Samyang SY24M-O

A screaming fast f/1.4 prime that delivers dreamy bokeh for a song, but you'll need to stop down to f/2.0 for pixel-peeping sharpness and fully commit to manual focus. If you shoot stars on a budget, grab the $549 deal and don't look back.

What surprised us most is how much sharper it gets just half a stop down. At f/1.4, stars look like little fuzzy blobs in the corners. Dial it to f/2.0 and they snap into tiny pinpoints. The manual focus ring is smooth and well-damped, and the focus confirmation chip (yep, it's in there) lights up your viewfinder when you hit focus, which is a thoughtful touch for a sub-$600 lens. For static subjects like landscapes or astro, it's a joy. For anything fast-moving, you'll miss autofocus in a heartbeat.

The natural rival in the Four-Thirds world is the Panasonic Leica 25mm f/1.4. That lens adds autofocus, better wide-open sharpness, and a more premium build, but costs significantly more. The Samyang fights back with a slightly wider field of view and a full stop more light than most f/2.8 zooms you might consider, like the Panasonic 12-35mm f/2.8. For astrophotographers who don't care about AF, the Samyang is the obvious choice. For everyday shooting and video, the Panasonic or a good zoom will save you a lot of frustration.

Prices swing from $549 to $752 across vendors, so you can snag a great deal if you shop around. The lower end of that range makes this lens an absolute steal for what it delivers in light gathering and bokeh. At the high end, you're getting close to used Panasonic Leica territory, where you'd gain autofocus. Worth it if you crave the fastest aperture on a budget and don't mind the manual life. We'd snag it near $549 and call it a win.

Here's the deal: Samyang's 24mm f/1.4 for Four-Thirds is one of the brightest lenses you can slap on an Olympus body without taking out a second mortgage. It's fully manual, which will either thrill you or drive you nuts. The f/1.4 aperture sits in the top percentile of all lenses we've ever measured, so you can practically shoot in the dark. Just know that wide open it's a bit dreamy, not surgical. Stop down to f/2.0 and it cleans up beautifully, especially for night sky work. If you're willing to meter and focus by hand, this lens rewards you with gorgeous bokeh and ridiculously low light capability.

If you need autofocus, weather sealing, or a lens that's sharp wide open for fast-paced events, skip this and get the Panasonic Leica 25mm f/1.4 instead. Also, if you're a travel photographer who values light weight and quick framing, this heavy, manual-only prime will slow you down. The Samyang is a brilliant low-light specialist, not an everyday walkaround.

Buy this if you're a budget-conscious astro or landscape shooter on Four-Thirds who lives on a tripod and loves manual control. The f/1.4 aperture opens up shots that f/2.8 lenses simply can't grab, and the bokeh is beautiful. But if you need a grab-and-go lens for events, street, or video, the lack of autofocus and the softness wide open will annoy you daily. It's a specialist's tool that does one thing brilliantly on the cheap.