This is an incredibly underrated lens for wildlife and birding. I recently purchased it and have been out with it a few times. Yes, it is a little on the heavier side - I need to get used to the weight and balance difference from the 100-400mm v1 that I have been using. If I am not conscious of it, I tend to start drifting down with the lens as I am shooting, especially moving subjects. Image Stabilization works great for the reach you are getting with this lens. I am almost always hand holding when shooting local wildlife or birds. While the big white is no doubt a slight step above and worth every penny, it is just not really necessary to get great pro-level shots of birds and wildlife. If you need that level of performance, by all means go for it! If I had $8k burning a hole in my pocket, I'd add it to the stable :-) But do not feel that you HAVE to have it to take great pictures. Finally, do not be deterred by the noise about this being a Sigma lens. Sigma has been making great quality lenses for decades, and this is no exception. The M.Zuiko Digital ED 150-600mm F5.0-6.3 IS is NOT just a knock off of the Sigma Sport 150-600mm. It has significant improvements to suit and excel on the OM System m43 platform. It is worth the price premium over the Sigma version. Just a note for those with older camera bodies, I have confirmed that this lens works at least as far back as the E-M1 Mark II camera. Sync-IS may not be quite as good but it does seem to work based on the couple backyard shots I tried with that combo.

Coming from an older superzoom and having used large spotting scopes back in the day, I’ve really enjoyed what the 150–600 brings to the table. On Micro Four Thirds, having a 1200mm equivalent reach is amazing, it’s exactly the kind of distance I’ve always wanted (and believed necessary) for wildlife photography, even when I’m relatively close to the animals. I haven’t had tons of time with it yet, but the photos I’ve taken have impressed me with their crispness and reach. I sometimes wonder if I should’ve gone for one of the PRO lenses, but honestly, for my needs this one has been perfect. For what it offers, the weight is very manageable, at least for me. I paired it with a good strap and a monopod/tripod combo, but so far, I’ve shot almost everything handheld except for moon shots or nearby stationary subjects. The stabilization is ridiculously good. I even walked with it for a few hours the other day and didn’t find the weight to be an issue, considering the 1200mm equivalent reach, it’s lighter than I’d expect.

I find this to be an affordable, long reach telephoto lens. I often shoot birds with the 300mm and the 2x MC converter but I sometimes need a wider field of view - and sometimes the opportunity calls for a close-up view. The M.Zuiko Digital ED 150-600mm F5.0-6.3 IS is a perfect solution, albeit a bit heavy compared to other Zuiko lenses (but with the Cotton CCS G3 harness, this is no longer an issue). I find a certain softness at full reach but my shoots are not often at that distance. It focuses quickly with both the 1.4 and the 2.0 MC converters in all target modes but I normally stick to the 1.4 extender because with the 2.0 things become really hard to handle - despite the very good IS. All in all, I've made this my go-to lens for birding.

The M.Zuiko Digital ED 150-600mm F5.0-6.3 IS I have found to be an excellent lens to complement birding in the field. I use the lens with the OM-1 Mark II camera, almost always with bird AI option ON. Primary use is to capture images of birds for post-birding ID work, upload to eBird for citizen-science use, and for use in educational programs. I have used this lens extensively over the past year, mainly hand held, and have found the IS system to work incredibly well, definitely improving the capture of sharp images. The lens is hefty, and takes a steady stance, but I am 70 and can manage crisp images — bird AI and IS improve image capture tremendously. I use a hip carry system and when in the field for hours and traveling miles, lens and camera carry is not an issue. Focus is fast and reliable, a huge help with smaller songbirds that don't sit still, as well as for in flight birds, for which the AI tracking works amazingly well. The great reach of this lens is a true asset in the field, bringing high soaring birds into focus and providing for amazing detailed close ups of birds in the 50-foot a closer range. Based on many online reviews I was initially worried about weight of the lens and if that would be a detriment—some reviews suggested this lens should only be used with tripod or monopod. I disagree—this lens is an incredible bird photography asset, able to capture high detailed, close up images of both stationary and in-flight birds. I don't head out birding without this lens.