Olympus 12mm F/2.0 lens, corner test

The upper right corner of my Olympus M.Zuiko 12mm F/2.0 lens seems to be the weakest of the four corners.

The comparison between first two crops demonstrates that the lens has field curvature. When focusing in the center at F/2.0, the corner is pretty soft, but then when you focus using the focus point closest to the upper-right corner (the second crop), the corner gets quite a bit sharper.

Stopping down the lens to f/5.6 only results in a slight increase in corner sharpness. That’s as sharp as the corner gets. It never gets tack sharp.

Now one could say that normally there’s nothing important in the extreme corners of the photo, or that on a 12×18” print you wouldn’t notice the issue at all unless you examine the print with a magnifying glass.

But I think that when a lens sells for $799, and on top of that only has a modest (for a prime lens) f/2.0 aperture (which is only equivalent, approximately, to an f/4.0 full-frame lens), there’s an expectation of extreme image quality, and this lens falls short of being a $799 lens, especially when compared to the 12-40mm f/2.8 “PRO” zoom which is only two hundred dollars more expensive and has sharper corners.

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Read my previous 12mm F/2.0 post: Olympus 12mm f/2.0 lens, first impressions review

Olympus 12mm f/2.0 lens, first impressions review

If you have been reading my blog, you may recall that I bought the Olympus M.Zuiko 12mm f/2.0 lens with my Pen-F last week. Olympus was having an August sale where the prime lenses were $300 off list price with the purchase of a Pen-F.

12mm f/2.0 on Micro Four Thirds is equivalent to 25mm f/4.2 on a full-frame camera if you crop the Micro Four Thirds image to a 3:2 aspect ratio. (See my post on the Micro Four Thirds focal length multiplier. )

The lens can be purchased in two colors: black and silver. I chose black, and I am nearly certain that I made the right choice. The black 12mm f2 is the most beautiful Olympus lens that I own. It looks more elegant and retro than the silver 17mm f/1.8 which I also own. I think this partially has to do with the shape of the lens; the 17mm has a more modern-looking shape. But I also think that silver is just too flashy and makes the camera look more modern, even though I am aware that silver lenses were actually popular in the 1950s. Ironically, 1950s Leica was probably trying to make its cameras look futuristic, but today we want cameras that look like they’re from the 1950s. (Because after you strip away all of our high-tech gadgets like computers, smartphones, digital cameras and high-speed internet, underneath the 2010s suck compared to the 1950s.)

The black 12mm f2 looks awesome on the black and silver Pen-F. After using the E-P5 with the huge 12-40mm, the Pen-F, with the small 12mm lens and a built-in EVF instead of a big ugly plastic add-on EVF hump, has such a lightness and ease of use about it. Using it gives you such a feeling of joy.

Some readers are no doubt wondering, by this point, “but how does it function as a lens?” As a lens, it’s a little bit disappointing. Not because it’s a bad lens. It’s definitely sharper than the 9-18mm at the same focal length, and far superior to the Panasonic 14mm f/2.5. If I did not know about the 12-40mm “PRO” zoom (which people didn’t in 2011 when this lens was first introduced, because the “PRO” zoom didn’t exist back then), then I might proclaim “finally, a sharp wide-angle lens!”

This lens is perfectly useable at f/2.0, as long as you don’t expect super-sharp corners. The Olympus primes are generally not intended to take pictures of brick walls wide open, but if what you focus on is in the central two-thirds of the frame, then you will get a sharp picture. But not as sharp as the 12-40mm zoom at f/2.8. In fact, I am pretty sure that at all matching focal lengths, the 12-40mm is very slightly sharper than the 12mm f2 in the center, and more noticeably superior in the corners. If you want across-the-frame sharpness, then you need to stop down the 12mm prime to f/5.6.

I would say that, in the corners, compared to the 12-40mm zoom, the 12mm prime has less contrast and is softer. The 12mm also gets a little bit of purple fringing in the corners if there are tree leaves or branches there, while the 12-40mm is totally free from purple fringing. Also, I think that the 12mm prime has a little bit of an astigmatism. This is noticeable with certain subjects, like brick buildings, and it causes the edges of the photo to have an unpleasant nervous look. The 12mm has less lateral chromatic aberration, so that’s one benefit of the 12mm. (But lateral CA is automatically corrected in Adobe Camera Raw if you check the box, so it’s not an especially big benefit.)

I think that the 12mm has some field curvature, which means that the corners are front-focused relative to the center. This is a lot more prominent on the 17mm f/1.8 lens, but I still think it’s a good idea, when using this lens, to not use the focus and then recompose method. (Luckily you don’t have to do that on Olympus cameras, which have focus points all over the frame except for the extreme edges.) Also, corner sharpness when focused at infinity may be improved slightly by using a focus point near the corner (thus causing the center to be focused a little bit past infinity). I always use that method with the 17mm lens to get sharper corners without any noticeable detrimental impact on center sharpness.

The 12mm prime is slightly wider than the 12-40mm at its widest. So maybe the 12-40mm is really a 12.4-40mm. Or maybe the 12mm prime is really an 11.5mm prime.

Should you buy this lens? Considering that this lens has a list price of $799, and the 12-40mm zoom is only $200 more than that, the zoom is a much better value. Buy this lens because you want small and light and are sure that you want this focal length (which is a more challenging focal length than 17mm). Buy this lens because it looks so beautiful on a Pen-F. Buy this lens because you get an extra f-stop over the 12-40mm. (But unfortunately, even with f/2, you won’t get much bokeh on this lens. If you want wide-angle bokeh, that’s an area where full-frame shines over Micro Four Thirds.) Don’t buy this lens because you think that a prime lens means superior image quality over a zoom lens. It doesn’t. My overall conclusion is that this lens is overpriced at $799, overpriced at its current sale price of $699, and yes, even for $499 it’s still kind of expensive.

Also note that Olympus is too much into nickel and diming its customers to include a lens hood with this lens, making the value proposition slightly worse. Being too cheap to buy the official Olympus lens hood for $59.95, I bought a Sensei 52mm wide-angle screw-in rubber lens hood for only $6.95. Used with a 46-52mm step up ring, over a 46mm Firecrest UV400 filter, there is no vignetting. However, the rubber lens hood does significantly ruin the aesthetics of the lens, and the how the lens looks on the camera is one of its main selling points.

If you are looking for the most amazingly impressive wide-angle image quality in a small camera, plus bokeh, I’m afraid that the camera for you is the Leica Q rather than any Micro Four Thirds camera. Yes, I’ve pixel peeped at some Leica Q samples posted on the internet, and I am really blown away by the quality of that lens. It’s head and shoulders above the Olympus 12mm prime. But that Leica Q costs $4250, and that’s pretty expensive. Remember what I said a few days ago when I bought the Pen-F: you don’t need a new camera, it’s just G.A.S.

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I haven’t had much opportunity to actually take many pictures with this lens. And I don’t have any which demonstrate the benefits of f/2. The photo above is a quickie of 7th Avenue in Manhattan which I took while walking home from work earlier this week. I cropped it to my favorite aspect ratio of 3:2, but otherwise there are no other lens corrections.

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Read my next 12mm F/2.0 post: Olympus 12mm F/2.0 lens, corner test

What’s the true focal length multiplier for Micro Four Thirds?

It is often stated that Micro Four Thirds cameras have a 2.0 focal length multiplier. In other words, a 14mm lens on Micro Four Thirds is said to be equivalent to a 28mm lens on a full-frame camera.

The problem with this comparison is that full-frame has a 3:2 aspect ratio, while Micro Four Thirds has a 4:3 aspect ratio. If you crop one picture or the other so that the two pictures have the same aspect ratio, you will get a different focal length multiplier.

If you crop the full-frame image to 4:3, then the focal length multiplier is 1.85. So a 14mm lens on Micro Four Thirds becomes equivalent to 26mm on full-frame.

If you crop the Micro Four Thirds image to 3:2, then the focal length multiplier is 2.08. So a 14mm lens on Micro Four Thirds becomes equivalent to 29mm on full-frame.

Kit lens photography

M.Zuiko 14-42mm IIR @21mm f/7.1

After my previous post where I advised people to show that they are skilled photographers by using a cheap camera with a kit lens (because any bozo can take good pictures with a ten-thousand-dollar camera), I took out my kit lens and took this photo.

Physically, I love how small and light the Olympus 14-42mm IIR is compared to the much larger and heavier 12-40mm f/2.8 “PRO” lens. It doesn’t bother me at all that the lens is made from plastic and not metal.

But then when I peeped at the pixels, and while the sharpness was pretty good, I was disappointed to see a lot more fringing than I see with any of my other more expensive Olympus lenses. But still better than using an iPhone.

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History lesson: the tower with the clock is the Met Life Tower, which was the tallest building in the world from 1909 to 1913 when the Woolworth Building surpassed it.

Is Leica a lightweight camera for landscape photography while hiking?

I read on another blog (I read it here) that a Leica M is a good camera for taking landscape photos while hiking because it’s allegedly light weight.

Let’s see how Leica stacks up against an Olympus Pen-F with the 12-40mm f/2.8 “PRO” lens.

Leica M (Typ 262): 21.2 oz
Leica Summarit-M 35mm f/2.4 ASPH (most lightweight Leica lens): 6.9 oz

Total: 28.1 oz

Olympus Pen-F: 15.1 oz
Olympus 12-40mm f/2.8 “PRO” lens: 13.5 oz

Total: 28.6 oz

So it’s about the same weight (less than half an ounce difference), but the advantage of the Olympus setup is that you can zoom from 12mm to 40mm (equivalent to 24mm to 80mm). With the Leica, you are stuck at one focal length. Plus with Olympus you get image stabilization for sharp landscape photos when the light becomes more dim. Image stabilization more than makes up for the Leica having a full-frame sensor.

I previously tested the Olympus 12-40mm lens and determined that it was as sharp as prime lenses, although sharpness is a bourgeois concept so maybe you shouldn’t care about that anyway. However, if you are going to be a sharpness Nazi, then you should probably get another brand of full-frame camera that has a high-resolution sensor of more than 40 megapixels. The Leica M (Typ 262) has only 24 MP, so if you are imagining making these huge 40 x 60″ prints, the Leica doesn’t have the resolution that you really need for that.

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If people were actually reading my blog and leaving comments I can imagine at least two types of angry comments.

1. You FOOL! The Leica is FULL FRAME! Any camera with less than FULL FRAME makes garbage photos! You MORON!

2. You FOOL! No lens is sharper than LEICA. NO LENS! You MORON!

Sorry, I don’t buy into either of these arguments. The real test would be to make some really big prints, one from photos taken with the Olympus setup, and one with the Leica setup, and do an experiment to find out if knowledgeable viewers can consistently identify that the Leica print is somehow superior without knowing in advance which cameras and lenses were used.

Olympus 12-40mm f/2.8 lens, review conclusion

12-40mm @ 12mm, demonstrating the value of wide angle when shooting in cities

I find this lens to be as good as advertised! Highly recommended.


  • Sharp corners, even at widest focal length where most lesser zooms have soft corners.
  • Sharp fully zoomed in, where most lesser zooms become softer.
  • Sharp when used wide open, at all focal lengths.
  • No purple fringing.
  • No field curvature (that I’ve noticed; I only tested for field curvature at the wide end).
  • Less expensive than buying a bunch of prime lenses. (This week, the 12-40mm is selling for the same price as just the 12mm f/2.0 by itself.)


  • Lateral chromatic aberration.
  • Lens blocks built-in pop-up flash on some Micro Four Thirds cameras.
  • Lens hood is cheaply made.
  • Big and heavy for a Micro Four Thirds lens (although quite a bit smaller and lighter than the comparable Canon 24-70mm f/4.0 full-frame lens).

What this lens is best at:

  • Event photography (I would expect that this is the number one lens for wedding photographers who shoot Olympus)
  • Landscape and cityscape
  • Travel photography (if you don’t mind the weight)
  • General purpose photography (the most versatile lens to have if you have no idea what you want to take pictures of)

What this lens is NOT best at:

  • Portraiture (generally you should use a prime lens for better bokeh, however the 12-40mm is excellent for a type of wide-angle portraiture where you don’t want a blurred background)
  • Street photography (too big to be inconspicuous)
  • Photos that have no purpose except to show off extreme bokeh (and there are lots of these types of photos on Flickr)
  • Any use that require focal lengths wider than 12mm or longer than 40mm

I have written a whole series of blog posts about this lens before writing this conclusion. Read the details:

G.A.S. attack (Olympus 12-40mm lens)
Olympus 12-40mm f/2.8 “PRO” lens, first impression
Olympus 12-40mm f/2.8 second impression: this lens is ginormous!
12-40mm F/2.8 vs. 17mm f/1.8 extreme corner(with test photos)
12-40mm f/2.8 vs. Ricoh GR (with test photos)
Olympus lens test: 12-40mm vs. 9-18mm extreme corner (with test photos)
Olympus 12-40mm f/2.8 vs. three primes (with test photos)