OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro review: Is this really the "Holy Grail" lens for MFT?

The OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro is undoubtedly the ‘grail’ lens for any wildlife or sports photographer with a Micro Four Thirds (MFT) camera. And what better camera to test this monster "Big White" optic than the flagship OM System OM-1 Mark II?

These two MFT titans combine to create a truly formidable pro-grade package. The lens itself delivers an incredible 35mm equivalent zoom range of 300-800mm, extended to a whopping 375-1,000mm with the built-in 1.25x teleconverter. Add an external 2x teleconverter to the mix and you get 2,000mm!

And while it’s a huge lens for a system that’s known for its pint-sized optics, the OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro still exceedingly small and light for a lens of its class.

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This OM System classic is, without a doubt, targeted at the most serious MFT wildlife / sports enthusiasts and professionals on the planet. So, I decided to visit both WWT Slimbridge Wetland Centre and the Hawk Conservancy Trust to put this top-tier optic through its paces, photographing birds in flight.

The question on my mind is whether its premium build and performance are enough to justify that premium price tag…

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OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Specifications

OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Price

The OM System M.Zuiko Digital ED 150-400mm f/4.5 TC1.25X IS PRO is not a cheap lens. It retails for $8,999.99 / £6,799 / AU$11,999, making it the most expensive optic in OM System’s lineup by some margin and the most expensive MFT lens on the market.

This is because it represents the pinnacle of OM System’s optical engineering and feature set. This may jar with some users because the MFT system is often framed as a more cost-effective alternative, especially when it comes to premium bodies and optics.

It’s difficult to compare the "Big White" to OM’s competitors because it offers an equivalent zoom range and speed that simply isn’t available in full-frame.

The Nikon Z 400mm f/4.5 VR S retails for around half the price at $3,499.95 / £3,299 / $5,499, but it’s a prime lens and doesn’t have a built–in teleconverter.

At the other end of the spectrum, you have the Nikon Z 400mm f/2.8 TC VR S, which has a built-in 1.4x teleconverter, but is also a prime and has a faster maximum aperture. This lens retails for roughly twice the price of the M.Zuiko 150-400mm f/4.5 at $14,699.95 / £13,499.00 / $24,299.00.

It’s a similar story when it comes to both Sony and Canon, but perhaps the closest offering is the relatively recent Sigma 300-600mm f/4 DG OS Sports, which retails for $6,599 / £5,899 / AU$12,995, although it doesn’t have a built-in teleconverter.

Ultimately, though, the OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro sits right within the mix of the world’s most premium lenses and, in that respect, it offers up a comparatively middling price point.

OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Design & Handling

When I first picked up the OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro, I was struck by two things: its weight and build.

The lens weighs 1,875g / 4.13lbs (without lens hood and cap) and measures 314.3 x 115.8mm, which is comparatively huge compared to other MFT lenses, but comparatively small next to range-topping full-frame lenses.

To put that into perspective, you’re getting a full-frame-equivalent focal length of 300-800mm (375-1,000mm with the teleconverter) in a package that you can actually handhold. The lens hood is big and solid, but a carbon-fiber build means it’s also surprisingly light.

That said, wildlife photography often requires an awful lot of waiting around – and holding a near 2kg lens for long periods of time will fatigue any photographer, so I’d still opt to bring a tripod, monopod or beanbag in reserve.

The good news is that the lens is light enough that you don’t have to pair it with a hulking tripod that weighs you down. My Manfrotto Befree Advanced travel tripod had no problem accommodating it.

When it comes to the lens’ build, it reminds me very much of a pro-grade DSLR optic. I’ve often thought that premium DSLR glass feels slightly more solid than most top-tier mirrorless offerings, so I mean that entirely as a compliment.

Its magnesium-alloy construction might be light, but it feels reassuringly solid in all aspects, from the barrel to on-board controls. I’m also a sucker for an internal zoom, which adds a premium feel to any lens.

I’ve personally never encountered a species that’s more bothered by a white lens than my presence, but some wildlife photographers like to cover white lenses in a camo skin, of which plenty are available specifically for the OM System 150-400mm f/4.5.

However, the white paint job doesn’t just look good; it serves a purpose as part of a three-layer heat-repellent coating.

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As you’d expect from a Pro-line OM System lens, the 150-400mm f/4.5 has an extensive IP53 rating, meaning it’s splashproof and dustproof.

I carry a rain cover in my camera bag at all times and won’t trust any standard camera or lens in a consistent downpour, but I did use the 150-400mm f/4.5 on a day with frequent light showers and felt entirely confident that not only would it hold up but it could weather plenty more.

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You’ll have to forgive me for waxing lyrical about a tripod collar and foot, but the designers have thought about almost everything in this instance. It’s a shame that the tripod collar isn’t removable to shed even more weight – although the foot can be removed – otherwise this is a near-perfect feature.

The foot is Arca-Swiss compatible for quick release/attachment, and I’m particularly impressed by the rubber lining on the inside surface. I can only assume this is so you can use it as a handle when carrying the lens around, without worrying about it slipping out of your hand in wet or sweaty conditions.

You’ll find two attachment points on the collar for a strap and, while you can rotate the collar to level your horizon at any angle, it also clicks securely into four different positions set at equidistant intervals at twelve, three, six and nine o’clock – each lining up perfectly with one of four custom buttons set further down the barrel.

These buttons are set before the focusing ring so you’re in no danger of inadvertently nudging it.

Both the focus and zoom rings are suitably smooth and the throw of the zoom is short, so you can quickly amend your framing.

The switch for the built-in 1.25x teleconverter is cleverly positioned on the right-hand side of the barrel, very close to the host camera’s grip. This enables you to toggle the converter on/off by extending a single finger while still clasping the grip.

With a little practice, you’ll start to do this instinctively, without pulling your eye away from the viewfinder. The switch also features a locking mechanism, which is a neat touch, although I found the switch itself to be robust enough that you’d have to be really unlucky to trigger it by accident.

And while it’s purely cosmetic, I really like the blue band that frames the lens’ front element. It’s a little touch that screams quality.

Unfortunately, the drawstring canvas bag that comes with the lens is a bit of a letdown, especially if you were anticipating the robust kind of cases that come with Sony, Canon and Nikon’s range-topping wildlife optics.

There’s minimal padding around the barrel, more padding around the base (but not enough) and although it was workable, I couldn’t completely close the bag with the OM-1 Mark II attached.

OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Performance

Real-world testing presents difficulties when working with super-telephoto optics due to phenomena such as heat distortion and camera shake.

Camera shake is the bane of the super-telephoto photographer’s life, but the first thing I noticed about the OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro is just how stable it is.

Despite that monster 35mm-equivalent 1,000mm potential, the Sync IS (optical image stabilization) achieved by the lens and OM-1 Mark II working in tandem delivered up to 8 stops of compensation – meaning I was rarely bothered by camera shake.

In a world where high-resolution sensors are causing photographers to double or even triple the reciprocal rule, it’s a joy to shoot with a long lens (and camera) that isn’t working against you. And of course, that constant f/4.5 aperture certainly helps in poorer lighting conditions.

I did notice some chromatic aberration, but this was easily mitigated via editing software corrections.

When it comes to overall image quality, the OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro performs very well, but stops short of being exceptionally sharp. Even for a lens that debuted in 2021, I couldn’t help but feel slightly left wanting from what is ultimately a range-topping optic in a very high-end price range.

However, it’s also important to remember that the equivalent focal range made possible by an MFT sensor means you’re getting much closer to the subject than you would with a full-frame setup. This, in turn, reduces the amount of cropping required, meaning you’re less likely to hack away at the resolution of your images.

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What impressed me was the quality of the built-in teleconverter, which really doesn’t impact image quality that much at all. Really, the only penalty is the narrower aperture; beyond that, the teleconverter feels a little like a cheat code in the best way possible. So much so that I could easily forget it was engaged.

OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Sample Images

The following gallery of sample images was captured with the flagship OM System OM-1 Mark II at both the Hawk Conservancy Trust and WWT Slimbridge.

This meant that I was able to test the lens in a challenging real-world environment by photographing birds in flight, while also dealing with inclement weather.

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OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Lab Results

Our lab manager, Ben Andrews, runs a variety of tests in controlled conditions using the Imatest Master testing suite. Photos of test charts are taken across the lens’s zoom and aperture ranges (where available), which are then analyzed for sharpness, distortion and chromatic aberrations.

Imatest SFR (spatial frequency response) charts and analysis software are used to plot lens resolution at the center of the image frame, corners and mid-point distances, across the range of aperture settings and, with zoom lenses, at four different focal lengths. The tests also measure distortion and color fringing (chromatic aberration).

Testing a super-telephoto Micro Four Thirds lens is always a challenge. The 2x crop factor means that you need to allow for double the distance between lens and test chart, compared to a full-frame lens.

Consequently, Ben was not able to test the 150-400mm at its full 400mm zoom. There simply isn’t enough space in the lab and, because lighting must be carefully controlled, outdoor testing is not an option. The best he could achieve was 367mm – and even this required a shooting distance of over 18 meters.

Sharpness:

Sharpness in the central region is good, although never particularly special. You do, however, get very good consistency throughout the focal range. Only at f/16 and narrower does center sharpness really dip. Corner sharpness is noticeably softer, though consistency across all focal lengths and apertures is excellent.

The lab also tested the optic’s sharpness at 150mm with the inbuilt 1.25x teleconverter enabled, resulting in a 187.5mm focal length (equivalent to 375mm). Teleconverters often noticeably reduce sharpness, but in this case, the reduction is minimal, and sharpness remains consistent with the results at other focal lengths.

Fringing and distortion:

There is some chromatic aberration, but it's not strong enough to be obvious in real-world shooting. And thanks largely to firmware-based distortion correction, which cannot be disabled, the lens appears to be almost distortion-free.

OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro: Verdict

The OM System M.Zuiko 150-400mm f/4.5 TC1.25X IS Pro is a bit of an oxymoron in that it’s a large, $9K / £6.8K / AU$12K optic for a system that’s built around the concept of portability and affordability. And yet, compared to full-frame range-topping super-telephoto optics, it’s significantly cheaper and lighter.

This isn’t the lens for your average MFT photographer; it’s a serious piece of equipment for a dedicated enthusiast or wildlife / sports professional.

When it comes to the design and build of the 150-400mm f/4.5, it’s about as good as it gets. It’s an absolute joy to operate and carry around, and it’s a rare example of a super-telephoto lens that I actually like to look at. It’s a bit of a beauty to say the least.

The price tag and top-tier status can draw unavoidable but unhelpful comparisons with full-frame glass, but it’s important to remember that these lenses tend to be twice the price and sit on sensors that are twice as big.

That said, I did expect slightly better image quality in both lab and real-world testing, although the quality of the teleconverter and image stabilization was extremely impressive.

Ultimately, the design and operation of this lens blew me away, the performance felt solid, if not quite exceptional. And yet, this lens undoubtedly complements Micro Four Thirds’ inherent advantages.

The monster zoom range and built-in teleconverter will get you closer to subjects than ever before. Its premium handling will increase your chances of capturing the moment you envision.

A small MFT sensor’s superior stability synced with this lens’ excellent optical image stabilization will enable you to shoot at slower shutter speeds without experiencing camera shake. And its rock-solid build and weather sealing mean it can accompany you on dusty safaris, in muddy forests and on damp hills.

Alternatives

If you want even more reach and don't mind sacrificing that constant f/4.5 aperture, then take a look at the OM System M.Zuiko 150-600mm f/5-6.3 IS. It’s an extremely large lens for the MFT system and it’s not the sharpest tool in the camera bag, but it’s well over half the price of the ‘Big White’.

The OM System M.Zuiko Digital ED 50-200mm f/2.8 IS Pro is a truly groundbreaking optic and although it certainly isn’t cheap, it’s still roughly half the price of the 150-400mm f/4.5. It’s sharp, it’s IP53 weather sealed, and it even boasts 1:1 macro. This could be an MFT wildlife photographer’s dream lens.