Everyone is going nuts over this new reflex lens. Don't they know how HORRIBLE reflex lenses are?

It's an incredibly exciting time of year for camera gear. With CP+ 2026 taking place last week in Yokohama, Japan, and The Photography & Video Show happening over four days from this weekend in Birmingham, England, there are dozens of shiny new camera lenses to get hyped about.

One that's been getting a lot of hype online is the Kase Reflex 150mm f/5.6 AF – a lens I was able to get my hands on when it was unveiled at CP+. But while I'm intrigued by this exotic optic, I'm also patently aware of an inconvenient truth: reflex lenses are terrible.

If you're wondering what a reflex lens (also known as a mirror lens or a catadioptric lens) is, I recommend our look at the history of these optics. Long story short, they use pairs of mirrors to replace a number of optical glass elements.

The upside is that this greatly reduces size and weight, enabling supertelephoto lenses – like the Tokina SZ 900mm Pro Reflex f/11 MF CF – to fit in the palm of your hand.

The downside is that this also greatly reduces the optical performance, meaning reflex lenses – like the Tokina SZ 900mm Pro Reflex f/11 MF CF – often perform horribly in terms of sharpness.

Taking the Tokina 900mm as a case in point, its sharpness score was about 63% lower than a conventional 800mm in our lab tests.

The optical compromises don't end there. Due to the mirror-based optical design, these lenses have a fixed aperture – again, great for size and weight but not so great for versatility. Though the double mirrors optics do imbue reflex lenses with very distinctive "donut" bokeh, so they do possess character in the out of focus areas.

The Kase at hand

So, back to the Kase Reflex 150mm f/5.6 AF. This is actually the brand's second mirror lens, following the Kase Reflex 200mm f/5.6 MF. And it's only fair to say that we haven't reviewed the first lens, so perhaps Kase has perfected the reflex formula that every major optics maker has long abandoned.

You might have noticed the difference in nomenclature – and the "AF" on the new lens does indeed stand for autofocus. Which is almost unique; I believe the Minolta AF Reflex 500mm f/8 is the only other mirror lens with autofocus. So that's a cool thing.

Kase is also suggesting that, at 150mm, this is the shortest focal length mirror lens – which it may very well be. Again, a cool thing. And it's quite compact for a 150mm lens; not impossibly small, by any means, but nicely compact.

Of course, 150mm is prime portrait lens territory. And portraiture might be a genre where the lack of sharpness and crazy-shaped bokeh works in its favor, being as you don't typically want portrait glass to be too sharp (unless your subject has flawless skin) and you'll likely be shooting wide open.

Well, on this lens you have no choice as your only option is f/5.6. Which isn't exactly the kind of aperture you typically associate with subject separation and blurry backgrounds – though you do get that donut bokeh. Whether you want it or not.

So color me intrigued by the Kase Reflex 150mm f/5.6 AF – intrigued, but incredibly cautious. It's novel, and exotic, and maybe a first-ever, but I'm definitely going to need a bit of convincing! There's no release date at present, but it's being launched for Sony E, Canon EF and Nikon Z – with a manual focus version for Canon RF.

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