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PLM umbrellas offer sweet combo of efficiency and softness
Thursday, December 17, 2009 | by Rob Galbraith
What has the brightness of a sport reflector, the softness of a large softbox and is quick to set up and tear down on location? It's the Parabolic Light Modification (PLM) system from Paul C. Buff. Available in three sizes, the silver version of these clever, inexpensive umbrellas from the Nashville, Tennessee-based lighting maker are like no other portable strobe modifier we've ever used, combining incredible light efficiency with wraparound light smoothness. If you want your medium power monolights to think they're big power packs, or make your shoe mount strobes put out soft light that's still usably bright, read on.

Forever Young: Canon EOS 5D Mark II + EF 70-200mm f/4L IS at 200mm. Main light (coming from right) is an AlienBees B1600 + PLM 64" Silver umbrella + 1/2 CTO gel (Photo by Rob Galbraith/Little Guy Media)

The Paul C. Buff PLM system

Introduced earlier this fall, the Paul C. Buff PLM system consists of three umbrella sizes:
  • 86" PLM A huge umbrella, this size has an arc dimension of about 86 inches (218cm) and measures about 75 inches (191cm) across the umbrella opening. Collapsed and in its carrying sleeve, length is just under 44 inches (112cm).

  • 64" PLM Still darned big, this size has an arc dimension of about 64 inches (163cm) and measures about 55 inches (140cm) across the umbrella opening. Collapsed and in its carrying sleeve, length is just under 34 inches (86cm).

  • 42" PLM Rounding out the lineup, this size has an arc dimension of about 42 inches (107cm) and measures about 39 inches (99cm) across the umbrella opening. Collapsed and in its carrying sleeve, length is just under 23 inches (58cm).
Glossy and Matte: Silver and white surface PLM system umbrellas from Paul C. Buff (Photo courtesy Paul C. Buff)
All three are available in either silver or white internal surfaces. The silver features a 16-rib design and parabolic shape designed to project the light forward with the efficiency and coverage of a narrowish angle reflector, but with the softness of a large softbox. The design and shape of the white versions are identical, but they have a noticeably wider light dispersion pattern than their silver counterparts, and they're not as efficient.

The silver surface versions are the ones that offer the magic mix of brightness and smoothness we're digging so much, though there is one configuration of the white surface version that is also quite useful. More on that later in the article.

Three optional diffusers and covers allow for alternate configurations, including:
  • Front Diffusion Fabric With this white diffuser material attached to the front of a silver PLM umbrella, it takes on the characteristics of an extremely efficient wide dispersion softbox. It can be attached to a white PLM too, in conjunction with the Black Outer Cover Fabric, to create a more typical, moderately efficient softbox.

  • Black Outer Cover Fabric For attachment to a white PLM when the umbrella is to be used in bounce (rather than shoot-through) mode.

  • Black Front Spill-Kill Fabric For use on a white PLM in shoot-through mode to create a Japanese Lantern-style extra wide coverage light source.
Accessorize: From left to right, Front Diffusion Fabric on a silver PLM umbrella, Black Outer Cover Fabric and Black Front Spill-Kill Fabric on white PLM umbrellas (Photos courtesy Paul C. Buff)

Since August 2009 we've been using a mix of the 86" PLM and 64" PLM, both silver and white, plus all three of the fabric accessories. Our interest in the new umbrella series stemmed from a desire to shoot outdoor team photos with a smaller cartload of lighting equipment than in the past. With the Photoflex umbrellas that myself and shooting partner David Moll had been using previously, it was necessary to set up three and sometimes four 2000ws packs and heads such that big teams, like football, could be lit to match or overcome ambient sunlight with minimal falloff from front to back.

That translates into a lot of gear to push out into the field, plus the occasional tripped circuit breaker too. Or it meant not using light diffusers of any kind, in favour of reflectors that produce bright but hard light.

The PLM system and team photos

Enter the PLM system. In testing before the first outdoor team photo shoot of the new season (football), we found that three AlienBees B1600 640ws lights in three PLM 64" Silver umbrellas could deliver between f/9 and f/10 at ISO 100 from roughly 40-45ft (12.2 - 13.7m) away, and do so with no more than a 1/3 stop variation in brightness across the entire width of the area that the team would occupy.

Field Level: Three AlienBees B1600 640ws monolights aimed at PLM 64" Silver umbrellas. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

This was over two stops brighter than what we'd been able to squeeze out of umbrellas previously at this location, at least from ones that could also provide sufficiently smooth, even coverage to make them a better option than harsh reflectors. The trio's output was also bright enough to hit the exposure settings we needed, including in full sun. The goal was to have the big light in the sky, if it was out that day, be at most a high-angle sidelight. That works out to an aperture of f/9 or smaller at ISO 100.

On shoot day it was sunny with a light haze. We started by setting up the lights and umbrellas the same as the dry run several days earlier. With the team in place in rows on a grass covered hill (this team is too big for any of the available outdoor bleacher options), we could see one problem had cropped up: there was too much falloff from the front row (f/10) to the back (f/6.3).

To solve this, we took advantage of the focused beam characteristic of the PLM 64" Silvers, adjusting their tilt upwards progressively while taking light meter measurements until the front to back readings were within 4/10 stop (with a bit more time we perhaps could have trimmed that down to 1/3 stop). Feathering the light from the foreground to the background like this isn't really possible with typical wide dispersion umbrellas, at least not from a distance.

The result was an exposure that was right on the money: 1/320 at f/9 at ISO 100 on a Nikon D3X. The final photo is below. Note that no selective toning adjustments have been made to correct for uneven brightness. Also note that because of the makeshift arrangement of the team on the grassy slope, the front-to-back distance is greater than what you'd normally get if the same team posed on risers.

Seeing Red: A football team photo lit by three AlienBees B1600 640ws monolights in three PLM 64" Silver umbrellas. Nikon D3X + AF-S NIKKOR 50mm f/1.4G. Click photo to enlarge. Click here to download a higher-resolution version (Photo by Rob Galbraith/Little Guy Media)

Here's another glimpse at our outdoor studio, plus an example of what the players would look like if the flashes weren't lighting things up.

Behind the Scenes: Another view of the football team lighting setup. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

Lights Out: Without the benefit of flash the light gets ugly (Photo by Rob Galbraith/Little Guy Media)

The other thing we noticed during the football team session was that even with the PLM 64" Silver umbrellas positioned well away from the team, the light was still pleasingly soft; with only one light firing at a time during setup, the shadows cast were surprisingly smooth-edged and softbox-like. As we were starting to figure out, the silver surface PLMs lay waste to the notion that silver light modifiers are automatically hard light sources. They can be, if they're small, or in the case of umbrellas, if they're an inferior design. Not so the PLM 64" Silver, and the PLM 86" Silver produces even softer light still.

All subsequent outdoor team photos this fall were lit with the same formula: three AlienBees B1600 640ws monolights and three PLM 64" Silver umbrellas, positioned for even lighting across the entire team. Whether frontlit, backlit or sidelit by the sun, this kit has been able to match or overcome the ambient light each time. For smaller teams the lights have been turned down to 320-500ws, since full power was pushing the aperture beyond our preferred f/9-f/11 target range, to as small as f/14.

An example of the lights overpowering direct sunlight is below. (One additional example is the soccer team photo in a previous article.)

Fill Flash: Nikon D3X + AF-S NIKKOR 50mm f/1.4G. Click photo to enlarge. Click here to download a higher-resolution version (Photo by Rob Galbraith/Little Guy Media)

With a setup like the football team photo, careful aiming of the umbrellas is critical to ensure even brightness from the first row to the eighth. For all other outdoor team photos, comprised of teams with fewer players and shorter front-to-back distances than football, it has been easier than expected to achieve even lighting across all players, given the focused beam nature of the silver PLMs. With the centre umbrella pointed at the centre of the team, and the outer two umbrellas pointed towards the left and right sections of the team, respectively, evenness has just happened, without any additional aiming effort.

The lighting approach was modified slightly for indoor team photos. The setup used the same trio of AlienBees monolights and the same PLM 64" Silver umbrellas, but now with the Front Diffusion Fabric attached. This turns the silver PLM umbrellas into large high output circular softboxes.

The intention had been to go with the PLM 64" Silvers without diffusion. But indoors, at least in one particular gym, their non-wide light dispersion pattern was keeping too much light off a far background that needed brightening. It was decided the simplest solution was to spread out the light coming from the umbrellas.

Almost Ready: The team's view, left, and an AlienBees B1600 + PLM 64" Silver with Front Diffusion Fabric attached, right. Click either photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

Using the Front Diffusion Fabric drops the PLM 64" Silver's output by just under two stops. For indoor photos this wasn't a problem, since we didn't have sunlight to contend with. And in any event, the combination of PLM 64" Silver plus Front Diffusion Fabric is still nearly a half-stop brighter and noticeably softer than the umbrella we'd used previously, the Photoflex 60" White (convertible model). An example photo is below. (The hairlight is an additional flash mounted high and behind.)

Diffused Dinos: Canon EOS 5D Mark II + EF 50mm f/1.4. Click photo to enlarge. Click here to download a higher-resolution version (Photo by Rob Galbraith/Little Guy Media)

Continued on the next page....
Next Page: Comparing softness, brightness and light cast
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