A Coastal Wake-Up Name: Variable ND Filters vs Actual-World Mild

What I Loved within the Studio, and What Caught Me Out on the Coast

After spending time with the K&F CONCEPT Ultra-Low Reflection Variable ND Filter within the studio, I used to be genuinely impressed. Long exposures behaved superbly, reflections had been effectively managed, and picture high quality held up precisely as promised.

So naturally, it got here with me on vacation. Coastal mild, massive skies, transferring water… the proper playground for a variable ND, proper?

Well. Mostly.

When Reality Hits, Literally Full Sun

Out on the coast, capturing in harsh noon mild, I began noticing one thing I hadn’t seen within the studio in any respect. At increased ND strengths, particularly when working wider, components of the body would darken erratically. In some conditions, an unfamiliar “dark cross” or X-pattern began creeping in throughout the sky.

At first, I assumed one thing was flawed. A nasty copy? A coating situation? User error?

Turns out, it was none of these.

The Important Bit Most of Us Learn the Hard Way

This isn’t a fault with this filter, or with Ok&F CONCEPT particularly. Apparently, it’s a recognized bodily limitation of variable ND filters, apparently ALL variable ND Filters.

Variable NDs work by stacking two polarising filters and rotating them in opposition to one another. At stronger density settings, particularly in shiny daylight and with broad or ultra-wide lenses, mild enters the filter from a number of angles. Those angles don’t play properly collectively, and you find yourself with uneven polarisation throughout the body, which reveals up as that dreaded X-pattern.

In the studio, with managed mild and longer focal lengths, this by no means confirmed up. Outside, with open skies and brutal distinction, it completely did.

Lesson realized.

What Helped (and What Didn’t)

Once I understood what was occurring, I may work round it pretty simply.

Things that helped:

• Keeping the ND energy slightly below the utmost vary
• Avoiding ultra-wide focal lengths when stacking heavy ND
• Rotating the filter slowly to seek out probably the most even place
• Being extra selective about when a variable ND was really the best device

Things that didn’t:

• Pushing it to absolutely the ND400 finish in full solar
• Shooting broad seascapes with massive skies and anticipating excellent uniformity

This just isn’t distinctive to this filter. You’ll see the identical behaviour with most variable NDs, no matter model, when you push them laborious sufficient.

Variable ND vs Fixed ND, Choose Your Weapon

This shoot jogged my memory why many panorama photographers nonetheless swear by mounted ND filters for coastal and seascape work. Fixed NDs don’t depend on polarisation stacking, so that they ship much more constant publicity throughout the body, particularly in skies and water.

That doesn’t imply the variable ND all of a sudden turns into ineffective. Far from it.

For:

• Portraits outdoor
• Video work the place publicity wants fast adjustment
• Controlled compositions with out huge skies
• Travel and light-weight kits

A variable ND continues to be extremely sensible.

For:

• Bright noon seascapes
• Ultra-wide landscapes
• Critical lengthy exposures with clear skies

A set ND will often win. I actually just like the Magnetic Filter kits for this reason

The under photos are SOOC (Fixed ND Filter photos courtesy of Roy Powell)

Final Thoughts

I’m nonetheless glad I took the K&F CONCEPT Variable ND Filter with me. It carried out precisely as physics permits it to carry out, which is a crucial distinction. The situation wasn’t the filter; it was my expectations of what a variable ND can realistically do in excessive outside circumstances.

If something, this shoot was a great reminder that no single filter does all the pieces completely. Knowing the strengths and limitations of your instruments issues simply as a lot as proudly owning them.

And sure, subsequent coastal journey, a set ND will likely be within the bag as effectively. Consider this experience-earned knowledge, with a aspect of salty sea air.