It’s Time: Sharpen Your Diffusion!
Newer filters, like this Tiffen Black Satin can improve images substantially on many of today's cameras.
Evaluating the images from 4K cameras like the BlackMagic URSA, AJA Cion, and morass of DSLR variants, the need is glaring for a more finished less brash look, whether shooting a feature film, regional commercial, or the network news.
It’s not just the very high resolution sensors that are producing more clinical looking images today: it’s also the razor-sharp lenses coupled with a camera’s more sophisticated processing and HDR.
It used to be when it came to diffusion that one size fit all. Twenty-five years ago TV professionals understood that a Tiffen Black Pro Mist could work wonders on analog Betacam cameras to impart a more organic look and help break down the hard plastic video edge around in-focus objects.. This understanding was so pervasive that many camera rental houses included a ½ BPM filter with their basic kits much as they would include a lens shade or cleaning tissue.
Figure 3) Older diffusion filters like the Black Pro Mist wreak havoc with 4K sensors fitted with deep photosites. The broad scatter from vintage filters, including Fogs and Double Fogs, produces an ugly unusable image now.
Today a much different understanding is required to derive the best possible images from large-format single-sensor cameras like the Sony A7 and BlackMagic URSA. Given the high density deeply recessed photosites of modern sensors, the large dot pattern and broad scatter of vintage filters like the Black Pro Mist, Soft F/X, Fogs and Double Fogs, now produce an ugly unusable image (although the BPM in the lightest grade may still prove useful to match various type lenses, a newer series Zeiss CP.2 prime to a vintage Cooke zoom, for example).
Figure 1a) For shooters working with inexpensive 4K single sensor cameras like the BlackMagic URSA, Tiffen’s newer sharper diffusion filters – the Satins, Black Satins, and Pearlescents - will improve performance substantially by reducing noise, improving shadow and highlight integrity, and producing in general a more flattering image.
Which brings up a crucial point. Today the savvy broadcast shooter understands that changing a camera and lens combination may also mean selecting a new filter type or grade to ensure the desired texture and character of images. This might be done also for consistency to maintain the signature look of a program or talent. A daily soap opera over many years typically has an identifiable look, and most broadcasters will want to preserve that look both for the brand and to communicate the desired genre and tone.
This is where the choice of a diffusion or finishing filter comes into the picture. Fundamentally as camera professionals we all paint with light. And that light in almost every instance short of shooting with a pinhole camera must pass through glass.
So how that glass diffuses, scatters, and halates, the light ought to be of paramount concern to every professional camera person. This triangle of points – diffusion, scatter, and halation - enables filters to be produced that offer a wide range of looks and finishes. How much softening is appropriate? How much scatter? Which filter is best for your particular camera, lens, and resolution? It’s the one that best supports your visual story.
Now it has been the case in my years of experience that a crotchety engineer will object to any physical filter placed in front of the camera lens. Their reasoning is thus: A physical filter may degrade the image, and by baking in a look it reduces one’s options later.
The reasoning may be simple but it is also wrong. Baking in a look is not something to fear or avoid, but a storytelling tool to embrace. Someone, somewhere, at some point in the process must commit to a look. So it’s really about who is making that decision. To me, the choice of camera filter is just an extension of a professional's choice of optics to be made at the time of original image capture.
TELECENTRICITY OF NEW FILTERS
Lenses specific for digital use are designed to send light into a sensor’s photosite buckets in as straight a line as possible. This linearity is critical (certainly more so than when imaging on film) in order to produce clean unmuddied 4K images. The design of filters for digital applications must also therefore take the degree of light bending into account in order to preserve the telecentricity of the lens and its ability to reach deeply into the recessed photosites.
Beyond the refractive requirements the latest generation diffusion filters must also address the clinical look of most CMOS sensors.
Figure 2a) No filter.
Figure 2b) Tiffen’s Satin filters produce optimal results with no indication to the viewer that a diffusion filter has been applied. Images appear unmolested with a more integral feel and flattering finish. For non-fiction programs and documentaries the Satin/Black Satin filters may be used to great advantage without fear of producing an inappropriate theatrical look.
For documentaries and non-fiction programming, including shooting news talent and magazine-style shows, the Tiffen Satin and Black Satin filters in a light to medium grade are a superb choice.
Figure 4) Latest generation diffusion filters maintain sharpness in the eyes while tastefully slightly diffusing the edges of the eye sockets and skin in the face. The effect of these filters is very subtle. Compared to the normal Satin filter the Black Satin type produces firmer more pleasing shadows and a nice roll off in the highlights.
Introduced a few years ago these elegant filters reduce crispness and improve highlight rendering while being entirely unobtrusive, in fact, in most cases, only the camera person knows a filter is in use. Its very slight halation helps vintagize new sharp lenses, and the loss of resolution is subtle compared to, say, the Soft F/X which was designed for film and analog cameras twenty years ago. The Black Satin filter offers a comparable look to the normal Satin, with expanded shadow detail and less flare evident in the highlights. Simply put, the Black Satin produces results that are just straight out gorgeous.
Figure 5) The Tiffen Pearlescent offers a similar look to the Satins and other Glimmer Glass type filters but adds a slight glow to produce a more theatrical finish. While useful for narrative applications most non-fiction shooters will want stay with the more subtle Satin and Black Satin types.
For narrative work, movies, and commercials, Tiffen’s new Pearlescents offer a luxurious feel, maintaining a clean look overall while infusing a faint glow around highlights. When photographing women especially, the Pearlescent imparts a glamorous tone, which can help elevate one’s work above the sterile hard images that any shooter might be reasonably expected to achieve given a particular camera and lens combination.
It’s almost expected that significant picture defects will appear when shooting with an inexpensive camera in difficult low light or excessively bright conditions. But more often than not the appropriate camera filter can help mitigate the most deleterious effects of low-cost cameras employing relatively unsophisticated processing. In many cases the proper filter can make the difference between a professional-looking image and a blah lackluster approximation. This is because unlike a post-camera filter applied via software to the recorded file a physical camera filter impacts the sensor/lens/processor performance directly. A new sharper diffusion filter can significantly improve shadow integrity, reduce blocking errors, and soften the roll-off of highlights. The latter effect, how your camera handles the brightest highlights in a scene, is the most salient indicator of your professional work.
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