07:23 | se6astian | polyrhythm: we decided to not take any venture capital so VC means video call or video conference :)
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07:24 | polyrhythm | yeah, that's what I thought!
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07:24 | polyrhythm | i've worked in california for too long obviously
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07:25 | se6astian | digitalbolex, great, I also have access to some academic equipment, though probably most of it not useful, I spectrally measured our UV/IR cut off filters
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07:26 | se6astian | https://www.apertus.org/axiom-team-talk-15-4-optical-filters-firmware-2-article-june-2020
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07:26 | se6astian | I am not sure though this particular device can measure non transparent objects though
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07:27 | se6astian | as its a separate emitter and measurement unit with a small gap in between
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07:27 | se6astian | Max does not have any high CRI led lights currently and would start with tungsten lights
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07:28 | se6astian | would that be a good first step or will the measurements only make sense when we also have a daylight set?
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07:28 | se6astian | for which I would need to organise the daylight leds for a day or so, but I cant hand them over to max as they are used in projects every now and then
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07:45 | polyrhythm | I think we can start with tungsten lights...
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07:45 | polyrhythm | at the end of the day we want two different matrices, one under tungsten and one under daylight, but one is better than none
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07:45 | se6astian | LEDs would be aputure LS 300X with CRI ≥ 96
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07:45 | se6astian | great!
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07:47 | polyrhythm | Aputure LS 300X seems a-okay :)
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07:55 | polyrhythm | regarding spectral profiling of a sensor, it does not look cheap...haha.
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07:55 | polyrhythm | https://www.image-engineering.de/products/technology/spectral-sensitivity
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07:55 | polyrhythm | this company seems to specialize in it.
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07:55 | polyrhythm | https://www.image-engineering.de/products/equipment/measurement-devices/588-camspecs-express
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07:55 | polyrhythm | 16,500 euros!
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07:55 | polyrhythm | Weta Digital built their own spectral measurement device dubbed "Lightsaber" which always profiles sensors.
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07:55 | polyrhythm | basically you point a light of a known wavelength at the sensor and record the output
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07:56 | polyrhythm | I don't think the thing you used will work in this case, but if you have access to anything remotely like what I linked to above (or anything with a name like "monochrometer") let me know
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07:57 | polyrhythm | the problem this solves is essentially figuring out, in a very accurate way, the absolute limits of what the sensor can read.
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07:57 | polyrhythm | test charts can get us a decent sample set for typical images but not really the edge cases unless we start devising a ton of clevery-designed setups like certain hues of neon lights and so forth
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07:58 | polyrhythm | in reality it's not necessary to go this far for a cinema camera. weta's use case is that they try to recreate the camera in CG so they need to go this distance to get the result they need
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08:00 | polyrhythm | i'm sure Arri, etc., do this kind of thing for their color science though as well
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08:00 | vup | I mean building something like a monochrometer doesn't seem too hard, right? Using a prism with a "white" light and blocking most of the output (and maybe calibrating with a spectrometer or two different color lasers) doesn't seem too hard
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08:01 | vup | the main problem is producing the same intensity for every wavelength I guess
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08:03 | se6astian | I keep grazing ebay for an old spectrometer or sekonic color temperature measurement device...
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08:04 | se6astian | vup, I think we have different definitions of "too hard" :)
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08:14 | polyrhythm | yeah I think it's one of those things where the devil is in the details. I think you could probably cobble something together but when accuracy is the name of the game, that's when it gets difficult
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08:15 | polyrhythm | and that's why I spend $200 for a flimsy piece of paper with dumb little color patches on it. because a manufacturer is assuring me I can trust it, versus just printing one out
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09:04 | vup | maybe there are a lot of details, but I think you can get something reasonable with not too much pain
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09:04 | vup | accuracy is pretty relative, I don't think we need a lot more than 8 to 12 bit, right?
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