I was curious to get a red P0 drop-in (and that full spectrum pink, but held off so far). I’d heard how “red” far red was but failed to look any further into it. So I got it, thinking it was just the nicer looking red compared to others. When it showed up, the red was really nice but I was quite disappointed with the output. It claims 280 lumens and 1.5A but it looks like just a few lumens and measured around 5 lumens in my Texas Ace lumen tube. Then I read more about it and it’s barely in the visible spectrum. How visible might vary from person to person, and it probably varies from device to device in terms of cameras, lux meters, etc picking it up which is probably why the lumen tube roughly matched what I was seeing.
So I decided to do a comparo with my other red light, a Convoy M21A B35AM 3500K with a red slip-on filter. And I used my phone camera (which, I’ve no idea how sensitive it is to far red, but it roughly matched how things look to my eye) and a device which can see farther into infrared, like 800-900nm. I did not attempt to lock exposure. Both beams are always there so you can see the relative difference. And the IR-capable device can’t be set to a fixed exposure anyway. I cycled through the 5 levels on the Convoy to see how bright they appeared relative to the constant-level far-red drop-in. It was kind of a challenge to hold everything and record, so excuse the somewhat crummy pictures.
Far-red on the left, Convoy on level 1 (0.1%) with red filter on the right:
Far-red on the left, Convoy on level 2 (1%) with red filter on the right:
Far-red on the left, Convoy on level 4 (35%) with red filter on the right. Note the device has a circular view which is why there is heavy vignetting, it’s not the spill of the two lights ending there:
To my naked eye, the far red looks closest to level 2, but really kind of between 1 and 2. Both level 1 and 2 with the red filter fail to register on my lumen tube. Level 3 is ~25 lumens, then ~90 then ~190. To my non-naked eye looking through an infrared capable device the far red looks closest to level 4, which is around 90 lumens. The beam intensity isn’t the same for both though so it’s a bit harder to say. But far red is putting out a lot more energy than it looks like to the naked eye.
It’s neat, but I wouldn’t get it again. It’s using a lot of power to make hardly any visible light. The Convoy on level 4/35% is pushing around 5W, the far red is like 4.5W yet it looks more like the 0.1% Convoy level. I’d probably have gone with photo red if I’d known this at the time. There’s no far-red filter for incan lights that I’m aware of, but I feel like if there were, a real P60 incan and a filter like that would make about the same amount of red light and run for the same amount of time, so this seems like a really inefficient way to make visible red light.
