The Olympus M.Zuiko Digital ED 12-40mm f2.8 PRO lens lives up to its moniker, delivering professional results when paired with a Micro Four Thirds camera.

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  Maximum f/2.8 aperture throughout zoom range. Very sharp from edge to edge. Focus clutch system. Protected from dust, splashes, and cold temperatures. Minimal distortion.

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  Expensive. Lacks optical image stabilization.

This standard zoom lens for Micro Four Thirds (MFT) system cameras provides an angle of view equivalent to a 24-80mm lens used on a 35mm format camera and sports a constant f/2.8 maximum aperture throughout the zoom range.

Those looking for a professional specified standard lens for their Micro Four Thirds camera are now spoilt for choice with offerings from Panasonic, and this lens from Olympus. This lens delivers outstanding sharpness through much of the zoom range at maximum aperture and sports a robust, dust and...

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  Outstanding sharpness from maximum aperture, Compact and lightweight, Robust build, Dust and splash proof, Quick access for manual focus, Good value

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  Manual focus control easily nudged when changing lenses, Heavily affected by diffraction at small aperture settings

The Panasonic G X VARIO 12–35 mm f/2.8 ASPH. P.O.I.S set the standards pretty high in this category but the Olympus company managed to meet them without any problem. First of all they produced a bit cheaper lens with a wider focal range.

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  solid casing, mostly made of metal,, excellent image quality in the frame centre,, very good image quality on the edge of the frame,, very good correction of chromatic aberration,, moderate astigmatism,, splendid, fast and silent autofocus,, sensible performance against bright light.

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  huge distortion at the wide angle of view,, distinct coma at the maximum focal length,, noticeable vignetting at the shortest focal length.

The 12-40mm f/2.8 lens is an impressive performer, delivering quality that rivals that of many DSLR+fast zoom pairings that target serious enthusiast photographers. But its great advantage is being able to do this in a more compact, lighter-weight unit.

I have been a long-time Nikon user and fan. I purchased this sense in conjunction with the OMD-EM1. I would put this up against anything on the market in thfull-frame arena! It is that good. I shot a number of photos where I would traditionally use a flash.

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  Quality buildWeather resistantImage qualityPro quality at a fair price

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  None

This is the ultimate lens if you're using an Olympus Micro 4/3 camera. Great range, from nearly-funhouse-wide to slightly tele, and absolutely razor sharp. Once you put it on the camera, you'll never want to take it off! But do, because every once in a while the Panasonic 20/1.7 needs some exercise.

After shooting with this lens and my PEN F setup I'm impressed and this coming from FF Nikon D5 user I went for the "lighter" for vacations but I find myself picking it up for shoots at time I'm hooked

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  How many times can I say sharp, fast focusing, versatile lens

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  Haven't found cons

I like this lens as my walk around lens. It is light and fun to use. Great package with the E-M1. Optically it is mostly good apart from the issue with ghosting and flares.

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  - perfect size and weight for my E-M1 - sharp (I have never noticed the tested weakness in resolution at 40mm in real world) - fast AF - water resistant (after about one hour in moderate rain and humidity at about 100% the lens became foggy from the inside and after half an hour in my bag it was ok...

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  Work with bright light sources in the frame. If you have bright light sources in the frame (e.g. candles at night) they cause annoying ghosting and flares. I hate this this behavior in the dark. In daylight it is usually acceptable.

This lens has been living on my E-M1 for several months. I still love primes, but it's hard to argue with the convenience and performance of this stellar zoom lens. It's my go-to lens for shooting events where I have to move and compose quickly.

This lens is wonderful well worth the money spent. It is a very good all around lens. Weather sealed and well built.

Of the 3 lenses this is my go to lens and stays on the camera most of the time. So versatile. It will shoot from wide angle to telephoto and gives amazing macro and low light results while the picture quality stays razor sharp the whole time. Worth every penny if you are serious about photography.

I am incredibly pleased with this lens. Zoom is shorter than what I am used to, but that will make me a better photographer I think, and it will get me to move more to/from my subjects (that's actually a good thing). The build quality actually surprised me.

Magnificent lens. Takes great shots and is very solid. It weighs a fair bit but provides results that make it worth it. Weather sealing is excellent, I've had it covered in rain and snow and never had any issues.

This is a great Lens. I should have bought it a year ago along with the camera as opposed to now. Any one who has made up their mind regarding the micro 4/3 system should juts get this lens.