I am looking through the images a bit now, I’m not really sure what to make of the far red one
It looks so different from the others, I assume part of it is because it’s getting further from the “absorption peaks”? I wonder what more NIR would look like
I wonder if maybe going further out almost looks kind of like a “gamma adjustment”, like if ratios between the colors kind of get smooshed together. One thing that picture kind of made more apparent to me is that the highlights and shadows in the other ones are pretty “unnatural looking” as they are
The violet seems very similar to the royal blue to me, but it’s also notably more out of focus than the other pictures and there seems to be some light leaking on the right hand side
I’d be interested to see if you have a sample with some different colors in it, like yellow, and also what they look like with a color camera and white light
Did you adjust the focus between the photos? For example, the text on the very first sign seems most “defined” in the royal blue photo
It looks like the focal plane was held constant. It’s actually the len’s “fault” that some of those are out of focus. At this scale it’s relatively easy to see the dependence on wavelength that causes axial/longitudinal chromatic aberration.
The Componon-S 50mm is only achromat corrected, so if you get your red or violet channel focused perfectly, green will be noticeably blurry if you don’t move the lens.
I measured this a couple years ago vs. the APO-Componon 45mm. Check out the green line in the graph about halfway through this post. The APO version of the lens essentially solves the problem… but at roughly 8x the price of the achromat.
You can try to mitigate the problem a little by stopping down the aperture, but both of those lenses have a sweet spot and are sharpest at a particular F-stop, so it’s not a perfect solution.
I can confirm that focus was not adjusted between pictures. I only changed the led behind the frame.
There was some frame movement noted in the second set captured, most likely from my fumbling around in a dark room and bumping the holder, but I don’t think that should have changed any focus related distances.
I also ended up using these LEDs, I originally wanted to use osram ones but the line I wanted didn’t have a photo red. I am very slow but I should have all my stuff done in probably 1 or 2 months. I have royal blue, blue, cyan, green, amber, red, photo red, and white for my boards.
