Panasonic Leica DG Vario-Elmar H-RSA100400 400mm

The Panasonic Leica 100-400mm is a razor-sharp, beautifully built super-telephoto that gives MFT shooters an 800mm equivalent reach in a portable package. Optical quality is outstanding, but the slow f/6.3 aperture means it's a fair-weather friend. Buy it for lightweight wildlife trips, skip it if you often shoot in dim light or are on a tight budget.

Sharpness is the headliner here. It's crisp across the frame, even at 400mm, which puts it in the top tier of lenses we've tested optically. The autofocus is fast and accurate for tracking birds or planes, though it's just middle of the pack compared to newer linear motor designs. The stabilization is strong, letting you handhold at crazy focal lengths in decent light. The weak spot is the aperture. At f/6.3 on the long end, this thing gets dark fast, so you'll be cranking ISO when the sun dips. Macro performance is also a letdown, landing near the bottom of our database despite the 0.5x magnification claim.

The Sigma Contemporary 16-300mm is a more versatile all-in-one option if you don't need the extreme 800mm equivalent reach, but it can't touch the Panasonic's build or sharpness at the long end. The Tamron 18-300mm is lighter and cheaper, but again, you sacrifice that extra 100mm of reach and the premium optical quality. On the full-frame side, a Sony 200-600mm paired with a high-res body gives you cropping flexibility and better low-light performance for a similar price, which is why some users feel this Panasonic is overpriced. This lens wins when you prioritize a lightweight MFT kit for hiking or travel where every gram counts.

Pricing is a bit of a rollercoaster, with a $333 spread across vendors. You'll find the best deal at Newegg, but even then, you're dropping serious cash for a Micro Four Thirds lens. The value argument hinges on whether you need this specific reach in a portable package. For a pro-level Leica-branded optic with this build quality, it's a fair price. But if you're just dabbling in wildlife, the cost stings, especially when full-frame 150-600mm lenses can be had for less.

Panasonic teamed up with Leica to build this 100-400mm zoom, and it shows. You're getting a 200-800mm equivalent reach on Micro Four Thirds, which is absurdly long for a lens that weighs under a kilogram. The build quality is top-tier, it's weather sealed, and the optical stabilization actually works. It's aimed squarely at wildlife shooters who want to travel light without sacrificing reach.

If you primarily shoot in forests, at dusk, or anywhere with less-than-ideal light, look elsewhere. The slow aperture will frustrate you with noisy high-ISO images. Also, if you're not already invested in the Micro Four Thirds system, a full-frame body with a 150-600mm lens can give you similar reach with better low-light performance for the same money.

This is a specialist's lens. If you're a Micro Four Thirds shooter who lives for wildlife, birds, or airshows and wants to keep your kit light, this is the best long zoom you can buy for the system. The optical quality and build are genuinely impressive. Just know that you're trading low-light performance for that portability, and you'll need to budget for the steep price of entry.