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Flex Light Review and Photometrics

A comparison test with Westcott’s flexible LED panel

Recently I had the pleasure of working on a project with Jem Schofield. Jem has a gear obsession that borders on a medical condition, and I was delighted to see that he brought along a set of Westcott Flex lights.

Working with the Flex light, I was surprised at their relatively powerful output and clean color performance…color accuracy and output power are often weak points for LED lighting fixtures, and these new lights didn’t seem to suffer from those issues. I’m always on the lookout for tools that are lighter and smaller for travel documentary and interview work, so I decided to do some lighting tests to see if they were powerful enough.

I chose to test Flex with a Kinoflo Diva 401, a commonly used interview lighting kit. The Diva kit is fairly easy to travel with, has low amp draw and very respectable output for a fluorescent fixture. It’s also easy to use…simply aim it at your subject, pop on the Flozier diffuser, and shoot. With the barn doors fully open on a Diva, you can almost get a 24×36 sized soft source. In contrast, the Flex is a 10-inch square panel. While it may seem odd to compare an inherently soft fluorescent fixture to a hard source LED, I wanted to see if I could reasonably swap out a two-light Diva light kit in a talking-head interview setting and use a couple Flex panels with diffusion or bounce instead.

Review TL;DR

I found that a single daylight Westcott Flex light panel has slightly less output than a Kino Diva 401 (2ft 4-bank, daylight bulbs). To my eye, Flex lights don’t appear to have the green spike color issue seen in cheap LED panels. Westcott says the daylight Flex panel rates at 95 CRI (their tungsten panel is 98 CRI). In my testing I found that Flex lights do not shift color when dimming, a known issue with the Diva light (and many others).

The Diva is a softer light source by design. You will of course have to work a little harder to diffuse and spread a 10″ Flex light to accomplish the same soft quality that a 4-bulb Diva Lite emits. But once diffused and spread, the Flex performs close to the output of a Diva. Optimally, two ganged-up Flex lights into a frame would be a nice Diva replacement, with similar amp draw and more light output. 

The Diva 401 features 4x 55w CFL tubes that can be swapped between daylight and tungsten, and a typical fixture draws 2.0 amps. Wescott says that Flex is a 55w fixture, and the included DC power adapter is rated at a 1.5amp draw. Flex light color temperature cannot be changed, you either choose a daylight or tungsten panel. In my testing, I found that the daylight panel doesn’t convert well with a CTO gel, so you may need both models in some scenarios.

Flex lights do not come with barn doors, so controlling spill can be a challenge at times. But if you already work with diffusion frames or bounced sources, Flex could be a good fit for you. And it looks to be a great choice for process trailer and for travel work, thanks to its small size and power efficiency. That’s where Flex really shines…where space, weight, and power is at a premium.

You will find a table of photometrics below with lux, footcandle, and stop metering for each light, as well as framegrabs and color examples.

What is a Flex light?

Westcott Flex lights are a thin, flexible pad of LEDs. The panel itself consists of 256 LEDs embedded in a 16×16 grid on a flexible 10-inch square pad that is backed with a tough black fabric. They appear to be sealed into the soft white panel. Westcott offers both daylight and tungsten options of the Flex panels. They are flexible enough to be rolled into a tight tube, water-resistant, dimmable, and rated at 55 watts each. Flex panels are also affordable, at $699 for a kit with diffusor and mounting frame (if you can actually find them in stock anywhere). Flex lights are a little smaller than a Litepanel 1×1 fixture. They have punchier output and better rated color than a comparable Lightpanel; a daylight Flex panel is 95 CRI vs the 90 CRI 1×1 Lite panels. It’s also worth noting that Westcott rates their tungsten Flex panel at 98 CRI (though it has slightly less power).

First Impressions

Flex lights are flexible! You could wrap a Flex around the inside of a practical lampshade, gaff tape it under a kitchen cabinet or to the headliner of a vehicle, hide it behind an audio monitor on a stage performance…the possibilities are tantalizing. The pads emit very little heat to the touch, and are completely silent. The size of the fixture is quite attractive for travel work…you could probably squeeze half a dozen or more of these panels into a Pelican 1510, including all the cables and mounting frames. That’s pretty amazing.

Weight of the LED panel itself is 8oz, and the entire kit with panel, frame, extension cord, and power adapters comes to 2lb 10oz. The back of the panel has an integrated power cord pigtail with a robust strain relief where it connects to the pad. Each corner of the panel has a strip of velcro, this would be an excellent flush-mount solution for tight locations. The kit comes with a lightweight X-frame support, this has tabs that slip under each velcro corner, stretching the LED pad taut and holding it securely. On the back side of those arms are flip-out accessory holders, this is what you mount the diffuser onto.

Velcro could also make it simple to gang multiple Flexes into a single large source, or for installations where you need lighting integration in the walls. I recall a commercial shoot last fall for director Jesse Rosten where a few Flex panels could have solved a lighting issue. We had a large interior kitchen space to work with, but the particular spot in the kitchen that ended up being used was hemmed in by appliances and cabinets. We needed a large, soft front key light in an area didn’t give me much room to work. The simplest solution would have been a small fixture into a frame with light diffusion…and I had room for the frame but not much room behind it for the light fixture.

If we had a few Flex lights on the grip truck, I would have simply ganged them into a large flat source on a card, and hung that over the side of one of the appliances. That would have been the quickest solution. Sarge, my clever gaffer, solved the problem by bouncing a ceiling-mounted, tightly-snooted Jo-Leko HMI from across the room into a curved showcard. It ended up looking great. However, this would not have been possible had we ever needed to cross the light, or had we been using haze in the room (you would have seen the shaft of light). In that scenario, a Flex would have been a good fit.

Power and Mounting

Something I noticed immediately is Westcott’s less-than-desirable power solution; an AC power cable that leads to a DC adapter, that leads to a dimmer control, that leads to the light. It’s a little too convoluted, and in my opinion that is too many cords and connectors to lose or break. This is probably the biggest weak point in the system, from my perspective. At least they gave us locking screw connectors for the power cables, so they don’t pull out when hanging.

The dimmer control also turns the light on and off, so there is no way to set the power and then turn the light off…on/off should be a separate control from the dimmer. Are you listening, Westcott? The cables are reasonably robust feeling for something this small, so that’s nice. The cord from the AC/DC adapter to the dimmer module is a single plug, and the cord from dimmer to the light is a keyed 4-pin plug. The 16ft extension cord fits between the dimmer and fixture, and everything is supposed to be “water resistant” according to Westcott. 

Another annoyance was the mounting system for the support frame. The back of the frame has a lightweight ball head attached with a wingnut, and then a lightweight metal clamp attached to that. That’s it. No 3/8 thread or 5/8 spud, no 1/4″ screw threads to mount to, just a clamp. While this clamp might be useful in certain scenarios, and you can clamp onto it with a grip head, I intend to modify my lights to fit directly onto a light stand spud. With a 5/8″ reciever, I can put Flex on a stand, a mafer clamp, whatever. The included ballhead is also pretty weak sauce, I’ve nearly stripped the head off the locking screw already. Both of these will be going away soon. Jem Schofield had already modified his Flex lights with a small ballhead and a Nano clamp setup, and in that configuration they were very easy to work with.

Finally, there are currently no barn door options for the Flex light. This makes spill a bit of an issue, something that I’ve been solving with blackwrap for the time being. I will be looking into small softboxes (with a removeable diffusion panel) that could clip onto the Flex and help control spill. Specifically a mini softbox that is lightweight and would still be able to fold flat for travel, that would be an optimal solution. And a small softbox would allow you to easily grid the light if needed. I think that’s the missing piece in this kit. I’ve been told that the Airbox inflatable 1×1 softboxes would work on a Flex panel, but have yet to test that combo.

I anticipate that Westcott will hear this criticism from other shooters as well, perhaps they are already working on more robust power and mounting solutions. For power, we really need an option that combines the AC adapter and dimmer control into one small unit. Another option that would be useful is an adapter cable that terminates in a D-tap, so lights can be run from a battery. For anyone looking to DIY their own power solution, the stock AC adapter draws 1.5amp 110/240VAC and outputs 15v, 4amp to the dimmer module.

Comparison Testing

A typical complaint with the Diva Lite is that it noticeably shifts color when dimming. To my eye, Diva fixtures always look slightly magenta tinged at full power, and then shift to a more obvious magenta cast when dimmed. So I generally add a 1/4 +green gel at full power, and a 1/2 +green when dimmed to 50% and below. For this test, we used a 1/2 + green for all the Diva setups. In the first setup, we used a Sekonic 758cine to meter output from each light both open-face and with each fixture diffusion accessory. Obviously this setup would not be an optimal soft key light for an interview…just getting a baseline for each light.

For the second setup, we punched each light through a medium diffusion gel, Lee 250 Half White. Light output was metered both open-face and also with the stock diffusion attached to the light. Open-face through Lee 250 was useable as an interview key, but still slightly sourcey in the case of the Flex. Adding the stock diffusor before it got to the 250 diffusion helped improve the spread of each light, and resulted in a decent soft light key source, though the Diva source lent a softer quality, given it’s size. Also, the Diva’s 1-stop Full Flozier is a thicker diffusion than Westcott’s 1/4-stop diffuser, so the comparison in diffused power output is slightly skewed in Flex’s favor.

The third setup was a bounce configuration, pushing the the light open-face into a 4ft white beadboard (my $20 DIY reflector from Lowe’s). This was the most flattering soft light setup we tested, and also one of the most efficient at delivering a lot of soft, wrapping light. Remember, the size of a light source relative to subject size is what dictates softness, so creating a 4-foot square source out of each light was very effective. In this configuration, the Flex performed very close to the Diva in terms of metered output. This type of setup does a great job of spreading the light from that tiny 10×10 pad. Side note: the Diva light we tested actually performed slightly better than KinoFlo’s photometrics, by about 500lux on the open-face test.

Photometrics

Open face at 1-meter

Flex – 180fc / 1900lux
f/11 @ 24fps, 800 ISO
Notes: open-face

Flex – 120fc / 1300lux
f/8,4 @ 24fps, 800 ISO
Notes: Wescott diffusor

Diva – 270fc / 3000lux
f/11,5 @ 24fps, 800 ISO
Notes: open-face, no gel

Diva – 190fc / 1200lux
f/8,3 @ 24fps, 800 ISO
Notes: Flozier Full diffusor, 1/2 +green

Through Lee 250 Half White diffusion (Light 1/2m from diffusion, Sekonic reading taken 1m on other side of diff)

Flex – 60fc / 600lux
f/5.6,3 @ 24fps, 800 ISO
Notes: open-face

Flex – 40fc / 420lux
f/4,8 @ 24fps, 800 ISO
Notes: Wescott diffusor

Diva – 70fc / 740lux
f/5.6,6 @ 24fps, 800 ISO
Notes: open-face, 1/2 +green

Diva – 37fc / 400lux
f/4,7 @ 24fps, 800 ISO
Notes: Flozier diffusor, 1/2 +green

Off 4×4 beadboard bounce (Light 2.5ft from bounce, Sekonic reading taken 4ft from bounce)

Flex – 52fc / 560lux
f/5.6,2 @ 24fps, 800 ISO
Notes: open-face

Diva – 60fc / 600lux
f/5.6,3 @ 24fps, 800 ISO
Notes: open-face, 1/2 +green

Misc Notes – Flex open face at 4ft, 6ft, and 10ft

Flex – 150fc / 1600lux
f/8,7 @ 24fps, 800 ISO
Notes: 4ft, open-face

Flex – 70fc / 700lux
f/5.6,5 @ 24fps, 800 ISO
Notes: 6ft, open-face

Flex – 26fc / 280lux
f/4,2 @ 24fps, 800 ISO
Notes: 10ft, open-face

Misc Notes – 350w tungsten for comparison at 4ft, 6ft, and 10ft (ARRI’s photometrics)

ARRI 350 – 274fc / 2949lux
f/13 @ 24fps, 800 ISO
Notes: 4ft, fresnel flood

ARRI 350 – 121fc / 1302lux
f/9 @ 24fps, 800 ISO
Notes: 6ft, fresnel flood

ARRI 350 – 45fc / 484lux
f/5.6 @ 24fps, 800 ISO
Notes: 10ft, fresnel flood

Color shift while dimming

For the final comparison, we filmed a subject and a Spydercheckr color chart with each light at both full power and half-power. This was to see how well the Flex compared to the Diva in terms of color, and also how the color of each light shifted when dimmed. We used a Sony FS700, 50mm Zeiss CP.2 and Odyssey 7Q recorder. On the Odyssey we captured 4K-RAW to 4K-ProresHQ.

In the video embedded below you will find side-by-sides from each light showing untouched shots, shots with a basic contrast curve, and shots with Resolve’s Color Match applied. The Resolve chart match feature is pretty much automatic, though it crunches contrast beyond what I personally would use on a shot like this…I would definately dial out some contrast in the grade. But as you can see, the colors can be made to match without much work. 

As with the photometric tests, the Diva was fitted with a 1/2 plus green gel. In retrospect, I probably should have used a 1/4 +green for the undimmed setup, you may notice the Diva is a touch too green on that particular shot. However, it does illustrate the practical annoyance of working with the Diva’s color issues. 

Reviewing this footage, the Flex light looks a touch warm to me. It’s hard to see that without a side-by-side comparison, but there is definately more red in the Flex shots than you can see in the Diva skintones. Looking at a vectorscope verifies this, more red saturation and just a hint more yellow saturation in skintones under the Flex light. It’s not really a major issue, just something to be aware of.

A side note on color…we also did a quick test and gelled the daylight Flex panel with a full CTO to see how it converts to tungsten. The result was not optimal, ending up with more of a theatrical look with an overall orange color cast that did not seem to white balance out cleanly. If you will be matching other tungsten sources on a regular basis, I recommend getting the tungsten versions of Flex instead of daylight (or carry both options in your kit). 

Finally, here are raw and quick-graded framegrabs from a recent interview shoot. This is a simple key setup, with a single daylight Flex light punched into a 4×4 white beadboard, positioned roughly 4ft feet from subject. At full power I was able to shoot at f/4.0, 640 ISO, 24fps. Camera white balance was set to the Daylight preset. As you can see, the color looks clean overall and I was able to get a pleasing soft light out of this tiny fixture. And I still had some room to work, we could have walked the bounce in a touch to soften contrast and wrap the shadow side a bit more. (click for full-resolution image).

Conclusions

The Flex light is a relatively powerful, lightweight fixture that is well-suited to interior work on modern cameras. Light output and color performance is quite good for an LED panel, and they are priced competitively. Flex seems to lean a touch warm on color, but not objectionably so. The existing Flex power solution is annoying, and the current subpar standard mounting system will likely require user modification. The lack of barn doors means you’ll also have to find a way to control side spill, potentially adding cost to the kit. These are all areas that Wescott could greatly improve. However, Flex lights are lightweight enough to be taped and velcroed anywhere, making them useful out of the box in a variety of unique shooting scenarios.

I personally like that Flex is a very low-amp hard source that also has enough punch to work as a soft source when modified. If you are the type of shooter who simply wants to clip a diffuser onto the front of a large soft source and shoot, the Flex is probably not right for you. It requires a little more work to create a soft-light setup. However, if you regularly use frames and bounce light, the Flex may be a good fit for your shooting style. Particularly if you do a lot of travel shooting. I’m imagining a lightweight traveling kit with a few Flex panels, a 42″ Nori Squarebounce white reflector, Matthews Road Rags & MiniGrip, and Manfrotto Nano stands. That would be a tiny lighting kit footprint!

Finally, the possibilities for narrative work are very exciting. From process trailer work to interior tight spaces, every grip truck should have a few of these in the kit! For me, I intend to purchase additional Flex lights in the coming months to be used for upcoming lightweight travel and documentary work.

Many thanks to Karson Holbrook for helping out with these tests.


Matt Jeppsen is a working DP with over a decade of experience in commercials, music videos, and documentary films. Editorial ethics statement can be found here, and you will find a cinematography reel and contact info at mattjeppsen.com

 

 


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Matt Jeppsen is a working DP with over a decade of experience in commercials, music videos, and documentary films. You can view Matt's cinematography reel and contact info at www.mattjeppsen.com

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