RAW might be able to recover more detail than from a micro 4/3 RAW.

The Big Picture

Now that we analyzed parts of the image, let’s look at the entire photograph. After post processing, I think the color and exposure look remarkably similar and I’ve cropped the Olympus photo to the same 2 by 3 aspect ratio as the Sony. At these small sizes, you might not know that they were taken with two different cameras.

Bar Scene - Kerrville, Texas (Shot with Olympus E-M5 II - after)

Bar Scene – Kerrville, Texas (Shot with Olympus E-M5 II – after)

Bar Scene - Kerrville, Texas (Shot with Sony A7s II - after)

Bar Scene – Kerrville, Texas (Shot with Sony A7s II – after)

That’s the thing that many people don’t think about. It’s not just the camera, it’s the image output size you need to consider. Do you just post small images to Instagram or slightly larger ones to Facebook? Then the quality of the camera really doesn’t matter very much, especially in good light.

Click on the images to see a larger version. At the larger size, you may begin to appreciate the A7s II’s sharper image. Do you print your photographs? How large? Even a 13 x 19 inch print might not show significant differences.

Pixel Peeping like this can be fun or an obsession for some. But does it truly matter? Compelling content trumps all technical considerations. And when considering technical factors, I think color and exposure are more important than sharpness and noise. That said, in this test, there is no question that the Sony A7s II created a sharper image than the Olympus OM-D E-M5 Mark II. I’m very impressed. Yes, it’s “only” 12MP but it’s a very sharp and detailed 12MP.

Finally, how much post processing do you plan or want to do? It took a bit of fiddling to get the colors to match this closely. I prefer the out of camera Olympus colors and exposure. Though, I fully admit that this is a very personal choice. Even if you shoot in RAW and have the ability to post process, it’s always nicer to have the default color and exposure match your preferences.


There is no question that I’m seduced by the possibility of shooting effortlessly in low light. That’s where I like to play. The Sony A7s II raises the headroom of what’s possible. Over the years, with the improvements in micro 4/3 and using various techniques, I’ve been able to shoot it lower light conditions. But, of course, it comes with a price. I balance the limitations. And the tradeoffs I make change based on the conditions. What I create usually works but the A7s II has shown me, with less effort, I can create a superior image. Sure, it requires some additional post processing, but that’s something that I don’t mind doing.

The Sony comes with a price too. The camera and two lens set (FE 28mm f2 and FE 35mm f2.8) run over $4000. The camera also is heavier and larger than the Olympus. Plus, while certainly a well built camera, it lacks the refinement that I find in the E-M5 Mark II. Read my Sony A7s II review, for more details.

Photography shouldn’t be about ultimate image quality or pixel peeping. I, like everyone else, need to answer the question, “What is my target output?” Historically, I’ve judged output, at full size, on my Apple 27” Thunderbolt display. On that computer monitor, the A7s II looks slightly better but not enough to justify paying $4000+. The calculus can certainly change in the future. A breakthrough technology or a massive price cut will, no doubt, spin my analysis wheels again.

How about you? What is your target output? Would a full frame low-light camera truly make a difference in your work and creativity?

Please support this blog by clicking on my Amazon Link before buying anything.

9 thoughts on “Image quality comparison: The Sony A7s II vs. the Olympus OM-D E-M5 Mark II

  1. I was curious about this Andy…nice quick analysis of both cameras. The Sony seems to have jumped ahead even of Nikon/Canon cameras with delivering outstanding images. But as you say….as what cost. Thanks.

    1. Thanks for you visit and comment, Carlos. From what I know, Nikon’s image quality and low light performance is quite good, though it’s DSLR only. Canon still appears to be behind.

  2. I just got the OMD E-M5 — not the II, the original. I can see the difference between my various lenses much more obviously on this camera than on any of the PLs that I have. I have mostly primes and they are MUCH sharper than any of the telephotos. Right now, the one that seems to be the all around sharpest is the 25mm 1.8 and in second place, the 45mm 1.8. Not the most flexible of lenses, but I haven’t found a telephoto that isn’t soft in some segment and pathetic in low light.

    1. Congratulations on the E-M5. I heard the 25 1.8 is a fantastically sharp lens and the 45mm is no slouch either. Olympus has an excellent telephoto, the 40 -150 f2.8 Pro, which I heard might be one of their sharpest lenses. Unfortunately. it’s big and expensive, at least compared to the typical mirrorless lenses.

  3. Really enjoy your blog. Actually been looking for this type of comparison for a while, as I’ve been thinking of getting an A7S, but wondering how a 12MP full frame would compare to m43 in terms of IQ. I’m primarily an Olympus m43 user, but have owned Nikon DX & FF, Fuji X, and Sony A7 in the past. The A7 autofocus was a little sluggish for me, but I heard that the A7S is a little faster (single point focus – not tracking) and I really like the low light capability. Wondering how you found the AF of the A7SII. From what I understand, it might not be too different from the A7S. Also, wondering why the shutter speeds for the two cameras were so different. Doesn’t the A7SII have IBIS too? Does it just not work as well? Finally, just wondering if you think the m43 would have done better with a sharper lens. I also have the 17mm f1.8, but in terms of sharpness, it might not be the best of the primes (I know you were trying to match field of view though).

    1. Thank you, Ed. Glad you enjoy the blog.

      First, if you haven’t already, please read my review of the Sony A7sII

      The shutter speeds were different on purpose. I general, I prefer using a faster shutter speed, which will reduce motion and subject blur and create sharper images. I used a slower shutter on the Olympus because, if I used a faster shutter, the ISO will become unacceptably high. That’s the advantage of the Sony A7sII. Since the high ISO performance is so good, I can use a faster shutter speed without worrying about image quality (within normal limits)

      The A7sII also has IBIS though I didn’t test it much since, I didn’t have to use a slower shutter speed.

      Yes, a different, sharper lens would produce better results on the Olympus, particularly on the left side, which was soft (at f1.8) on this particular 17mm f1.8 lens. I hear the 25mm is fantastically sharp, for example.

      I used the 17mm because 1. I wanted the same focal length between both cameras. 2. It’s the lens I had. 3. I like the 35mm equivalent focal length so I shoot the 17mm all the time.

  4. I, too, think that the Sony A7II is an amazing camera but I have to come back to the reason that I chose the OMD E-M1 when both cameras were new on the market is size and bulk. Certainly I want quality too but for the sizes I print on paper up to 17×22 I’m happy with the results. AND I carry the camera more because it is lighter and smaller. I lose in some areas but the most important thing is that I can keep photographing.

    1. Hi Billie, The reality is, for most people, the results will be similar. Pixel peeping will certainly show the differences, as I have done in this post. But if you look at the entire photo, at these web sizes, the differences are very minor. Even full size on my 27″ monitor, the differences are certainly noticeable but not earth shattering.

      If I was a Pro photographer, shooting a lot of low-light events, the A7sII will be my go to camera. But for what I do, the reality is that the Olympus is good enough. I get the benefit of a smaller, nicer built and stylish camera with a lot of lenses which is considerably less expensive.

      Note, the test was with the Sony A7sII not the A7II. I’m sure the A7II results will not be as dramatic in terms of low light performance.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.