X rite colorchecker passport magenta tint

Started 4 months ago | Discussions thread
Iliah Borg Forum Pro • Posts: 28,803
Re: X rite colorchecker passport magenta tint

ggbutcher wrote:

Iliah Borg wrote:

ggbutcher wrote:

The guy at MaxMax just piped the monochromator output into a fiber optic cable and pointed it directly at the sensor on the lens-less camera... ??

Not exactly 'just'. Dan wrote: "We split the monochomatic light output between two fiber optics cables. One was routed to our spectrometer and the other was routed to the camera."

Fair 'nuf. But, the salient point is, didn't use an integrating sphere.

In my early experiments I bounced the monochromator beam off a gray card, or used a diffuser. Later I bought an integrating sphere for $129 (ebay). Next, I found out a sphere is easy DIY.

One of the questions here is the uniformity of the sampling area. However, for analyzing converted JPEGs one doesn't need much accuracy.

Yes, was thinking along those lines as I posted the response. Could insert a diffuser and essentially take a picture of the blob, but then there's the diffuser and lens in the path to factor into the measurement. Splaying the light directly on the sensor, with only the fiber to account for, seems to be the least complicated way to accurately present light for measurement.

https://maxmax.com/faq/camera-tech/spectral-response

If I were wanting to go into the business of measuring cameras' spectral response, a monochromator would be my first choice.

Consider OL 490 Agile Light Source.

But I only have three cameras here in my basement, and not much motivation to chase the measurement of many others. For this use case, the homebuilt $130US single-shot spectrometer approach renders data of sufficient quality, within 2 dE (24-patch ColorChecker) of a monochromator-based profile for the same camera.

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