Subscribe to see EXIF info for this image (if available) Background Sometimes you just fall into some good deals and that is what we found here. A used copy of the Panasonic 12-35 was available when I picked up a gently used Olympus EM5 Mark 2. I originally had an Olympus 12-40/2.8 so I will not only show sample images from the Panasonic, but I will do some comparisons between the two. Handling/Size/Weight When you think about this lens and its equivalent field of view of something like a Nikon FX 24-70 lens, this thing is absolutely tiny! Subscribe to see EXIF info for this image (if available) ©camerasize.com Nikon D700 w/ 24-70/2.8 and Olympus EM5.2 w/ Panasonic 12-35/2.8 One of the differences between the Olympus 12-40/2.8 and this lens is the material that covers the lens. Living in an area where the winters here can be quite brutal, having a barrier between your ungloved hand and the metal of a camera lens is often a welcome thing. The Olympus is an all metal construction, even the zoom/focus rings are metal. Panasonic went with a rubbery material around the rings. This will be a great benefit to me in those cold shooting months. Focusing rings are different between the Olympus and the Panasonic lenses as well. The Olympus has a manual override clutch system (which I prefer). The Panasonic, you must select manual focus or the AF+MF mode within the camera body. The focus ring on the Panasonic is well dampened and smooth for those that might have need to use it. The only switch on the lens is the Power OIS switch. I leave this on OFF as I allow the fantastic Olympus IBIS (in body image stabilization) to handle my stabilization needs. Subscribe to see EXIF info for this image (if available) 1/500, f/4, ISO 200 The lens is weather sealed as well, so has protection against water, snow, dust and extremes of temperature. Always remember, though that weather sealing is a an all or nothing concept. Weather sealing is only at its most beneficial when you have both a weather sealed camera body as well. The EM5.2 is indeed weather sealed, so makes for a good pairing. Subscribe to see EXIF info for this image (if available) 1/4000, f/2.8, ISO 200 The Panasonic is 5mm focal length shorter than the Olympus. In practice, I never notice this difference. I find that I would notice more of a difference on the wider end than the longer. For example, I can tell a big field of view disparity between 12mm and 14mm. Image Quality I cannot honestly see much of a difference between the images I get from this lens against the Olympus equivalent in regards to sharpness. Straight out of camera, I might give a slight advantage in contrast to the Panasonic. However, any differences can be made up for if you have a good grasp of your post processing. Subscribe to see EXIF info for this image (if available) 1/1600, f/4, ISO 200 One thing to note as a "negative" on the Panasonic. On the EM5.2, I have issues with all Panasonic lenses of the shutter shock variety. I've had issues with all these lenses that I've owned and reviewed: 14/2.5, 12-32/3.5-5.6, and the soon to be reviewed 35-100/2.8. The 12-35/2.8 is no different. I would ensure that any Olympus camera you choose to use this lens on should have an anti-shock mode. Focusing Auto focusing is fast and accurate, as you would expect from a micro four thirds camera and lens of this caliber. I noticed no hunting or missed focus issues. Subscribe to see EXIF info for this image (if available) 1/500, f/4, ISO 200 Against the Olympus - while I do not have both to test head to head, I can't imagine if one were faster than the other it is most likely negligible. In use, I never had an issue with AF speed with either lens - so fast to the point that if it couldn't have locked on in time, I probably would have missed the shot anyway. Bottom Line Brand new, the pro line m43 lenses are an expensive proposition if you look at them against the other lenses in the m43 lineup. However, if you look at them against other systems - even brand new they are a bargain. A new Nikon 24-70/2.8 VR lens will run you $2400USD, where are the Oly/Panny field of view equivalents are under $1000 new! I was able to pick up this Panasonic lens used for $480! You are not going to touch even a used 24-70 non-VR lens for that price! If you look at other head to head reviews on the Panasonic/Olympus 12-40 range lenses, you'll see that most people couldn't really give one an advantage over the other from a purely "lens only" view. However, if you look at the other traits, it might make the decision fall more to one over the other. If you have an m43 camera with no IBIS, then the Panny makes sense. If you do a lot of manual focusing but don't like to have your camera in AF+MF mode, then the Oly makes more sense. Shutter shock is a reality on the Olympus EM5.2 for the 12-35, so keep in mind that used on an Olympus body - ensure that you haev anti-shock enabled! That's really the only differences that have any real meaning. So, if you are on the fence on which to get, don't worry about AF speed or image quality. Consider them equal for all intents and purposes.