Review: SmallRig RM 40C mini LED video light

Friday 27 February 2026, 14:28 by Nando Harmsen | 3,423 views | 0 comments

This article was translated from Dutch with the help of AI. Read the original.

SmallRig has a small and compact 40-watt mini video light. It is an RGB LED panel that can be very useful for both videographers and photographers. I was given two to review.

Continuous light is needed for video. A compact but powerful light is preferable to a large and heavy one. Modern LED panels can produce a lot of light in a small package. The SmallRig RM 40C mini LED video light promises to be one of them.

A nice and neat LED panel with an output of 40W.
LED panels of this size can be cheap. I once bought a small set of Metz Mecalights for a few tens of euros. With four AA batteries, they produced one colour of light, and a yellow filter or diffuser could be attached with magnets.

The SmallRig RM 40C mini LED is in a completely different league. The small box, measuring 128 x 80 x 32 mm and weighing 302 grams, produces many times more light than those simple Metz Mecalights of yesteryear.

The RM 40C comes with a grid and a diffuser that attaches magnetically.

The SmallRig RM 40C mini LED video light

The RM 40C, as I will call this mini LED video light from now on, has 240 LEDs that together provide an output of 40 watts. This amounts to 4,670 lux at 1 metre at 5600K. It has a built-in 4800 mAh battery that provides 55 minutes at 100% output.

The white balance of the RM 40C can be set between 2500K and 10000K, with more than 36,000 available colours through hue and saturation settings. SmallRig guarantees a CRI of 96 and a TLCI of 99.

A small screen on top of the RM 40C shows the necessary information about the settings. These are the extremes of the colour temperature range that can be set.
In addition to the available colours, there are 14 built-in light effects for special effects. These can be set using the buttons and control dial. A small HD LCD screen shows the selected setting.

An overview of the various creative lighting programmes, aimed at effects for video recordings.
The RM 40C comes with a grid and diffuser that attach magnetically. There is a magnet on the back for 'hanging' the RM 40C on any metal surface. A 1/4"-20 thread is available for mounting it on, among other things, a tripod.

A standard tripod connection is provided. The unit also houses a magnet for positioning it on metal surfaces.
The light intensity can be adjusted continuously between 1% and 100% of the output. The unit has a large fan to dissipate heat. This cannot be adjusted manually, and automatically selects its speed.

Charging is done through a USB-C port with PD3.0 Fast Charging. The RM 40C can be used while charging. This prevents you from suddenly running out of power during use. This can be particularly inconvenient with video.

The side has the function button, on/off switch and USB-C PD connection.

A fan and the noise

The RM 40C has a fan of approximately 6 cm. The unit has ventilation openings all around it so that the airflow is optimal. The fan is not silent, however. At half a metre, the noise level is approximately 40 to 50 dBA.

Bear in mind that this is not a calibrated measurement, but it gives you an idea. Depending on the ambient noise, it can be picked up by a microphone during video recordings if the RM 40C is placed too close.

A large fan provides the necessary cooling. It is not silent, but it does not produce an excessive amount of noise either.
The unit gets warm during prolonged use, but not hot. The fan speed is variable. At an output of 50% or more, the fan runs at maximum speed.

Using the RM 40C

Using the RM 40C is easy. The buttons on the side are self-explanatory. Switch between the three functions, normal, RGB and effects, using the button on the side. Pressing the control dial then switches between the options in the selected function.

Setting it is easy with the clickable control dial. The functions can be switched using the button on the side.
Of the effects, switching between colours is very useful for video. The other effects are very specific. The normal light and RGB colours are also perfect for photography, especially macro.

For macro work, the RM 40C offers many possibilities. The 40 watts of light is more than enough. A 25-watt version is also available, which is slightly more compact. The grid is perfect for directing the light a little more.

A clamp or mini tripod is recommended. This gives you more options for positioning the RM 40C. However, I have not yet found a mini tripod that works well for this. It should not be too large, but not too small either.

Conclusion

The SmallRig RM 40C is a useful tool for adding background light to video. I have already made grateful use of it when recording video for Photofacts Academy. Using the RGB colours adds a lot.

Screenshot from the Nikon Z video course on Photofacts Academy. The colour effect of changing colours was used with two RM 40C units.
As a main light, 40 watts is not enough. You could use it as a fill light, possibly when filming with a smartphone. The RM 40C is small enough to carry around easily. Do bear the noise in mind.

The distribution of the RGB LEDs.
As a light source for photography, it is perfect for macro. The light surface is large enough to produce reasonably 'soft' light. If you move beyond macro and choose to light larger subjects, the light quickly becomes 'harder.'

A grid and diffuser, and the magnets that keep everything in place. It works well and everything stays perfectly in place.
The magnet on the RM 40C has limited usefulness. It is only strong enough for flat metal surfaces. Even then, you need to be careful that the unit does not slide down. The magnet is on one side, so the weight is not distributed optimally.

The magnet on the back is not strong enough to hold the 302 grams securely on vertical surfaces.
The SmallRig RM 40C is a useful addition for photographers who need some extra light, such as for macro photography. The light output is more than sufficient for this type of photography. It can also work perfectly as an extra accent light in a flash lighting setup.

That small touch of accent light can make a big difference. The RM 40C is perfect for this.
For anyone recording video, it is also useful as an extra accent light. As a key light, it is still not sufficient in many cases, unless you can place the RM 40C very close. Of course, you can also keep the panel itself in the frame.

Pros

• Good and compact design
  
• Many adjustment options and effects
  
• Simple and intuitive operation
  
• Very wide colour temperature range
  
• Unit can be used while charging
  
• Magnetically attachable grid and diffuser
  
• Magnet for positioning on metal surfaces
  
• Fan provides sufficient cooling and works automatically
  
• Clear display for settings
  
• Good price
  

Points for improvement

• Ability to link multiple units
  
• Magnet on the back is not strong enough
  
• Control dial is pressed too easily
  
• Side button and switch could have a little more profile
  
• An additional 1/4"-20 connection on the side would be useful
  
• Make the fan speed adjustable as well as automatic
  
• Fan is not silent
  

Thanks to SmallRig for providing the RM 40C for this review.

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