Perfecting the Olight ArkPro series with high CRI LEDs, optic modification, and custom parts

2 Comments

1. bob_mcbob 7 days ago

   The ArkPro series doesn’t really need an introduction, but it’s a very popular update to the Arkfeld flat lights. I’ve modded several dozen of these since they were released, and I wanted to share some insights and data before the new black ArkPro Ultra drops tonight.

   #Pricing and Availability

   I keep all colours of the ArkPro series in stock to sell modded. Exact pricing varies a little depending on colour and LED options.

   * ArkPro: $115 USD

   * ArkPro Ultra: $135 USD

   With that aside, let’s dig into the details.

   #ArkPro Flood

   When I started modding the standard ArkPro, I immediately noticed that 519A and especially FFL351A/NTG35 produce some ugly beam artifacts in the flood optic. I thought it might be a centering issue, but torturing my 3D printer into making a tiny centering adapter just made the artifacts more consistent. I tried several options to fix this.

   * Frosting the rear of the glass: Impossible because the AR coating is so delicate that it can’t be masked or even cleaned.

   * Diffusion films: Most of these are thick enough to prevent the bezel from fully reseating, and there’s a potential for yellowing over time.

   * Sanding the optic: Works acceptably but produces a very unprofessional finish.

   * Sandblasting the optic: This is what I eventually settled on, but I went through several expensive ultra fine abrasive medias to find one that produced a fine enough finish to not impact light transmission too much (under 15% like d-c fix).

   You can see all of this in one of the gallery collages, including a finished light in the middle. I pretty much exclusively use 519A and FFL351A/NTG35 for the flood.

   * 519A: Gorgeous neutral tint and high CRI. I have a limited supply of the discontinued 4500K to use for this mod.

   * FFL351A/NTG35: Somewhat higher output than 519A, and a tighter beam, a little more similar to the stock flood. Ultra rosy tint available.

   #ArkPro Ultra Flood

   The Ultra uses a 5050 3V LED, which has always been a challenge for high CRI modding. The two most readily available options are 2700K/3000K SFT-40, and 3V 5000K FFL5009R.

   * 2700K/3000K SFT-40: A gorgeous direct replacement for the original. Somewhat lower output due to the low CCT.

   * 5000K FFL5009R: Generally mediocre tint, but can be acceptable with careful and expensive manual selection.

   * Other Chinese LEDs: I also have several LED options similar to FFL5009R in 1800K, 3500K, and 6000K, all extremely high CRI and better tint. The 3500K is unfortunately limited to about a dozen samples since it was a small custom run.

   #Spot/Throw

   My preferred option both lights is FFL351A/NTG35. It’s less throwy than the stock SFT-12, but actually higher output in some cases, and still gives a very clear distinction in beam profile compared to the flood channel. It has the best beam quality and allows a wide range of CCTs. I can also use the new 5700K CRI 90 SFT-25R or the higher CRI 4500-5000K “HT35” LED from Hopthink/Kaidomain. These both maintain the more pencil thrower beam profile, but tend to have highly variable beam quality in the ArkPro reflector, which I’ve noticed with the stock LED as well.

   #UV

   I was a little skeptical about this due to the different Vf, but I’ve successfully swapped white and red LEDs here. With a white LED like FFL351A, the lower level has a slow ~1.2Hz flicker that most seem to find acceptable, but it should be noted. Red LEDs don’t have this issue, but the beam has a ringy profile that I finally decided to bite the bullet and resolve with custom frosted glass to replace the original UV filter (I tried everything else I could think of here, but it’s a much more difficult issue than the ArkPro flood optic).

   #Colour

   There’s not much point in posting measurements. The stock LEDs are mostly very cool white, CRI 70 or lower, and with such variable tint that any one sample is not representative. Most of the spot LEDs are very green except on turbo, and the flood LEDs run the whole range of tint.

   The replacement LEDs I use all have superb tint and colour rendering.

   #Output

   Here are a few example lights. Note that the standard ArkPro has higher output with FFL351A/NTG35 in the flood channel, especially with higher CCTs.

   Level | ArkPro (spec/measured) | ArkPro 3500K 519A/3700K FFL351A | ArkPro 4000K 519A/5000K NTG35
   —|:—|:—|:—
   Flood Turbo | 1500/**1405** | 774 | 829
   Flood High | 520/**451** | 268 | 303
   Flood Med | 100/**93** | 58 | 64
   Spot Turbo | 800/**785** | 759 | 891
   Spot High | 400/**370** | 291 | 329
   Spot Med | 100/**96** | 68 | 78

   Level | ArkPro Ultra (spec/measured) | 5000K FFL5009R/5000K FFL351A | 3500K dedome/3700K FFL351A
   —|:—|:—|:—
   Flood Turbo | 1700/**1438** | 1139 | 891
   Flood High | 520/**416** | 314 | 244
   Flood Med | 100/**82** | 61 | 48
   Spot Turbo | 800/**739** | 832 | 756
   Spot High | 400/**373** | 319 | 296
   Spot Med | 100/**92** | 71 | 69

2. Pandaepidemic 7 days ago

   Are you a wizard?