The Four Outstanding OM System f/4 PRO Zoom Lenses: We Review the Range

In photography, faster lenses are better, aren’t they? Many struggle to see the benefits of having a range of f/4 lenses. But, if you start using them, you’ll realize there are good reasons for challenging that assumption.

I recently wrote about why so many photographers are jumping to Micro Four Thirds and, specifically, the OM-System. So, why are the OM System f/4 PRO range of lenses so appealing?

You Can't Ignore the Laws of Physics, But You Can Use Them to Your Advantage

Firstly, there are the laws of physics and the design of every lens. At very wide apertures, all lenses exhibit aberrations to a greater or lesser extent. These are the flaws that are seen in the final image. Without going into too much technical detail, the most common and widely known of these is chromatic aberration, the green or purple fringing you can see along high-contrast edges.

It’s caused by the lens's inability to converge the different wavelengths onto a single point, so the white light is split as it would be through a prism. Spherical aberration is caused by light rays entering the lens that don’t converge at the same point, so incoming light at the edges of the lens hit the sensor at the wrong angle. Those aberrations, as well as other optical issues, are most prevalent at wide apertures.

There are things that camera manufacturers do to limit these faults, but most photographers are aware of their lenses’ sweet spots that sit a long way from the wide-open aperture. Consequently, a lens already stopped down to f/4 has inherent sharpness at its widest setting.

Admittedly, modern glass technology has made this argument redundant on the system’s PRO lenses; even their fastest lenses perform exceptionally well at wide apertures. So, there must be more to it.

Scalpel Sharp Images From the Lenses

Exceptional sharpness is especially noticeable with the OM System f/4 collection because they are built to the high standards of the PRO lineup. Consequently, they benefit from the exceptional quality glass, fast and accurate focusing resulting from the advanced engineering, and the beautiful bokeh from the diagram that comprises circular aperture blades.

Besides being quick and accurate to focus, they are silent in operation too. That’s a massive advantage for wildlife, event, and wedding photographers alike.

Ease of Focus

Especially at longer focal lengths, f/4 lenses are also easier to focus correctly than fast lenses because there is an increase in depth of field (DOF).

A mistake many rookie photographers with a fast lens makes is to always shoot wide open, thus having too little of the subject in focus and losing the context in the background when it would be welcomed. They also miss the critical focus because the camera locks on to the tips of the eyelashes or insect tentacles and not the eye. Moreover, if the photographer moves slightly between locking focus and releasing the shutter, that focus is lost. In those situations, experienced photographers stop down to give a bit of leeway.

Aperture, of course, is only one contributing factor to DOF, and it is still perfectly possible to achieve that sometimes clichéd look if that’s what you want. However, shooting at f/4 also means you can get an entire bird or person’s face in focus.

Yet, it is still possible to get a very narrow Don and a blurred background with the OM System f/4 range of lenses if you know what you are doing.

M.Zuiko f/4 Lenses and Low Light

Another factor is that new sensor technology has made a vast difference with low-light, fast shutter photography perfectly feasible because of the superb noise control in the most modern cameras. Even with older cameras, AI-based noise reduction has revolutionized high-ISO photography. Furthermore, the OM System cameras, such as the OM-1 and the OM-5, also have outstanding image stabilization, so low-light shooting that doesn’t require a fast shutter is possible too.

Further Advantages of These Lenses

Hang on, I hear you ask, could you not just buy a faster lens and step it down to f/4? You could, of course, but there are other advantages too.

Firstly, there is the size. One of the big advantages of the OM System is the small dimensions of the gear, especially the lenses. It is so much smaller than other systems’ equipment, making it ideal for photographers who want lighter, less bulky, and more discrete photographic gear. Having access to their PRO lens performance in an even smaller package makes them ideal for most genres of photography.

The Compromises of Getting Smaller

If you want smaller, high-performance gear, there are compromises to be made, and that means leaving some of the extra features that usually are featured in the OM System PRO lenses.

Let’s compare the two 40-150mm PRO lenses. The excellent Olympus M.Zuiko Digital ED 40-150mm f/2.8 PRO Lens has a focus clutch that lets you quickly and easily swap from auto to manual focus, and an additional programmable function button. It weighs just 1.67 lbs (760 g) and its maximum length is 6.28" (159.5 mm), much smaller and lighter than achieving equivalent reach with full frame lenses; because this is part of the Micro Four Thirds system, it gives the equivalent reach of an 80-300mm lens on a full-frame camera.

However, the f/4 equivalent, the OM SYSTEM M.Zuiko Digital ED 40-150mm f/4 PRO Lens, weighs just 13.5 oz (382g) and is just 3.9” (99mm) long. Like its big brother, it retains a constant f-stop throughout its zoom range. Furthermore, it’s far cheaper, currently retailing at $699 at B&H. To achieve that smaller size, it lacks all those bells and whistles. But it is still a fabulously sharp lens and the one that is usually attached to my OM-1.

When I travel, I can put a couple of f/4 lenses in my hand luggage along with an OM-1 and not worry about being overloaded. But just because the lenses are small and light doesn’t mean they are not well made. They have a sturdy all-metal construction and a smooth professional feel to the zoom and focusing rings reminiscent of the quality lenses we used to get in the heyday of film photography.

It's a Good Time to Buy OM System f/4 PRO lenses

B&H currently has a sale on these f/4 lenses, saving around $200 per lens.

Olympus M.Zuiko Digital ED 12-100mm f/4 IS PRO Lens: $1199

Olympus M.Zuiko Digital ED 12-45mm f/4 PRO Lens: $699.99

Olympus M.Zuiko Digital ED 8-25mm f/4 PRO Lens: $899.99

OM SYSTEM M.Zuiko Digital ED 40-150mm f/4 PRO Lens: $699.99

In the UK, there is currently a £175 cashback deal on the lenses. One can expect similar promotions in other parts of the world too.

What I Like and What Can Be Improved About the Lenses

It’s hard to fault this series of lenses. They are made to be portable and sharp. I use the M.Zuiko Digital ED 40-150mm f/4 PRO Lens on one camera when shooting weddings and events because it is fast enough to use indoors in low light and small enough to be discrete.

Like all the OM System lenses, they are splash- and freeze-proof, in most cases to IP53 standard, which matches the OM-1 and OM-5 cameras.

Although not macro lenses, they can focus close and are silent when both zooming and focussing.

Because of their even smaller size and weight, they are probably produced with the OM-5 owners in mind, and they are well-balanced on that camera. However, I happily use them on my OM-1 and my older E-M1 models, and they don’t look or feel out of place on those cameras.

There are situations they are less well suited for. I probably would not choose an f/4 lens for astrophotography, where we want to get the maximum amount of light possible onto the sensor. If you want extra stops of brightness, then other lenses are available. As with everything in photography, whatever we choose to use, there is always a compromise. However, these are fabulous, lower-cost, professional-grade, precision lenses.

For most photography, these are no-nonsense, high-quality lenses I can highly recommend to accompany any Micro Four Thirds camera.