Review: Aputure Accent B7c cinema grade light bulb

Aputure recently released the Accent B7c, a mains power and battery operated 7W RGBWW colour-mixing LED light bulb. It’s the first product in the new Accent family of LED lights built for filmmakers. The B7c features a standard E26/27 fixture but unlike typical household LED bulbs, the lamp uses cinema grade LEDs to reproduce skin tones with CRI and TLCI values of 95+ and a tungsten SSI score of 85.

Aputure claims the B7c bulb can produce over 90% of the saturated colours in the Rec.2020 colour space, a claim I couldn’t verify, but if it holds, it puts the bulb on par with industry-standard lighting instruments.

Unique for a bulb that fits ordinary lamp shades, the B7c features 20KHz step-less dimming that remains completely flicker-free up to at least 1,000fps with no colour shift. With a frame rate of 240fps, there was not a flicker to be seen while the colour indeed remained the same throughout.

That the Accent B7c is not like any ordinary light bulb is apparent from its ability to match the colour temperature range of the Nova P300c, Aputure’s most advanced colour mixing light, producing a wide colour temperature range of 2,000K-10,000K.

Measuring at 100% output & 40 cm distance Lamp setting Light meter value
All temperatures are in degrees Kelvin 3200K 3020K
Lamp settings are set in the Sidus 4000K 3810K
app used to control the lamp 5600K 5050K
6000K 5300K
7000K 5850K
10,000K 7500K

I will let you be the judge of how accurate the lamp is from the figures in the table above. The measurements were taken with a Lumu Power Pro Gen.2, a light sensor that has been developed specifically for LED lighting attached to an iPad Air 2.

When combined with the Sidus app’s SourceMatch feature, it can match nearly any white light source. That is certainly true when visually observing the lamp’s colour temperature next to the ‘original’ and the measured values confirmed my visual assessment:

Source: LED lamp 12W at 100% measured as 2590K

Match value: B7c at 100% measured as 2720K with a -1/10 magenta shift.

While I found the strict colour temperatures to be a bit off, the matching feature was very accurate and for a lamp like the B7c the latter is more important than the former. The colour temperatures by themselves aren’t that important as you will probably have a light meter at your disposal with which you can set the temperature on a continuous scale from its 2000K low to its 10,000K high.

The B7c is the first bulb designed for filmmakers that has a built-in battery, powering the B7c for over 70 minutes at full power, and over 20 hours as it approaches minimum brightness. In AC power mode (grid power) the B7c retains its last settings and turns on and off like a traditional light bulb, allowing for natural interactions with actors. In DC operation, the lamp is meant to be used more like an off-camera light source.

To operate the bulb off the grid (DC), you need to first turn it on with the tiny On/Off switch on its side. What I did notice and isn’t stated anywhere in the Quick Start guide or on the website as far as I know, was that you need to hold the power switch down a good four seconds before the B7c will turn on. Turning off happens instantly after pressing that button.

With only the switches to work with, e.g. when you don’t have access to the app, the brightness and CCT can be increased/decreased using the two outer buttons.

The B7c doesn’t look like an ordinary light bulb in that uses an aluminium structure and a toroidal diffusion design, with the diffusor the smallest part of the lamp. Yet, the B7c spreads lights evenly as ordinary light bulbs for use inside lamp shades.

Finally, when you use the Sidus Link app, the Accent B7c has access to its built-in lighting FX mode as well as SidusPro FX. Furthermore, using your iOS device’s camera, the Sidus app will let you pick any colour (not just from other lamps) and will set the lamp to the closest colour it can output. That feature worked very well and the output intensity, hue and saturation are even customisable. Another FX capability lets you cycle the lamp in all kinds of configurations between two white colour temperatures and intensities.

Yet another one that I found fascinating is the Picker FX effect where you record a number of colours, e.g. from a colour patch deck like Pantone’s, and let the B7C play the colours back as you recorded them with the iOs device camera.

The Accent B7c retails at €74 but soon they will be available in a configuration of eight lamps inside a robust carry case with built-in charging power.

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