Panasonic LUMIX H-RSA100400 100-400mm

The Panasonic Leica 100-400mm is the sharpest, best-built telephoto you can slap on a Micro Four Thirds camera, scoring in the 89th percentile for optics. The f/6.3 aperture is a bright-light dealbreaker for some, and the hood is annoyingly fiddly, but if reach and image quality are your priorities, this is the lens to get. At around $1,700 from the right store, it's a serious tool for wildlife photographers who don't want to lug a full-frame rig.

Our database puts this lens's optical quality in the 89th percentile, and that checks out in the field — it's tack sharp even wide open at 400mm, with barely any falloff at the edges. Build quality is truly best-in-class (97th percentile), rivaling lenses costing twice as much. Stabilization is well above average, keeping things shake-free when you're handholding at ridiculous focal lengths. Autofocus is quick and accurate for stills, though it's firmly middle-of-the-pack; not a speed demon but perfectly fine for tracking birds. Bokeh is average, which is fine for a lens like this. The weak spot is macro — at 26th percentile, it's one of the worst we've seen for close-up work, so ignore the marketing claims if that matters to you.

This lens sits in a weird spot in the lineup because most of its listed competitors aren't direct rivals. The Canon RF 28-70mm f/2.8 and Viltrox 15mm f/1.7 are fast full-frame glass for totally different tasks, and the Nikon Z 18-140mm is a slower superzoom with half the reach. Against its real MFT competition, like the Olympus 100-400mm or the older Panasonic 100-300mm, the Leica absolutely wins on build and image quality. But if you need an f/2.8 aperture or plan to adapt to a full-frame body later, skip this and look at a Sigma or Tamron 150-600mm — you'll lose some portability, but gain light and flexibility.

Prices range from about $1,715 to $2,150 depending on where you shop, with Newegg offering the most affordable option. That's a big spread, so shop around. For the money, you're getting top-tier build and optics in an MFT mount, and if you're a dedicated wildlife photographer, it's absolutely worth it. But the value argument gets shaky if you compare it to full-frame alternatives that can be cheaper and faster. The Panasonic 100-300mm saves you a pile of cash and weight, though you'll sacrifice that premium Leica feel and some sharpness. If you need the absolute best MFT telephoto, this is it — just accept you're paying a premium for the privilege.

Panasonic's Leica DG Vario-Elmar 100-400mm f/4-6.3 II is basically a super-telephoto cannon for Micro Four Thirds, giving you an 800mm equivalent reach in a package that doesn't require a sherpa. The Leica badge isn't just for show either — the build quality is exceptional, with weather sealing, a tripod mount, and that reassuring heft that whispers premium. It's aimed squarely at wildlife shooters who want to pull distant subjects close without swapping to a full-frame monster.

That said, the f/6.3 aperture at the long end is a compromise, and at nearly a kilogram it's not exactly a pocket lens. But for MFT users who need serious glass for birding or travel, this one punches way above its weight class optically. Just know you'll be trading light-gathering for portability compared to bigger sensor systems.

Skip this lens if you frequently shoot in dim forests or at dawn — the f/6.3 aperture will force you to crank ISO or lug a tripod, and there are cheaper, faster full-frame options that do better in low light. If you're on a strict budget and just want to try wildlife photography, grab the Panasonic 100-300mm instead; it's far lighter on your wallet and your neck, even though you'll lose the premium build and ultimate sharpness.

Birders, wildlife junkies, and anyone with a Micro Four Thirds kit who needs an 800mm equivalent with zero excuses on sharpness should buy this lens. It's the best super-telephoto available for the system, period. Just plan your shoots for daylight or carry a good tripod because that slow aperture means dusk and dawn hunters will feel the pain. If you can stomach the price and hood quirks, it's a long-term investment that will deliver stunning results.