Olympus 150-400mm F4.5 TC1.25x IS Pro at a glance:

  • 300-800mm equivalent range
  • 375-1000mm at f/5.6 via built-in 1.25x teleconverter
  • 28 elements in 18 groups; built-in TC 7 elements in 4 groups
  • 1.3 metres minimum focus
  • Weighs 1.875 kg without lens hood
  • 8 stops stabilisation with E-M1X
Olympus M.Zuiko Digital ED 150-400mm F4.5 TC1.25x IS Pro

Andrew with his Olympus 150-400mm f/4.5 TC1.25x and E-M1 Mark III

When Olympus announced the development of a 150-400mm F4.5 lens with a built-in switchable 1.25x teleconverter, many Olympus wildlife shooters, myself included, had a hunch that this could be a game-changer. And when the specs were announced, we all hoped it would live up to the hype.

Here was a lens that would shoot the full-frame equivalent of 300-1000mm, at a constant f/4.5 up to 800mm and then at f/5.6 with the 1.25x converter engaged. And for any detractors complaining that it’s not f/4, I would say that this was a canny move by a company known for designing fantastic small form-factor cameras and lenses.

It also had an incredible 1.3 metre minimum focus distance, allowing close-up pics of dragonflies and butterflies. And to top it all, it would take 1.4x and 2x teleconverters, meaning it could shoot at a mind-blowing 2000mm equivalent.

For many years, I had shot with Canon. I loved the sharpness and autofocus but did not love the bulk and weight. Already, moving from the EOS 5D Mark IV and 500mm f/4 to my OM-D E-M1 Mark III and 300mm f/4 had shrunk my kit bag hugely.

So why would I go for another ‘big white’ and lug around a giant telephoto again? But studying this lens before I bought it was reassuring.

My Canon set-up weighed a hefty 4.2kg, but this lens would come out at 2.5kg with my E-M1 Mark III – a serious weight saving. And this is a zoom with a built-in teleconverter; the equivalent Canon EF 200-400mm f/4L IS USM Extender 1.4x weighs 3.8kg alone. My only worry was that Olympus might be pouring money into its new flagship lens but that performance would not follow.

However, my other two Olympus Pro-series telephotos, the 40-150mm f/2.8 and the 300mm f/4, were bitingly sharp and I had faith that this lens would follow in the same vein.

Its 1.3m minimum focus distance makes the lens ideal for close-ups, such as this swallowtail in flight Olympus OM-D E-M1X, 220mm, 1/4000sec at f/5.6, ISO 1000

Build and handling

When the lens arrived in February, my worries proved unfounded. With a weight-saving carbon fibre reinforced plastic hood, magnesium alloy shell and sturdy tripod foot that was perfect for handholding, the lens that came out of the box felt solid but lightweight and extremely well engineered.

Pairing it with my E-M1 Mark III and E-M1X (which required the latest firmware upgrade) revealed that this was a wildlife lens that could easily be carried all day, with no tripod necessary. In the hand it feels solid and easy to lift. Once it locks on, Olympus’s IS is rock-solid even at distance.

This is, however, a serious wildlife lens that requires good technique to use. But I had five years of using the Canon 500mm f/4 handheld and so did not have a problem cradling the lens in my left hand and operating the camera with my right hand. All of the controls feel logical and particularly the teleconverter, which can easily be operated with your right-hand fingers as you are focusing.

The zoom is similarly smooth and quick, with the added bonus being that it is an internal zoom mechanism. In my first few months with the lens, I have crawled all over the Long Mynd and its light weight and small size has meant that I can get far closer to wildlife without alerting them to my presence.

It’s 600g heavier than my Olympus 300mm f/4, but what you get is easily worth the weight gain. Fieldcraft has simply become easier with this lens, though I would recommend using a shoulder strap such as a BlackRapid if you are carrying it for an extended length of time.

As you would expect with a lens of this calibre, there’s an array of buttons on the side. But the only ones I have used are the focus limiter, which is very useful to stop hunting if wildlife is nearer or further away, and the AF/MF switch when shooting from a tripod using Pro Capture, to nail the initial focus point.

The preset button could be handy if you have a perch that a bird keeps coming back to and you need to hit that focus point instantly, while you can also program the four buttons around the lens barrel for preset focus points. For times when a tripod is a must, the tripod foot has an in-built Arca-Swiss mount.

The internal zoom only requires a quarter turn across its full reach and in practice it’s fast to adjust.

I was able to shoot these barn owls at 2000mm equivalent, via the MC-20 teleconverter
Olympus OM-D E-M1X, 500mm + MC-20, 1/100sec at f/11, ISO 250


There is a perception that Micro Four Thirds plays second string to full-frame in terms of AF and yes, the E-M1X’s bird AF is not as fast as Canon’s version on the EOS R5 (which was incredibly speedy when I tried it recently with the RF 600mm f/4). But I found the 150-400mm to be like the 300mm f/4 on steroids, being both quick and eager to lock on.

I generally use a 5-point cross-shaped pattern for birds and animals and have captured some incredible moments. Combined with Olympus’s Pro Capture mode, which can continually buffer up to 35 frames and then record them when you press the shutter button, bird and butterfly in-flight shots can become an everyday reality.

But where it really excels is responding to unexpected situations like a hare popping up in a field, or a buzzard being mobbed by crows. There are plenty of times I have suddenly stopped my car and leaped out to try and capture what is occurring in front of my eyes. This is another area where size and weight make the difference.

It does not feel like I am trying to slowly turn around a lumbering tank to aim at a target, as with a massive full-frame set-up. Size really does matter and the lens’s nimbleness is matched by superbly responsive AF.

Pro Capture mode enabled me to capture this woodpecker taking flight Olympus OM-D E-M1 Mark III, 207mm, 1/2000sec at f/4.5, ISO 4000


None of the specs or the efforts Olympus made to bring this lens down in size and weight would matter if it did not deliver high- quality images. It did take me a couple of weeks to get used to the form factor and understand how the lens worked, but after that, I quickly stopped using my 300mm f/4, although I have kept my 40-150mm f/2.8 for butterflies.

A fair few Olympus shooters pair this lens with the E-M1X, and it is a nicely balanced combo, but my main goal if I am out all day shooting is to carry the lightest rig possible and for this the E-M1 Mark III better suits my needs.

Two things stand out in particular. Firstly, the extra reach. With one flick of a finger, the 1.25x converter is engaged and I suddenly have 1000mm equivalent reach handheld. Distant birds hidden in a tree can now become detailed portraits and a faraway bird in flight suddenly looks a lot nearer.

Secondly, the zoom has saved my bacon several times when suddenly, there is wildlife much closer to me, or I am worried about clipping birds’ wings as they take off. My field of view can be adjusted quickly on the fly, an option that was obviously not available with the 300mm f/4.

Of course, the proof of all this technological advancement is in the pudding. How do the raw files stack up in Lightroom? The answer is very pleasing.

The images, when exposed properly, have great definition, contrast and detail. Surprisingly, going from f/4 on the 300mm to f/4.5 at 400mm gives me both extra reach and a tiny bit more depth of field, which is useful for birds in action. The weather-sealing has meant I have gone out in torrential rain and not worried about my set-up for a second.

I do feel that Olympus built this lens to be as rugged and reliable as its counterparts and to deliver stellar performance, which it does in spades. The images have proved to be easily good enough for my media work in magazines and for the national papers.


The Olympus 150-400mm F4.5 TC1.25x IS Pro really is a case of you get what you pay for. It’s an incredibly lightweight, blazingly fast-focusing, seriously sharp, highly engineered marvel of miniaturisation with an equivalent reach that ranges from 300mm all the way to 2000mm with a 2x teleconverter added.

For stalking wildlife it is both subtle and small and I am sure this would carry over to sports shooting. The quality of the results has been easily good enough for publication, as well as for my ongoing commission for the National Trust. This lens now stays on my E-M1 Mark III or E-M1X all the time, and I look forward to travelling with such an easy to pack and carry set-up. Now we just need an updated body and sensor that can take the lens to its limits.

Using the 150-400 with teleconverters

This lens is compatible with Olympus’s MC-14 and MC-20 1.4x and 2x teleconverters, which lead to a 1400mm equivalent lens at f/8 or a whopping 2000mm at f/11, still with full AF functionality. The converters are small, lightweight and genuinely useful. Indeed this level of reach is a game-changer: the 1.4x got me in close to a sitting hare, with the image quality nearly perfect.

Using my knee as a tripod enabled me to get a sharp result at 1/60sec. Olympus E-M1 III, 400mm + MC-20, 1/60sec at f/9, ISO 2500

Put on the 2x and the results are surprisingly sharp, although diffraction will make a difference, as will heat haze over long distances. But I still managed to photograph a pair of barn owls from far enough away not to disturb them. Such reach can also be useful for extreme moon and sun shots, making them appear large in the frame and within the context of the landscape.

I had never thought to aim for a man in the moon shot before, but this lens opens up new and extraordinary possibilities. You can still handhold at such extreme focal lengths, but a helpful fence post, or sitting down with the use of a knee as an improvised tripod, will give you more stabilisation. As ever with Olympus, the image stabilisation is absolutely fantastic, but at 2000mm things can get shaky.

Affordable alternatives

There is no getting round the fact that this is an expensive lens, although put up against full-frame equivalents like the Canon 200-400mm f/4, it’s a steal. But Olympus also recently introduced a more budget-friendly alternative, the M.Zuiko Digital ED 100-400mm f/5-6.3 IS.

The Olympus 100-400 f5-f6.3 is a great and very sharp budget alternative but works best in good light.

I borrowed a copy for the purposes of this article and given the £1,099 price, it’s surprisingly sharp at both ends and can produce some fantastic images in good light. There is also the M.Zuiko Digital ED 300mm f/4 IS Pro at £2,249, which was my go-to lens for three years. This is an amazing wildlife lens that takes the 1.4x and 2x teleconverters, and is both compact and lightweight.