u/autruchedor

Hi!
I just bought a set of infrared filters (Neewer 4-piece infrared filter set: 720, 760, 850, 950nm) and I wanted to try to do a trichrome image, but only in the infrared spectrum. By subtracting exposures, it looked like it could be achieved.

I used Blender to subtract and combine the exposures, but the result is quite disappointing. There is no real color (other than movement artifacts and, I think, the fact that I didn't hold the filters perfectly straight in front of the camera).

All 4 exposures look very similar. I wonder if the filters are the issue (I couldn't find any spectral curves or datasheets for these filters) or if it's just not a practical idea. See the last 4 images, in order: 720, 760, 850, and 950nm.

Camera I use: Full-spectrum Leica C-Lux 3 (aka Lumix DMC-FX37).

Hey everyone, The Reveni Labs Spotmeter Mk2 is a very handy piece of tech, but it has a couple of quirks: the infrared sensitivity (which I posted about fixing recently) and parallax errors when metering subjects at a close distance. To solve both, I made a 3d printable mod. The new adapter still holds the same 10mm (0.55mm thick, 650nm) IR-cut glass filter to fix the foliage underexposure, but it now also features a custom mount for a small laser diode.

I used a 5mW, 3V laser diode (6mm diameter, 10.5mm long). The laser is powered directly by the spotmeter's two internal AAA batteries. You simply jam the stripped cables between the batteries and the connectors, so there is no internal soldering required. The laser is then easily activated by a small button on top of the mod.

The only non-reversible change you have to make to the meter is carving a tiny notch into the battery compartment door to let the cables pass through. The main 3D-printed adapter is held in place with a drop of flexible glue (like T-7000), which keeps it secure but remains easy to remove later if you ever need to.

When you first install the mod, the laser won't be perfectly aligned. You just need to aim the meter at a distant target and manually nudge the mod until the laser lines up perfectly with the internal reticle. Because the laser is mounted about 1 cm below the sensor, the laser spot will hit about 1 cm below your metered target. But you can easily 'triangulate' your target by comparing the laser spot with the meter's reticle (check out the 3rd image for a simulation of what you actually see).

The best part is that even with this entire mod attached, the meter still fits perfectly inside its original little cloth pouch!

I’ve uploaded the updated STL files over on Printables. https://www.printables.com/model/1729948-reveny-spotmeter-mk2-laser-and-ir-cut-mod

(I printed it in resine but it should work fine in filament) (And I will try to reprint it with custom supports for a cleaner result) By the way, I still have 4 extra diodes and filters left over if anyone is interested!

Let me know what you think!

Hello everyone, I've been using a second-hand K40 laser cutter for a few weeks now (it still has the stock M2 Nano board and I'm using K40 Whisperer).

I was rastering some images at 500mm/s and 15mA, and it was working perfectly fine. The job took about 30 minutes (see 3rd photo). Right after that, I wanted to run a calibration test card featuring a solid square and a gradient (2nd photo). I started the first one at 15mA and 500mm/s, but mid-rastering, the laser beam just shut off. (For context, the water cooling was at a stable 20°C). Now, I can no longer fire the laser at all. There is absolutely no movement on the analog mA dial, though the control system and gantry still move perfectly fine when I run a file. I safely disconnected the power supply (making sure to discharge the red high-voltage cable to ground first) and started poking around the PSU board with my multimeter. It looks like one of the transistors is dead (I tested it in diode mode, see 1st picture). My questions are: Is 500mm/s at 15mA a bad/stressful parameter for this machine? Did the duration of the previous job combined with the dithering/gradient cause it to fry? Or is this just bad luck with cheap stock components?

Thanks for your help!

Hey everyone,

I recently noticed my Reveni Labs Spotmeter Mk2 was giving me some wildly inaccurate readings on IR-reflecting subjects, especially vegetation. I did some side-by-side testing with my digital camera and a Pentax Spotmeter V, and on grass/foliage, the Reveni was reading way too much light which would result in a 1 to 1.5 stop underexposure on film. It turns out the sensor is sensitive to infrared light.

To fix this, I designed a 3D-printable adapter that holds a 10mm IR-Cut glass filter (650nm, approx. 0.55mm thick).

The design features a built-in lens hood to prevent sun flares from hitting the new glass filter and messing with the readings. It mounts to the spotmeter via a simple press fit, though I personally added a tiny drop of flexible T-7000 glue to keep it perfectly secure without making it permanent. I also included a small notch at the bottom to indicate the orientation, making it easy to know which way is up when installing the adapter.

Because the filter glass slightly reduces overall light transmission, you'll need to tweak the calibration offset in the spotmeter's settings. For reference, my factory calibration was set to +0.1 EV, and I bumped it to +0.4 EV to compensate for the filter. Now it matches my other trusted meters perfectly!

I’ve uploaded the STL files over on Printables if anyone else wants to fix their meter. Let me know what you think!

https://www.printables.com/model/1713924-reveni-spotmeter-mk2-ir-cut-filter-adapter-lens-ho