Kase Reflex Mirror 150mm f/5.6 AF Lens 150mm

The Kase 150mm f/5.6 AF Reflex Mirror Lens has the worst optical performance we've ever recorded in this category, sitting at 0th percentile. But it's also the only autofocus mirror lens for Nikon Z, and owners seem genuinely happy with it, with user sentiment at 81st percentile. At $649 USD, it's a specialty purchase for people who want the donut bokeh look and compact size more than they want sharp images.

Let's rip the bandage off. The optical score is 0th percentile. Dead last. That means every other lens we've tested in this category beats it for sharpness, contrast, and overall image quality. The 5 elements in 4 groups design is simple, and mirror lenses are notorious for soft edges, low contrast, and that weird ring-shaped bokeh. The fixed f/5.6 aperture doesn't help either. You can't stop down for more depth of field or sharpness, and you can't open up for more light. What you see is what you get, forever. The minimum focus distance of 1500mm means you're not getting close to anything. Forget flowers, forget details. This is a lens for standing back and grabbing a compressed shot of something far away.

Autofocus lands at 54th percentile, which is about average. That's actually kind of impressive for a mirror lens, since most of them are manual focus only. The AF/MF switch is there if you want to take over. But there's no stabilization, and that's a problem. At 150mm on a full-frame body, you'll want a shutter speed around 1/150s or faster to avoid shake, and with a fixed f/5.6 aperture, you're going to be cranking ISO in anything but bright daylight. The bokeh score is 56th percentile, which is middle of the pack. The donut bokeh is the whole point of a mirror lens, and the Kase delivers it. Whether you find it pleasing or distracting is a matter of taste. We find it charming in small doses and headache-inducing in busy backgrounds.

Stacked against the competition, the Kase looks rough. The Tamron Di III VC 28-300mm f/4-7.1 gives you a massive zoom range with stabilization for similar money. The Sigma Contemporary 18-50mm f/2.8 DC DN is a completely different focal length but delivers far better optics and a brighter aperture. Even the Nikon NIKKOR Z 17-28mm f/2.8, which isn't a telephoto at all, makes the Kase look optically embarrassing. The Sony FE Distagon T-Star 35mm f/1.4 ZA is in another universe for image quality. The only place the Kase wins is size and uniqueness. It's shorter than any traditional 150mm lens, and it's the only autofocus mirror lens in this group. But you're trading away sharpness, contrast, flexibility, and build quality to get that compact form factor. For most people, that's a bad trade.

At $649 USD, the Kase 150mm f/5.6 is not cheap. For that money you could grab a used Nikon Z 24-200mm f/4-6.3 VR and get a zoom range, stabilization, and much better optics. Or you could pick up a vintage manual focus mirror lens for under $100 and adapt it. The Kase's main value proposition is autofocus on a mirror lens, which is genuinely unique. But you're paying a premium for that convenience while accepting bottom-of-the-barrel optical performance. The CAD price of $901 is even harder to swallow. If you're buying this, you're buying it for the specific look and the autofocus novelty, not because it's a smart financial decision. It's a specialty tool with a specialty price tag.

The Kase 150mm f/5.6 AF Reflex Mirror Lens is a weird little thing. It's a mirror lens, which means it uses mirrors instead of traditional glass elements to fold the light path, keeping the barrel short. That's the whole pitch: a 150mm telephoto that doesn't look like a telephoto. But the numbers tell a rough story. Our database puts its optical performance dead last, 0th percentile. That's not a typo. It's the worst optical score we've recorded in this category. The build quality isn't much better at 17th percentile. So what are you actually getting for your $649 USD? A compact autofocus mirror lens with a fixed f/5.6 aperture and that signature donut bokeh. Whether that's a feature or a bug depends on how much you love weird rendering.

Here's the thing though. The social proof is 99th percentile. People are talking about this lens. A lot. And the user sentiment score sits at 81st percentile, which means the folks who actually bought one are mostly happy with it. That's a strange gap: terrible optical scores on paper, but owners seem to enjoy it. Part of that is probably expectation management. Nobody buys a mirror lens expecting clinical sharpness. They buy it for the look, the size, and the novelty. And on those fronts, the Kase delivers something genuinely different in the Nikon Z lineup.

Skip this lens if you care about image quality at all. The 0th percentile optical score means every other lens in this category beats it for sharpness and contrast. Skip it if you shoot in low light, since the fixed f/5.6 aperture and lack of stabilization will force you into high ISO territory. Skip it if you want to shoot anything close, because the 1500mm minimum focus distance keeps you nearly five feet away from your subject. Skip it if you're on a budget, because $649 USD buys a lot of better glass. And skip it if you're expecting modern build quality, since the 17th percentile build score suggests corners were cut. This lens is for mirror lens enthusiasts and people who specifically want the donut bokeh look. Everyone else should look elsewhere.

The Kase 150mm f/5.6 AF Reflex Mirror Lens is a niche product for a niche audience. If you're a mirror lens enthusiast who wants autofocus and shoots Nikon Z, this is basically your only option, and you'll probably love it. The donut bokeh is there, the compact size is there, and the autofocus works well enough. But if you're looking for a general-purpose telephoto, run away. The 0th percentile optical score isn't a fluke. This lens produces soft, low-contrast images that will frustrate anyone expecting modern sharpness. The $649 USD price tag makes it a hard sell when far better lenses are available for the same money. Buy it for the weirdness, not for the image quality.