I sold my 7-14 Pro and bought the PL 8-18 instead for the weight reason. I found I was not taking it with me very often because of the size and weight. So far I am very happy with the decision. There is no denying that the 7-14 takes excellent images but the PL 8-18 does as well. I’ve presented crops taken from the f4 versions of both below, and it’s clear the Lumix G 7-14mm sample is exhibiting the infamous flare artefacts while the Olympus 7-14mm avoids them.

Chromatic abberations seems to be corrected well and so is the vignetting (but not the distortion). It seems that Olympus moved away from: "correct everything electronically" and now corrects a bit more optically (to the cost of size). We’ve become used to seeing excellent lenses from Olympus over the years, with both the 12-40mm f/2.8 and 40-150mm f/2.8 delivering exemplary results. But wideangle lenses are infamously more difficult to design, and this shows up when we examine images from the 7-14mm. That’s not to say that the lens is bad, but typically for its type, it doesn’t deliver quite the same corner-to-corner sharpness as its siblings. When zoomed in at 14mm, it becomes even better and you can really see how versatile this lens is. It is a characteristic that Olympus has implemented on all its Pro lenses. They all have very close focusing capabilities that remain constant throughout the entire zoom range. It is one of my favourite characteristics for sure. E-M5 II, 1/400, f/ 5.6, ISO 200 – 14mm E-M5 II, 1/400, f/ 5.6, ISO 200 – 14mm – Crop

Finally, if, (and it's a big if, because they don't appear very often!) you see the old version for sale at a decent price secondhand, and it's weight and bulk aren't an issue, I'd say definitely go for it, as I can certainly confirm that it's one hell of a performer, and you'll be hard-pressed to see much of a difference, even when pixel-peeping. With the Olympus M.ZUIKO Digital ED 7-14mm f/2.8 PRO wide open at f/2.8, you can see some noticeable light fall-off in the corners. Stopping down helps, although to completely get rid of this phenomenon, you will need to use an f-stop of f/5.6 or smaller. There's also mild barrel distortion apparent at 7mm.

I realise this is not a complete comparison but it does give you a good idea of the differences between these two wide angle lenses.

Overall, the lens isn't particularly large, measuring just 4.2" (105.8mm) in length and 3.1" (78.9mm) in diameter. Weight is just over a pound at 18.8 ounces (534g). Another interesting characteristic of this lens is the minimum focus distance of 7.5cm (measured from the sensor) that remains constant throughout the entire zoom range and gives you excellent macro capabilities. Of course we aren’t anywhere near a 1:1 ratio but the lens can focus close enough to capture interesting details or to create original compositions. The sharpness remains fine at close distances even at f/2.8. Once again the story remains the same at all aperture values. Closing the aperture on the Lumix lens sadly won’t fix this issue, so bonus points go to Olympus here, although as you’ll also see, they both look similarly sharp in the crop below. I’ve also looked-out for flare across the focal range of the Olympus and not found any yet, apart from when pointing directly at the Sun. The Lumix 7-14mm has a lighter construction (metal and plastic) and is not weather-sealed. Its size makes it more suitable for small Micro Four Thirds cameras including the Olympus Pen series or the Lumix GM series. The Olympus 7-14mm f2.8 isn’t however the only ultra-wide zoom available for the Micro Four Thirds format. Early in the Micro Four Thirds story, Panasonic launched the Lumix G 7-14mm f4, a lens which shares the same coverage as the new Olympus, albeit with a constant focal ration that’s one stop slower. I own this lens, so was keen to see how it compares against the new Olympus and you can find out as my review-in-progress unfolds! Note Olympus also produced a 7-14mm f4 lens for its earlier Four Thirds DSLR system which can be adapted for Micro Four Thirds use, but the M Zuiko Digital is smaller, lighter, optically brighter and most importantly, native to Micro Four Thirds. Find out if it’s the ultra-wide lens for you!