OPF 550-S takes OPF 550-L’s idea of a filter you want to leave on every day one step further.

There was, however, a stumbling block along the way. This article follows that setback through to the redesign. In the second half, six photographs taken in everyday light show how it turned out.

01 — How it beganA little too strong with wide-angle lenses

In backlit scenes, OPF 550-L controls strong light and lets light itself become the subject.

The OPF L series consists of filters that diffuse light. Naturally, a wider angle of view brings more light into the frame. This is why the diffusion effect looks stronger with shorter focal-length, wide-angle lenses.

In video shot with wide-angle lenses and in everyday snapshots, there are times when the effect can feel a little too strong. We wanted something more restrained. That was the starting point for OPF 550-S.

02 — A stumbling blockWe thought less diffusive glass would be enough

The initial idea was simple: replace the light-diffusing glass with glass that diffuses less. We started development thinking it would be straightforward, but the first prototype did not work at all.

Photographs taken with the prototype were dominated by flare and ghosting. These are rings or streaks of light recorded when strong light reflects inside the lens.

With OPF, the glass diffuses light, while the coating determines how flare and ghosting appear. The two depend on a balance. Reducing the diffusion of the glass alone upset that balance.

03 — The redesignStarting again with the coating

So we also redesigned the coating, which determines the wavelengths emphasized and the way flare and ghosting appear.

We have been developing filters for more than 60 years, ever since our founding in 1965. Even so, reducing only flare and ghosting while keeping the color response sounds simple but is genuinely difficult. And few people notice the effort. A successful development is one that goes unnoticed—a slightly bittersweet thing to care so much about, really (laughs).

After much trial and error, OPF 550-S became a filter that retains what we like about OPF 550-L while controlling light diffusion, flare, and ghosting more subtly. Its color rendering is also just a little different from OPF 550-L. To put the difference in numbers as an analogy, it is as small as 550 versus 548. Both coatings act on the reflection and transmission of light around 550 nm, but each is adjusted to suit its own design.

So how does the redesigned OPF 550-S render everyday light? Let’s look at six photographs to see how it turned out.

04 — Putting it to the test 1A beach in strong sunshine

A midsummer beach seen from beneath a parasol. The sky is blue, and the wave crests shine white. The sun is outside the frame.

Even in strong sunshine, OPF 550-S adds subtle depth to colors when the sun is outside the frame—the beige of the sand and the blue of the sea, for example. Outlines and fine detail remain intact. The changes are restrained because we designed it to be left on every day.

05 — Putting it to the test 2A green wall and tree shadows

Tree shadows fall across a pale green wall. Bicycles line up in front of it—an ordinary bicycle parking area you could find anywhere.

OPF 550-S also acts on light around 550 nm, in the green part of the spectrum. That said, the green is also the wall’s own color. What we would like you to notice here is how the shades of the shadows and the pale green sit quietly together in a single frame.

06 — Putting it to the test 3The shoreline and sunlight through leaves

The low late-afternoon sun makes a band of light across the wet sand. Around the reflection, the light diffuses just a little. Controlling strong light with restraint—that is the design of OPF 550-S.

Looking up at sunlight through the leaves, you can distinguish each overlapping leaf. The yellow leaf in the foreground is out of focus because of where the focus was set. Blur caused by focus and light diffusion caused by the filter are different things.

07 — Putting it to the test 4Flare remains, quietly

A pale pink-to-purplish arc stretches across a blue sky with birds in flight. It is flare drawn by the sun entering the upper-left corner.

Even after redesigning OPF 550-S to keep flare from becoming too prominent, we have retained it in a restrained form. When the conditions are right, it appears in the photograph like this. Shifting the framing just a few millimeters changes the arc’s position. Try moving it little by little until it falls where you like.

08 — Putting it to the test 5A room by the window

The last photograph is indoors. Plants stand in front of the white light coming through a frosted-glass window. However bright the window, the outlines of the leaves remain intact.

You can leave the filter on indoors, too. We feel this photograph clearly expresses our development goal: a filter you can keep on every day.

09 — Making your choiceChoose OPF 550-S or OPF 550-L to suit your taste

The development notes also share the writer’s own preference: OPF 550-L for brighter photographs, and OPF 550-S for darker ones. They also encourage readers to compare the results and choose for themselves, because tastes differ.

For the full development story and comparison photographs, see the OPF 550-S Development Notes.

USER VOICEWhat light do photographers use it in?

Here are excerpts from interviews with photographers who use OPF 550-S.

THIS WEEKENDSomething to try this weekend

1. Leave the filter on during a sunny walk, and shoot in a direction that keeps the sun outside the frame.
2. Under sunlight filtering through trees, look for light that diffuses subtly.
3. Place the sun in a corner of the frame and shift the framing a few millimeters at a time to see how the flare changes.
4. Keep the filter on indoors and photograph plants by a window.

OPF 550-S aims for a sense of calm and nostalgia. A photograph by a window that, years later, might bring back the quiet of that room. How it feels is different for everyone who sees it.

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OPF 550-S [BASE]

Leave it on in everyday light. Control strong light with restraint.

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