Review on GVM 50RS RGB Video Light Kit: Full Color Output, CRI97+, APP Control, Studio-quality Lighting for Photography, YouTube, Interviews & Portraits - Includes Carry Case and Barn-Door by David Bott

I bought the GVM 50RS as an inexpensive RGB light. RGB lighting is just beginning to appear on the indie film scene and this was one of the most affordable lights out there. Robust construction, mostly made of aluminium. It uses passive cooling so the fan doesn't make any noise. The yoke is adjustable in different positions. It comes with barn doors. The diffusion plastic sliding in front of the panel does a good job at the expense of stopping or something. I'm not going to use a secondary diffusion that's in the front as it seems to take a lot of time to set up and tear down. If I need extra diffusion I can add about 216 bulbs to the gullwing doors. As I already have good two tone bulbs I probably won't be using the 50RS as a tungsten/daylight source for key or fill lighting. I'll most likely use it to add color to a background or to change the ambient lighting in a small room for a certain mood (horror or mystery). What disappointed me the most was the battery life combined with different colors. In my tests, I used the two largest NP-F batteries, the NPF-970. I was able to power the light from 3 hours 12 minutes (for Red) to about 8 minutes (for Blue) with these two batteries. This seemed a bit strange so I switched to AC and measured how many watts each of the 6 primary colors on the color wheel was using. I also metered exposure by noting the aperture needed for my camera (Sony A7s2 with Rokinon 50mm Cinema DS lens) to see an average gray card at 50 IRE. The light was set to 100% brightness and 100% saturation for all colors. Here are my results: Red - 0° - 21.5W - T1.4 Yellow - 60° - 41.0W - T3.2 Green - 120° - 22.0W - T2.5 Blue - 180° - 42 .0W - T3.6 Blue - 240° - 22.5W - T2.2 Magenta - 300° - 41.5W - T2.7 Magenta consume almost twice as much energy. Perhaps the light combines R, G, and B to create other colors. I was really looking forward to a light that I could take with me in the field without AC power. As I am primarily interested in the RGB capability of this light it may not suit my needs. Looking at the T-Stop column gives a bit of wiggle room, as yellow, cyan, and magenta all increase exposure. So maybe I can run those colors at 50% or 75% and get the battery life I need. Further testing may be required. The biggest plus of this light is that you get reliable, powerful light at a great price. My suggestion for version 2 of this flashlight would be to use a V-mount battery plate on the back so a decent sized battery can provide the power needed for those secondary colors. Users who only have NPF batteries can easily get an NPF 2 to 1 to V mount adapter for around $20.