# Exposure and light

**URL:** <https://forums.kinograph.cc/t/exposure-and-light/2470>\
**Category:** Machine Design\
**Created:** [February 1, 2023, 6:39pm UTC](https://forums.kinograph.cc/t/exposure-and-light/2470 "2023-02-01T18:39:43Z")\
**Posts on this page:** 1\
**Showing post:** 10

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**Author:** ![PM490](https://forums.kinograph.cc/user_avatar/forums.kinograph.cc/pm490/32/3176_2.png) [@PM490](https://forums.kinograph.cc/u/PM490)\
**Post date:** [March 13, 2023, 2:27pm UTC](https://forums.kinograph.cc/t/exposure-and-light/2470/10 "2023-03-13T14:27:55Z")

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@agus35monk I am using 55mm ping pong (oversized) ball, which is decent for an 8mm target. No coating was used, I did select that the visible portion does not have the hemisphere seam or the injection mark.

@justin thank you for sharing these references. The last reference uses this interesting [aluminum cake molds](https://www.amazon.com/gp/product/B09S24J4Y3/ref=ewc_pr_img_1?smid=AVQZ6Z4LCAKI5&th=1), which are available in various sizes. The part looks like a promising half sphere, perfect for light sanding and coating. As mentioned by @cpixip, the relation between the diameter and the port size, and the reflecting surface are critical.

> [@Alpha-Release of new picamera-lib: "picamera2" ... - and beyond](https://forums.kinograph.cc/t/alpha-release-of-new-picamera-lib-picamera2-and-beyond/2356/5):
>
> In this [article about the Universidad de la República](https://agu.udelar.edu.uy/laboratorio-de-preservacion-audiovisual-lapa/dominio-tecnico/actualizacion-de-la-plataforma-de-digitalizacion-de-filmes/) updates of their scanner, they listed an interesting plug-in for [creating surface plots from an image for 3D visualization](https://imagej.nih.gov/ij/plugins/surface-plot-3d.html). I have not used any of it, but a similar graphical representation would be a great way to illustrate the alsc issue.

As mentioned prior, imageJ is a great tool to measure the resulting flatness of the illuminant+reflector+lens+sensor+library and provides a great visual representation to confirm the system is flat.

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