alt Hacker NewsA problem for multispectral imagery (even within visible rgb), is that the wavelengths of light are different so the lens cannot be in focus for all spectrum at once. I have tested this out with a few of my slr lenses. If you have blue channel perfectly in focus, red isn't just a little out of focus, it is actually noticeably way out.
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there are lenses out there designed for apochromatic performance across the UV-Vis-IR band, but they tend to be really pricey.
The Coastal Optical 60mm is a frequently cited one. UV in particular is challenging, because glass that works well in the visible light range can be quite poorly translucent in UV. Quartz is better, but drives up the cost a lot, and comes with other tradeoffs.
I've had this problem as well, but it's just due to optical properties of the lens and extremely consistent from image to image, so you can calibrate and correct for it as long as you focus each wavelength and collect data separately.
This is called chromatic aberration, for those who are intrigued.
Given that regular phone cameras have sensors that detect RGB, I wonder if one could notice improved image sharpness if one had three camera lenses (and used single-color sensors) next to one another laterally, with a color filter for R, G and B for each one respectively. So that the camera could focus perfectly for each wavelength.