The secret life of behind-the-lens nets

This is one area where experimentation really pays off.

“What’s with the pattern in the headlights?” I asked the first camera assistant, as I looked through “B” camera on a feature film set. I was a young second camera assistant, and a bored first camera assistant let me play around with the geared head while we waited for our camera to be tossed into the fray. I’d seen that each lens had a net glued across the rear element, but I hadn’t yet seen the effect. It was night, and as I looked down the street through a 75mm lens, I saw the texture of the net in the glow of out-of-focus car headlights.

“Not my department, kid,” he said. “I just keep it in focus.”

I didn’t use much diffusion filtration when I shot film. Later in my career, when I found myself shooting lots of video, I was more willing to experiment. At that time, video cameras had a reputation for being too sharp, and a lot of cinematographers used rear nets to take the edge off the image. Front filtration required a matte box, and a lot of jobs either wouldn’t rent one or moved too fast to make using one worthwhile. Rear nets were easier to manage.

A San Francisco Bay Area cinematographer, Jim Iacona, saw an opportunity to both make his life easier and make a buck at the same time. He invented the I-Ring, which came in two parts: a base that slipped onto the back of a B4-mount broadcast zoom lens, and a ring that clipped onto it. To use it, you’d stretch a net over the base, clip it on with the ring, and then trim away the excess material.

Ad for the I-Ring, circa 2003.

I had at least four of these ready to go at any given time.

As HD took off, I spent less and less time with nets. The Sony F900 looked sharp out of the box but turning the detail enhancement down to about -40 (in what I call “Sony Arbitrary Units”) resulted in a pleasing look. (Turning the detail circuit completely off worked well for feature films but, strangely, resulted in an image that was too soft for broadcast.) The original Panasonic Varicam had a natural softness to its image that didn’t respond well to additional diffusion.

Until recently, I hadn’t tried nets on single sensor cameras, as the only ways to do this involved rubber cement or nail polish. As a DP, I shot mostly commercial and corporate projects. Neither of those methods was appropriate for use on a one-day project.

When I saw the rear magnetic holder on the back of an ARRI Signature Prime, I immediately flashed back to that cold night on a dark Hollywood street. I decided it was time to refresh my knowledge of how rear-mounted nets work.


Left: Fine black tule. Middle: Black sparkle mesh. Right: Silver sparkle mesh.

I spent about a half hour at a fabric shop (Joann Fabrics, for those of you in the U.S.) before settling on the choices above.

My favorite net for B4-mount broadcast work was bobbinet, which is the material used in grip nets. The material at the far left, fine black tule, is a variant on this theme, but with a finer weave. The holes are hexagonal, and very round, so flares glow instead of radiating as star patterns. (Hard-edged holes in a net result in sharp, angular flares.) A lot of my broadcast video contemporaries used wedding veil, which has a very shiny, square weave, but this created four-pointed stars around even the softest highlights. That wasn’t my style.

Black sparkle mesh looked like fun. It was coarse enough and dense enough to work well as diffusion, but I didn’t know what its texture might impart to the image, or whether it would fall completely out of focus. It’s one thing for the pattern of the net to show up in soft highlights, but quite another for it to appear overlaid on a sharp subject.

Lastly, I chose silver sparkle mesh under the assumption that if black sparkle mesh turned out to be fun, silver sparkle mesh would be ten times as much fun.

Now that third-party LPL mounts are fairly widespread, I’ve been shooting a lot of tests with ARRI Signature Primes on non-ARRI cameras. Last week I had a Sony Venice in house, so while shooting another project I took the opportunity to conduct a quick net comparison test. With the camera set to EI 500 and X-OCN ST, I quickly set up and shot a net comparison.

ARRI Signature Prime. 125mm, T1.8. Sony Venice, X-OCN ST. No net.

Film is an abstract medium. It has a number of characteristics that digital doesn’t: grain, gate weave, layered color records, and an inability to view the results in real time. Because of these traits, dailies possess an element of surprise. The combination of texture and movement, even in a static image, and the fact that the exposure and color often looked better than we remembered when we captured the image, lent film a bit of a mystique.

Digital is often referred to as being too “clean,” and I’ve come to interpret this as meaning it lacks abstraction and mystery. Digital is predictable. There’s no gate weave, noise is not the same as grain, and you can (roughly) see what you’re getting while shooting. We generally know what we’re going to get, and some cinematographers don’t like that. They want, say, 10% of that process to be imperfect. They yearn for the “creative surprise.”

As an industry, I think we’re trying to recapture some of that mystery through the use of vintage glass. Flares, distortions, spherical aberration, and other optical anomalies capture some of that creative unpredictability that we enjoyed with film. This presents a quandary for ARRI, as we’ve always made lenses at the cutting edge of physics. Our lenses are beautiful, but they are intentionally beautiful. There aren’t a lot of random surprises.

Fortunately, the product manager for our optical products has a long history of classical lens admiration. For the Signature Primes, he opted to start with a perfect lens but then incorporate some classical lens features. Even though Signatue Primes are almost entirely free of distortion, spherical aberration, and chromatic aberration, Signature Primes are also slightly warm (to pop flesh tone), appear low in contrast (due to lack of focus ramping), are low in micro contrast (for smooth skin tone even at extremely high resolutions), and crafted to flare subtly rather than to completely avoid flaring at all. His intent was to create a beautiful and interesting look that is future-proof for ultra high definition and high dynamic range television, where optical imperfections are enhanced by a factor of 10 and can be incredibly distracting.

At the same time, he made it easy to introduce creative unpredictability into an otherwise near-perfect and already-beautiful image. The rear magnetic holder simplifies the attachment of nets and optical elements to the rear of the lens, making it easy to draw out the classic qualities of the lenses.

As you can see above, the base look is very attractive. Our model’s skin is smooth and beautiful. At the same time, the lens isn’t soft: fine detail is preserved, but it’s not accentuated or over-enhanced. Also, telecentric bokeh is very smooth, and backgrounds often feel as if one is looking through a rainy window.

Speaking of backgrounds, we’re looking at a bookcase and a coat rack draped with light bulbs. Remember the angle of the books. That will be important later.

Camera assistant Ambar Capoor uses his expertise at reducing flares to create them instead.

Let’s look at some actual nets.


Fine black tule.

One of the first nets I tried on the back of a Signature Prime was classic Christian Dior #5 pantyhose, used by film cinematographers for decades. At the time I felt it photographed too strongly, so I chose to test a variation of my old broadcast go-to, bobbinet.

Fine black tule has a definite smoothing quality. It reduces resolution and conceals skin imperfections while showing very little impact on the out-of-focus areas of the image. Anything placed very close to the front or rear of the lens tends to add texture to the out-of-focus portions of the image, so one should always choose diffusion materials and filters with these effects in mind. Soft backgrounds are the stage against which we set the action of a scene, and their quality is often as important as the subjects we photograph against them.

No net.
Fine black tule.

This is a subtle version of the Christian Dior #5 effect. It’s very flattering, but it is not a look one sees much anymore. You’ll see this look in a lot on feature film closeups from the 1940s, 1950s, and 1960s.

The net image is a little warmer than the image without the net. This is likely due to the net fabric spreading the warm light from the lightbulbs visible in the background.

Fine black tule.

I’m told that the pattern of the net appearing in out-of-focus highlights has something to do with the wave nature of light. This effect occurs whenever we shoot through a filter or fabric that has a pattern to it.

Fine black tule.

This blurry image shows books leaning on a shelf in the background. They aren’t important now, but after I change filters they will become very interesting indeed. Let’s do that now.


Black sparkle mesh.

This show a subtler version of the fine black tule effect, but this net does some different things to the background. Let’s look at our model’s face first.

No net.
Black sparkle mesh.

This net imparts a slight haze reminiscent of spherical aberration. It’s subtle, and I’m a huge fan of subtle. This is an effect that the audience will feel without consciously recognizing.

Once again, the netted image is warmer due to the shiny fabric catching and spreading the light from the bulbs in the background.

This next bit is the interesting part.

Black sparkle mesh.

Notice how background textures look like brushstrokes? There’s a highlight at the bottom left that reveals the pattern of the mesh, but the out-of-focus bookshelves feel as if they’ve been painted in. The effect is even stronger on the other side of the frame.

Black sparkle mesh.

My theory is that the holes in the fabric become virtual apertures that bring background textures into focus. I saw something similar a while back when comparing bokeh characteristics between wildly different types of lenses: ARRI Zeiss Master Primes and Cooke S4s.

ARRI Zeiss Master Prime.
Cooke S4.

Master Primes have fairly round irises, while Cooke S4 irises have an octagonal scalloped shape at wider T-stops. This has a fascinating effect on bokeh.

ARRI Zeiss Master Prime.

I see some structure to the out-of-focus wires that run between the lights, but it’s fairly soft.

Cooke S4.

I see the wire structure more clearly here. Wherever a wire lines up with one of the hard iris edges, it becomes sharper.

My suspicion is that black sparkle mesh subtly enhances background textures that line up with the coarse patterns within the net. This includes books, hair, shelves… anything that’s a hard line with some inherent contrast.

Let’s take a look at one more net.


Silver Sparkle Mesh.

This image is much warmer than the others, and I assume this is because the silver net material is doing the best job of spreading the warm light from the background across the frame. I see the same brushstroke patterns in the background that I saw in the black version of this same material.

No net.
Silver sparkle mesh.

The diffusion effect is quite strong. This is the lightest and shiniest fabric, so it’s throwing light everywhere.

Silver sparkle mesh.
Silver sparkle mesh.

Once again, the texture of the net enhances background textures that align with portions of its mesh.

What I love most about this fabric is the quality of the lens flares it creates.

Silver sparkle mesh.

If one finds just the right spot, one can create veiling glare that reveals the pattern of the net.

If one directs light into the lens, the effect is very different.

Silver sparkle mesh.

I originally noticed this effect while photographing this same model for the ARRI Mini LF launch event in Burbank. I happened to pan past a backlight with this particular net in place, and suddenly I felt as if I was underwater, staring up at rays of sunlight.

As I panned the camera left and right, the texture of the rays changed. It was absolutely fascinating. I’m afraid to say that I played around this this net for way too long. (At the time, I didn’t test this effect with the black sparkle mesh. I’ve since performed the same test, and it shows the same effect, only with much more subtlety.)


Rear nets have fallen out of favor over the last decade or two, but as cinematographers search for new ways to capture the unpredictability of film in digital imagery, old-school tricks like this may find new life.

In the 1990s, the same DP who invented the I-ring created another product called LightBreaks. They were clear, heat-resistant sheets printed with black patterns and textures, to take the place of the traditional wood cucaloris. The first time he showed them to me I shied away from the more recognizable patterns, such as thunderbolts, assuming they would be too hokey. “Trust me,” he said. “Give them a try.” Sure enough, the thunderbolt pattern looked great, and in practice the shadows it cast didn’t look much like thunderbolts at all. It became one of my go-to patterns. (Here’s an example from the old Lightbreaks website, circa 2003.)

To me, a fine repeating pattern is less interesting to me than the organic, semi-random, curvy weave of the sparkle mesh fabrics. The rear magnetic holder on the Signature Primes makes it dead easy to quickly cycle through a number of fabrics that may not look right by eye, but may produce amazing and unpredictable results when placed behind a lens. Sometimes the option that looks the strangest can yield the most interesting results. The only way to know is to try.


We’ve been experimenting with placing optical elements into our rear magnetic holders. It’s dead simple to take one of these holders to an optometrist and have custom diopters made. During a recent third-party test with a variety of different custom diopter elements, we found that we could match the looks of a number of vintage lenses with a consistency never seen before.

This will only become more interesting.

Art Adams is Cinema Lens Specialist at ARRI, Inc. You can reach him here.

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Art Adams is a cinema lens specialist at ARRI, Inc. Before that, he was a freelance cinematographer for 26 years. You can see his work at http://www.artadamsdp.com. Art has been published in HD Video Pro,…