"The only way to get to know a lens is to use it for a year.
Lens tests are just shortcuts."
—Unnamed Leica designer; quote could be apocryphal.
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Here's the lens under discussion:

The Olympus 17mm ƒ/1.8. That's the B&H Photo link. Here it is from Amazon, and from Amazon UK, and here are our other links.
Here's what our readers who use this lens think of it:
[Pace Luke in the Comments section, note that the illustrations are merely to show what people use the lens for, not to provide evidence or proof of its technical optical properties. —Ed.]
Photo by Matti Sulanto
Matti Sulanto: "I got the lens because it is small, fast and it has just about my favourite angle of view. At the time it was also the only choice with AF.
"I use the 17mm when I need a small lens on my Olympus. It is also very simple and not very exciting, but I like that, and it never interferes with my shooting. Optically it is better than its reputation and I have shot many presentable photos with it. I use it mostly for street shooting or similar and most of the time the aperture is set around ƒ/4–5.6, but the relatively bright ƒ/1.8 maximum aperture makes it also really handy after-dark lens, especially with the excellent IBIS of Olympus."
Howard: "I love the lens. I use it on an E-M1. 35mm-equivalent is my favorite focal length. It's small and light. I prefer it to the 20mm Panasonic because I prefer the Olympus rendering and the autofocus is miles faster and quieter. Though I've read it's not as sharp as other options in this focal length—including the 12–40mm Olympus ƒ/2.8 zoom at 35mm-e, which I also own, or the Panasonic 20mm prime which I also own—I have never noticed lack of sharpness to be a problem—and I pixel peep.
"I'd prefer that it were ƒ/1.4, but then it would probably be quite a bit larger and would have other tradeoffs."
Rev. Heng Sure: "With the Olympus 17mm ƒ/1.8 Mounted on my Pen E-P5 I enter my Cartier-Bresson fantasy; I imagine my camera invisible while I merge into the background, capturing decisive moments."
Marc Gibeault: "One thing about this lens stand out for me: its price. I got it from Olympus Canada for CAN$349. So, along with the 45mm ƒ/1.8 and the 25mm ƒ/1.8 [both US$399 —Ed.], I have a trio of primes I wouldn't be able to get from any other system. There's no way I could rationalize more than $1,500 in lenses for one of my numerous hobbies...and the quality, as we'll see in the samples shown here, has nothing to be ashamed of."

Photo by Ståle Prestøy
Ståle Prestøy: "I'm a zoom user and have the M.Zuiko 12–40mm ƒ/2.8 and 40–150mm ƒ/2.8 PROs, which is more than sufficient focal range for me. But I've always wanted to find a decent, normal prime lens for stay-on lens for almost any casual photography.
"I've used 50mm-equivalent lenses both on film and digital cameras, but I never came to a point where this focal length became natural to me. Although I was very happy with bokeh and sharpness the field of view was too narrow and restricting. I also tried the 28mm focal length, and I've got much fun and nice memories from using it. But it soon became clear that it wasn't as versatile as I would have wanted. The wide angle characteristics became too restricting for me, so it too spent most of its time as a dust-gatherer on the shelf.
"Last year I found that it was time for taking a step up from 28mm and bought a 35mm-e in the shape of the M.Zuiko 17mm ƒ/1.8 (...OK, 34mm then ;-) ). I've been using this lens for some months now, mainly on an E-M10 but lately also with an E-M1.
"When some scene catches my eye and I look at it through the viewfinder and this lens, it feels very close to how it seemed like 'in real life.' Looking at the world through it feels like a normal framing for my eyesight—and that's the beauty of the lens for me. Of course, the fact that it's got great sharpness and a wide aperture, is light and small, affordable, and a dream to handle also counts. And with this lens I seem to use manual focusing more frequent than autofocus. It's a no-hassle lens, really.
"So, at last I can say that I've found my normal lens! From now on there will always be a 35mm equivalent at hand, either on the camera or in my camera bag.
"I found this review helpful when deciding to go for this lens."
Frank (partial comment): "I'm not really qualified to judge its optical qualities, but the physicality of the lens makes me want to use it. [...] One optical negative that I've noticed is that taking pictures of neon signs at night really leaves a pronounced ghost. It happens somewhat with other lenses too, though.
For the complete text of partial comments, please see the Comments section. —Ed.
Harold Merklinger: "I have never used this lens, or even seen one, but I think I can still make a useful observation. The lens seems to be lacking a distance scale. There is a decorative depth-of-field scale, but no distance scale with which to use it. I looked at two other photos of this lens model on the internet. One showed a distance scale of somewhat limited scope: the only distance marks were 2, 5, and infinity. The other had no distance scale, but at least had a place for one—unlike the lens in your picture. [The focus ring snaps up and back to shift from manual focus to AF, which accounts for the apparent contradiction in appearance —Ed.] The depth of field scale itself appears to be an 'artist's depiction.' The aperture marks are not spaced quite correctly relative to one another. Mind you, that can be said of some real [i.e., manual —Ed.] lenses I've seen too."
[Old friend Harold retired in 2001 as Director-General of the Defence Research Establishment Atlantic (Canada) in Dartmouth, Nova Scotia, where he specialized in sonar research for the Canadian Navy and Air Force. He authored a pioneering article about bokeh in 1997. Several of his excellent photo-tech books are available for download here. —Ed.]
Eric Erickson: "I really do like the lens, and find myself using this lens and the Leica Summilux 25mm the most. I have all the zooms for the Olympus E-M1 but when traveling I like to stick to one lens, generally a prime. The images this lens produces are sharp and the color rendition is perfect.
Photo by Eric Erickson
"This image is a simple street shot from Paris I took last Fall. I had with me only this lens and the camera. It is a very liberating experience to travel with one camera and one lens. I do not have to think about which focal length to use, or whether I need to zoom; I don't have to think about changing the lens and putting something else on the front of the camera, because that is all I am carrying.
"When I travel, we are on and off planes, trains, buses and cars. I do not work from my trunk like a lot of photographers, so whatever equipment I need for the day is with me all day. This is why I continue to travel with the Olympus and several small lenses. I do have a big old Nikon D800 sitting in my closet gathering dust. I like the full frame sensor, and I keep it and the assorted lenses thinking that maybe, just maybe, Nikon will introduce a mirrorless camera at some point. However it does not seem to be happening. Until then, I will use this little gem of a lens and the Olympus E-M1."
Bruce Bodine: "Robin Wong has several photos and comments about the lens and yes I know he is now an Olympus employee. I have found it to be an excellent companion on my EM-1 for those low light interior photos."
Nicholas Dunning (partial comment): "I owned the 17mm for a while and the short summary I could give of it is that it is a good all-round lens that does a lot of things well but nothing great."
Karl: "Love this lens! I'll be starting my one year challenge in the next week or so and it will be what I use.
Catch of the Day
Sunset Pier
"Small, light, fast to focus—isn't this the attraction of Micro 4/3 to begin with? I really like how the front element doesn't extend, all focusing is internal. Implies some sort of sealing [Internal focusing often means less dust incursion, but the 17mm is not weather-sealed. —Ed.]. Plus I can put it right up against glass and not have the camera move a bit when it locks focus."
Carl: "I got one of these about five months ago, and it immediately became my most-used lens for digital capture. The focal length is just right for me, it handles and balances great on a Lumix GX7. It has a special 'look' to the images that I won't try to describe technically but I'll just say I like it.
"I'll try inserting a link to this morning's post at my blog, which, like a majority of posts there over the past months, was made with this lens."
JK: "I’ve already written about this lens for TOP (here) but I’ll add just a bit. There’s something smooth yet sharp to its rendering that I find totally addictive. It reminds me of the old 35mm Summicron, or that lovely lens on the original Konica Hexar. In any case it spends a lot more time on my camera than this 50mm shooter would have ever imagined. Recent example here.
"By current Micro 4/3 lens standards, the Panasonic 20mm is a bit pokey to focus in good light, but it's no deal breaker. The real problem is in lower light, where focus slows to a crawl, hunts, and sometimes fails altogether."
Photo by sneye
sneye: "I've been using the Olympus 17mm ƒ/1.8 for almost two years. I have mixed feelings about it. In physical terms it is excellent: small, light, metal-clad and solid. Love the manual-focus mechanism with its distance scale, which makes it street ready. Optically, I've seen sharper glass (especially for distant subjects). It also suffers from the dreaded 'shutter shock' more than other lenses I use, but there are ways to avoid issues.
"Importantly for me, it has a very fine micro contrast which makes it highly suitable to monochrome. I would not recommend it for landscape or architecture photography, but it's more than adequate for human subjects and their environment."
Ash: "The 17mm ƒ/1.8!
"I used this lens heavily for two years, and it hit all of the right buttons. Sharp, small, fast autofocus, classic focal length, nice build quality. Combine it with the Olympus 45mm ƒ/1.8 for a great two-lens combo.
"If you enjoy shooting the 35mm view, then this lens deserves your consideration.
"It is good for family:
"Good for streets and travel: 
"And handles flare in a very pleasing manner, especially when used wide open at night." 
Photos by Ash
Rod Thompson: "I have a real love/hate relationship with this lens. In a recent comparison with the brilliant 23mm Fuji (on an X-E1), I duplicated a morning's mixed pictures with the two (RAW with the Olympus and JPEG with the Fuji) and printed them (on a Canon Pixma PRO9000 Mark II).
"At 11x14 size, I could not split them! The Olympus system usually won on accuracy of focus and had the added depth-of-field benefit; the Fuji lens was on close inspection the sharper optic, but this was lost in the prints. I have had and am looking at getting again the Panasonic 20mm for the added 'snap,' but the Olympus is still my choice for fast street shooting.
"I must admit to having regular crisis of confidence regarding the lens, but it constantly stands up to comparison. It is not super sharp first shot, but sharpens well as long as the photo is not murky and noisy, where noise reduction can make sharpening a real tug of war. With plenty of contrast and good exposure, it goes well.
"Ming Thein has a good review, Steve Huff also. It is a real test of sufficiency in optics balanced against a great handling experience. I had to agree with 'A Little Lens Tale' on this blog as I have owned both of the noted lenses (the 28mm Canon and the 17mm Olympus)."
Eamon Hickey: "When I did the 'shooter's report' for Imaging Resource's review of the Olympus E-P5, the camera came with the 17mm ƒ/1.8. There's a plethora of my pictures and a short-ish write-up in the IR review and in the gallery associated with it (scroll down to the shooter's report section).
"Executive summary: I really liked it for street and travel shooting. Very compact but well-built. Love the 'snap focus' feature. It exhibits some distortion, chromatic aberration, and 'bokeh fringing,' but I personally really liked its rendering quality, which I would call smooth, for lack of a smarter observation.
"Imaging-Resource also did a formal set of tests of the lens, and there's a link to that test in the review I mentioned above.
"Here's a picture of a New York City summer evening that I liked but IR didn't see fit to publish:

Photo by Eamon Hickey
Alan Ross: "The Micro 4/3 forum has a thread of sample images from each of the Micro 4/3 lenses. The one for the Olympus 17mm ƒ/1.8 is here. I'm shopping for a 'normalish' prime lens, so will be interested in the feedback you get."

Photo by Dori
Dori: "This is a photograph I took in Venice, Italy, at night. I love how well the E-P5 and the 17mm worked in such low light. The colors are great."
Ctein: "I find that Photozone's reviews come closest to my experiences with (and tests of) lenses.I find them especially valuable when I'm comparing across lenses where I already own one of the lenses they've reviewed. They're my go-to place. Also, their sample photos actually tend to be useful! Wonder of wonders. Here's their review of the 17mm."
Andre T. Nygen: "I used mine for about a year but replaced it with the Panasonic/Leica 15mm which is much sharper wide open; an important factor for me since I shoot portraits and require that narrow depth-of-field so very precious to Micro 4/3 shooters. Comparing prints by looking at individual eyelashes of my subjects, I find the Leica-branded lens to be superior in terms of sharpness. When stopped down, they are both very similar."
David Littlejohn: "This is the lens I use to document my life. Mounted on a Panasonic GF6, it is generally in my jacket pocket or in my hand when I leave the house. It gets used mostly in social situations: holidays, parties, vacations, hanging out. Inside, I shoot it wide open to one stop down. I find that it's usually better to shoot wide open and get a higher shutter speed. When conditions are good, I shoot it at ƒ/4.
"I have to turn on Remove Chromatic Aberration in LR. And I sometimes lighten up the corners a bit to counteract vignetting. Other than that, the lens is trouble-free and makes very nice pictures."
Alan: "I'll throw in my two cents. This is my most-used Micro 4/3 lens, which is a secondary system for me. It has a relatively sharp center, has good color, bokeh, and flare control. Its relatively compact, focuses fast, and is light weight.
"However, it is bigger and more expensive than the Panasonic 20mm 1.7, its finish wears pretty easily (especially on the focus ring), and has a fair bit of software correction (particularly distortion and vignetting). That means softer and noisier edges.
"I use it on an E-PL5 mostly, as a lightweight, fast, compact setup. I think the 20mm 1.7 is a better lens optically (not to mention I love its size) but the autofocus is miles better on the Olympus. I have not tried the Panasonic 15mm ƒ/1.7 but looks around the same size, and is more expensive. I do not find I use the focus clutch much, as I find its autofocus pretty reliable. Its important on this system to be compact, fast focusing, light weight, and relatively inexpensive. This lens checks all those boxes.

Bigger here

Bigger here
Jayson Merryfield: "About me: I shoot people mostly, and am a part-time professional wedding and portrait photographer who has been shooting with Olympus gear for a few years now, starting in 2009. Last spring I bought an E-M1 and picked up this lens at the same time, and it remains my only native Micro 4/3 lens. I convert the rest of my lens collection to the E-M1 via convertor, which works well enough for me at this point.

Photo by Jayson Merryfield
"About the lens: the number one thing that leaps out to me (and anyone else I show it to) is just how preposterously small it is, particularly compared to the full frame equivalents that my industry peers here use. Almost any body that it’ll pair with is small enough to be notable, but the sheer difference in lens size borders on incredible.
"Image quality wise, I am not a great reviewer, as I have limited experience with other brands. After shooting for a year with this lens, nothing stands out as a negative in this area. Focus is quick and accurate in good light and in bad. Detail and sharpness is more than adequate without being overmuch, and in particular I find this lens is very friendly with faces and people in general.
"Honestly, I have a lot of difficulty separating the overall image quality of this lens from my excitement in having a fast, slightly wide lens from Olympus. Being able to get any amount of background separation when shooting wide has been a want of mine for years, and I’m finally able to get it. Plus, I’m finding that 35mm-e is just a wonderful focal length for environmental portraiture."

Photo by Andrei Kozlov
Andrei Kozlov: "To me this 17mm is a perfect vacation lens. It has very natural field of view: large enough, but not too wide to cause distortions. Additional bonus: when 'developing' RAWs in Capture One, you get quite a bit of extra, perfect for situations when you'd wanted it just a little bit wider....
"Here is an example set—spring break vacation with our son that was shot mostly with 17mm. (I am building my personal time machine with these photos, and 35mm equivalent field of view is just perfect for it.)"
And the last word from...
Gordon Lewis: "I shot this photo while testing the Olympus EP-5 (Part I, Part II) with 17mm ƒ/1.8 Zuiko for TOP. What impresses me most about this lens is that I could get so much depth-of-field and center-to-edge sharpness at ƒ/4.5 and so little veiling glare, even with heavy backlighting. The tonality of the sheen on the water is amazing, as is the amount of detail in the vegetation. Its ability to render a demanding scene like this so well tells me more than any lines-per-millimeter or MTF chart ever could."
I hope you enjoyed this variety of opinions from many users. I want to thank everyone who commented and who sent me pictures, especially the pictures I was not able to use—I received far more than I could publish. Thanks to all.
Here again is the B&H Photo link. Here is the 17mm ƒ/1.8 from Amazon, and from Amazon UK, and here are our other links.
Mike
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