PanasonicLUMIX G LEICA DG VARIO-ELMAR PROFESSIONAL LENS, 100-400MM, F4.0-6.3 ASPH., MIRRORLESS MICRO FOUR THIRDS, POWER OPTICAL I.S., H-RS100400 (USA BLACK)

I had been skeptical of the hype around this lens but I have to admit that the Panasonic Leica 100-400, is a fantastic buy. The photos that I have included are some of my early test shots at the local zoo. This lens will get used a lot.Best features:1. Small size. Anything close in angle of view for APS-C or Full Frame would be 2 to 3 times bigger and heavier. I am more likely to take this with me.2. Sharpness. This is as good if not better than any Nikon lens I have used and it is sharp at all focal lengths. Excellent contrast, too.3. The image stabilization of the lens/camera combination is nothing short of amazing. Handheld shots taken at 1/200 sec. that you can pixel peep are beyond belief.My only concerns so far are:1. The supposedly weak lens mount so I am being sure to hold it at the mid point at the tripod collar. I remove the extra tripod foot when hand-holding.2. It is not a fast lens at the 400mm length. Even at ISO 800 with the dual stabilization (which really works well), you are pushing the limits of handheld photography. ISO 1200 or higher is required with anything other than bright daylight or if the subject is moving.3. Learning the correct autofocus settings is still a challenge. In most situations, it is fast and accurate. I have a G85 with all the firmware updates but it is still tricky to find the subject if it is a small portion of the image. I might need to use the manual/auto focus combination setting just to get it started in the correct range or play with the focus area settings.

I've been a stock photographer for nearly nine years and recently switched from a full frame DSLR to the 4/3 format. Weight reduction was the driving force behind that decision but after using my OMD em 5II camera for over a year, the most positive change (improvement) is the ability to see the effect of your exposure, before pushing the shutter. Every shot can now be perfectly exposed no matter how difficult the lighting situation.My decision to buy the Panasonic 100-400mm Zoom Lens over the other purchase options has also exceeded my expectations. The zoom range is the most apparent improvement but it's not what make this lens such a great choice. Unlike most zoom lenses which are less than tack sharp at the extremes of their zoom range, this lens is super sharp all the way out to 400mm (800mm equivalent). It doesn't matter if you're using it to photograph an up close dragonfly or a distant bird your photograph will be sharp (assuming you've made the correct exposure decisions).The image stabilization is excellent as is the focusing which is extremely fast and accurate. I've even been able to do hand held focus stacking (thanks to Olympus Technology), with very good results (see attached dragonfly photo). As stated by other reviewers, the zoom is rather stiff but not unlike other professional lenses and is very acceptable in my opinion. Due to the limitations of the current focusing technology in 4/3 format this lens will not keep up with fast action like flying birds but then this is no surprise as I've had like results using my other lenses.While I have never given a five star rating before, I highly recommend this lens to anyone who wants "near perfection" in an extreme zoom lens. Without a doubt this lens has exceeded my expectations and is worth 5 stars and it's rather exorbitant price tag.

It was no surprise that this lens proves to be notably heavy, compared to my other m4/3 lenses. I obtained a monopod that has fold down legs and a tripod head to make it easy to hold the lens steady (I have a GH3 which doesn't have dual stablization like the latest Panasonic cameras.) The monopod further added plenty of weight. Once I get a decent strap for lugging the camera with the lens and monopod, it should be easier to use.The lens has a zoom lock mechanism to prevent the lens from extending under its own weight and it has a focus limiter to speed up auto focus. Too bad I forgot I had it turned on when I wanted to focus closer! The lens has a rotating tripod fitting and a tripod fitting extender mount for situations where there isn't enough clearance between camera and tripod to allow connection. Since the lens is weather sealed it works well with my GH3 in hostile environments like the beach.So far I've used it to photograph birds like sandpipers, willets, and egrets and it has done well. One minor quibble: the lens cap does not stay on as reliably as I would like and the lens barrel is too large for lens cap tethers, so I had to attach the tether with a narrow velcro strap. I will see how well that works with my next outing.

I was concerned with this purchase as the early indications from photog review sites showed the lens was not sharp. Panasonic & Leica seemed to recognize this and held up release of the lens to make appropriate adjustments. Knowing this & seeing a late "and very positive" review after it was finally released I took a chance and ordered it once it became available.Thank goodness I did that because this is a wonderful addition to our lens collection! Its a beautiful lens and works flawlessly but all that wont matter for me if its not sharp. Trust me this lens is VERY sharp and the colors are gorgeous!The thing I see about this lens is it needs to be worked to its strengths. Its obviously not the fastest lens in the world especially at the long end so you need to have good light in order to get the best results out of it. If I have poor, dim, overcast condition light I'm going to use my Olympus 40-150mm F2.8 Pro or 300mm F4.0 Pro lenses because they are a lot faster "although without the range on one or the zoom on the other". If I have good light this is the lens I will have mounted because its so versatile with that huge zoom range and is fully capable of producing stunning results!