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OM System 40-150mm F4 Pro Review

One of the biggest perks of the Micro Four Thirds system is larger zooms in smaller packages. Now, Olympus has re-branded. One of the first moves for OM System, along with a new OM1 flagship mirrorless, is to create the smallest fixed aperture telephoto yet: the OM System 40-150mm f4 Pro. Now, there’s the usual slew of fine print conditions attached to any claim of world domination. OM System says that it’s the smallest 300mm equivalent with a fixed aperture. And of course, the Micro Four Thirds format with the 2x crop factor and the narrower f4 is helping out here immensely. But, the OM System 40-150mm f4 Pro is still pretty small.

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The question is, how much is sacrificed to add “world’s smallest” to the bragging list? Besides the narrower aperture and the lack of “Olympus” on the label, the OM System 40-150mm f4 Pro is missing a few of the design features of the Olympus 40-150mm f2.8 Pro. But, the lens still delivers some pretty sharp, limited distortion images with flare that’s full of character.

Too Long; Didn’t Read

The OM System 40-150mm f4 Pro is a compact yet tough telephoto zoom lens for Micro Four Thirds. It lacks the manual focus pull-back switch of the similar f2.8 lens. An f4 on Micro Four Thirds isn’t very bright, pushing up the ISO more and delivering less background blur. But, this lens has some pretty fun flare and, despite being more affordable, is still sharp.

Pros and Cons


  • Very light and compact
  • Mostly metal build
  • IP53 rated dust and water protection
  • Simple to use
  • Sharp images with little barrel distortion
  • Flare is full of character


  • F4 on a Micro Four Thirds isn’t very bright
  • No manual focus switch or focus limiter switch

Gear Used

I used the OM System 40-150mm f4 Pro with the:

  • Olympus E-M1 Mark III
  • Tenba Fulton 16L camera backpack


OM System says the 40-150mm f4 Pro is the lightest, most compact 300mm equivalent zoom with a fixed aperture. It weighs just over 13 ounces and, when retracted, is less than four inches long. Indeed, it felt more like carrying a wide-angle prime than a 300mm lens. Of course, much of that weight savings comes from the narrower f4 aperture and the crop factor of Micro Four Thirds that pushes this lens to a 300mm equivalent.

Size isn’t the only innovation here. While weather-sealing is common, few lenses go through the tests to gain an IP rating that specifies just how much abuse it can withstand. The OM 40-150mm f4 has an IP53 rating. That means it’s tested for dust without harmful deposits and tested against water sprays up to 60 degrees from a vertical spray. OM Solutions also says it’s freeze-proof as well.

Tech Specs

OM System provided the following specifications for the 40-150mm f4 Pro:

  • Focal length: 40-150mm (80-300mm equivalent)
  • Lens construction: 15 elements in 9 groups (2 ED lens, 1 super ED lens, 1 HR lens, 2 aspherical lens)
  • Splashproof type: IEC Standard publication 60529 IP53 (applies when the lens is used with OM System (Olympus) splash proof body). Dustproof construction
  • Focusing system: High-speed imager AF (MSC)
  • Angle of view: 30-8.2 degrees
  • Closest focusing distance .7m
  • Maximum image magnification: Wide .07x Tele .21x (35mm equivalent wide .13x Tele .41x)
  • Number of blades: 7
  • Maximum aperture: f4
  • Minimum aperture: f22
  • Filter size: Diameter 62mm
  • Dimensions: 68.9 x 99.4 mm
  • Weight: 382g (without lens cap, lens rear cap and lens hood)


For shooting at the equivalent of 300mm on the long end, the OM System 40-150mm f4 is surprisingly small. The length of the lens doesn’t change as the focal length is adjusted. But, twisting the lens does make it more compact for storage. It will take up roughly a four-inch lens slot in a camera bag when retracted. 

The body is mostly metal, yet it weighs just over 13 ounces. Considering the reach, it’s not bad at all to tote around on long hikes. This lens feels more like carrying a wide-angle zoom than a heavy 300mm. It’s a lens I think many photographers could carry for miles. 

While the name of the lens is new, the overall design feels very familiar. Similar to other Pro line lenses, the 40-150mm has a large zoom ring and a small focus ring. But, it lacks the pull-back feature on the focus ring to enter into manual focus mode. This is disappointing because switching to manual focus on the body takes more time. With the pull-back ring to enter manual focus, it’s possible to manually focus on a bird within seconds when branches throw off the AF. Without, you’ll need to activate the AF override in the menu, or go into the quick menu to switch to manual focus. But, other lenses like the 12-45mm f4 Pro also don’t have the pull-back feature to enter into manual focus mode.

The lens has a simple, straightforward design. There are no Fn buttons or focal distance scale — just the two rings. There’s also no autofocus limiter switch.

The front of the lens takes 62mm. There’s a good bit of plastic around the front as well. It ships with a lens hood, which has a simple button lock.

Overall, the re-branded lens still feels true to Olympus style, with the exception of that pull-back ring to enter into manual focus mode. That ring is still found on the larger, pricier 40-150mm f2.8.

Build Quality

The barrel of the OM System 40-150mm f4 Pro is mostly metal. The exception is that, when the lens is extended, the piece that protrudes from the barrel is plastic. There’s also a bit of plastic around the front of the lens and the lens hood is plastic.

But, while many manufacturers will label a lens as weather-sealed but not say exactly how much weather is too much, OM System has added an official IP rating to this lens. With an IP53, the optic is tested to withstand most dust, as well as jets of water up to a 60-degree angle.

I shot with this lens in the cold and light snow. And then, since I didn’t think the light snow was really up to IP53 standards, I put it under the faucet. The lens continued to function normally, including smooth turns on both rings. I also didn’t detect any debris on the sensor after shooting with this lens.

“I shot with this lens in the cold and light snow. And then, since I didn’t think the light snow was really up to IP53 standards, I put it under the faucet. The lens continued to function normally…”


The OM System 40-150mm f4 Pro is capable of focusing as close as 27 inches from the front of the lens. At 150mm, that’s about a .41x macro on a 35mm equivalent. It gets in pretty close for a telephoto lens.

Shooting action, the lens performed well in sequential low burst mode. Photographing a runner heading straight towards the lens, I had only about a ten percent miss rate shooting at 10 fps.

However, focusing wasn’t perfect. I had more misses when photographing birds when the camera wanted to focus on a branch closer or further away. A focus limiter switch would have helped immensely. It’s not technically a macro lens, which is where you usually find focus limiter switches, but the range is big enough that such a feature would have helped. I turned on the focus limiter inside the camera menu instead and had much better performance. Having a focus limiter switch on the lens itself would have helped easily activate that mode when needed and turn it off when not.

Overall, the autofocus is decent — I just wish this lens had an AF limiter switch and the switch to enter into full manual mode. Both are still possible, but slower to access in the camera menus rather than on the body of the lens itself.

Ease of Use

The OM System 50-140mm f2.8 Pro couldn’t get much simpler to use. If you forget to rotate and extend the lens, the camera body will yell at you to do so. Then, there are just the two rings for zoom and focus. There are no extra buttons or controls. The good thing about missing the manual focus ring pull is that it makes the lens even simpler. I still remember shooting with this feature for the first time — I accidentally pulled the ring into manual mode and was puzzled when the camera wasn’t focusing. Beginners will find this lens pretty simple to use.

To keep this lens light and compact, there’s no stabilization system built-in. Olympus bodies typically have some pretty great stabilization though. I managed to shoot this lens at 40mm for a two-second exposure, though I had a much better hit rate with a 1.3-second exposure.

The most challenging part about using this lens is simply the narrower aperture. An f4 on a Micro Four Thirds sensor doesn’t let in a lot of light. While that stabilization helps for still subjects and intentional blur, the narrower aperture isn’t as ideal for action. I had to bump up the ISO a bit more than I like, which left the details more muddied.

Image Quality

OM System says this lens uses the same fundamental structure as the 40-150mm f2.8 Pro, with 15 elements in nine groups, with a narrower aperture and a lighter, more compact design. I found this lens plenty sharp with a good handle on fighting off aberrations and imperfections. But, as an f4 on a Micro Four Thirds sensor, bokeh isn’t as exaggerated. And, because the f4 lets in less light, compensating with a higher ISO leaves less detail.


Getting bokeh on an f4 Micro Four Thirds Lens (equivalent to f8 on full-frame) is tough to do. This lens isn’t a bokeh master. But, you can capture smoother backgrounds if you take advantage of the lens’ minimum focus distance and get in real close to the subject. Points of light are rendered into smooth bokeh balls, though they’re slightly more heptagon than circle shaped. The bokeh balls, however, don’t turn into a cat-eye shape on the edges. I also didn’t spot onion ringing or bubbling.


This lens is sharp, even wide open. The corners are slightly softer than the center, but still acceptable if you want to place the subject on the edge. The lens had similar sharpness at 150mm and didn’t drop off as zoom increased. That is, however, a bit unsurprising since the f4 means this lens doesn’t have a super narrow depth of field.

Lens Character

This lens can get some pretty wild lens flare if you shoot straight at the sun. With the sun in the center of the frame, this lens captured a disco ball of circular flare radiating from the light source. It’s actually a pretty fun effect, though the flare doesn’t look that way if the sun is partially blocked by the subject. That’s going to make it a bit tougher to use. If you place the light source on the edge of the frame, the lens creates some streaky light flare that I really like.

The lens has minimal barrel distortion at both 40mm and 150mm. Similarly, vignetting is very light. I did spot some occasional chromatic aberration, but it wasn’t often and it wasn’t distracting.

Color Rendering

The colors coming from this lens were consistent with what I’d expect from the E-M1 Mark III. Colors are a more neutral starting point, without being overly saturated or taking on other tones. Colors and contrast will naturally look a bit more washed out when lens flare is captured.

Extra Image Samples

From day one, The Phoblographer has been huge on transparency with our audience. Nothing from this review is sponsored. Further, lots of folks will post reviews and show lots of editing in the photos. The problem then becomes that anyone and everyone can do the same thing. They’re not showing what the lens can do. So we have a section in our Extra Image Samples area to show edited and unedited photos. From this, you can make a decision for yourself.





  • It’s easy to carry on long hikes because it’s very light.
  • The construction is mostly metal.
  • This lens is super durable and IP53 rated.
  • With fewer controls, the lens is simpler to use.
  • Images are sharp and there’s little distortion.
  • Pointing this lens at the sun can get some fun flare effects.


  • The f4 aperture requires pushing up the ISO more for action, which muddies detail.
  • I miss the manual focus control on the f2.8 version of this lens.

The OM System 40-150mm f4 Pro delivers the sharpness of a Pro line lens in a smaller, more affordable package. It’s simple to use, easy to carry around on long hikes, and I even dunked it under a faucet to no ill effects. This lens is pretty durable and feels great in the hands. The images are sharp and the lens flare is fun to work with.

But, there are a few sacrifices to get to that smaller size. An f4 lens on Micro Four Thirds means higher ISOs for photographing action, which translates into more noise and less detail. I miss the ability to simply pull back on the focus ring to enter into the manual focus the f2.8 version has. I also needed to limit the focus range in the camera menu to have more success birding.

The OM System 40-150mm f4 Pro lens retails for $899, available early March 2022. That’s about $500 cheaper than the f2.8 lens. It’s a good option when space and cash are limited, but the f2.8 is more ideal for limited light and action.

Overall, I’m giving the OM System 40-150mm f4 Pro four out of five stars.

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