Yeah, what Barkuti said. If knowingly new AR coating will eliminate Duv raise then it’s ok to change process, otherwise plain and simple uncoated lenses are just perfect.
If Simon wants to endorse some new product, I can understand. But from the perspective of a buyer, a new product must provide a useful, advantageous reason to be.
I could for example say that, if aiming for lenses with a double coating, one could be set at 475nm (at the cyan dip the usual blue pumped white leds have), and the other could be centered at 650nm (to boost reds). I've checked a few led spectograms around here to conclude this (1, 2, 3 and 4). This would cover the visible spectrum a lot better, while a double coating may still be affordable.
Still, plain or uncoated lenses are a sure win. They're also the cheapest ones so, how about some uncoated lenses? ;-)
Yes, I’m sure. The advantage would be higher transmittance than uncoated glass and improved tint (lower Duv).
I have confirmed myself with my own examples of “green” AR coated glass that it does indeed slightly decrease Duv.
Price shouldn’t really be a concern. Simon’s current AR coated glass for the C8 is $3.94 for a set of two. I’d gladly pay a few extra cents for an improved coating. That said, clear uncoated glass would also be preferable to the currently available AR coated offerings.
Just curious but, what type of anti-reflective coating is that which shows green reflections? Could you elaborate a bit more?
I guess these red/pink/purple reflections you mention are the ones I see in the glass of my S21A, and as far as I know in this regard (not a ;-) lot) these must be a sign of a λ/4 MgF2 coating centered at 550nm.
In the graph you showed from the article you can see that UV-VIS is more effective in the blue and red range compared to green, so the reflections are going to look green, and duv will decrease.
Looking at camera lenses you can see different reflected colors from each lens, orange, cyan, green… etc from different types of coatings, combined it ends up neutral.
In order of preference (in my opinion) :
1) AR with higher red and blue transmission, reflects more green, decrease duv/improve tint, higher overall transmission than plain glass, i.e more efficient.
2) AR with close to neutral transmission, higher transmission than plain glass. (those are probably more expensive)
3) plain glass (of good quality or course, as you mentionned not with iron (green) impurities).
4) currently offered AR lenses : higher green transmission, reflect more blue and red, increase duv/degrade tint. Higher transmission than plain glass.
Thanks. So indeed other types of coatings are being used, which after all means it is inexpensive or affordable to get a hold on them.
Useful information, thanks.
From the previously posted graph, I think VIS 0° is top choice, with comparatively better transmittance of red frequencies, excellent balance and should also lower Duv a tiny bit.
Still, can't help saying that uncoated lenses are perfectly balanced and cheap.
I have done a quick search about transparent anti-reflective film and found certain information, although I'm not going to go on with it now because at this moment we certainly don't know what type of technology are you speaking about or can get a hold of.
However what I can certainly say is that if you can get some example lenses, from what I can see here in post #5463 it is clear that you can certainly test them to know if they will be liked. The goal is:
Lenses or lens coating must not raise Duv; if they lower Duv a tiny bit it can be nice.
Beam CRI or CRI with the lens on must be as good as it is without lens (R9 should not go down, and etc.).
Just in case, without any sort of testing it can be clearly understood that uncoated quality lenses meet both conditions. O:)
I have a question, which is a sincere question. What is the purpose of anti-reflective coating on our flashlight lenses? Is there some kind of glare that it eliminates ? If so is it glare on what we are lighting up or from the lens itself?
To my knowledge, it is used in order to get more light through the lens. Otherwise, some of the light would reflect back into the flashlight itself instead of going out the front. A lot of AR lenses are claimed to have ~99% transmittance. Uncoated glass is less. How much less, I’m not sure (maybe 5% less?).
The point is the driver board, which is not a FET, but a constant current. As long as the driver board is completed, the rest of the work will be done quickly.
The manufacturer has done samples three times, but each time the samples are done, it turns out that it is very difficult to purchase chips. The supply of chips is extremely unstable this year.
I want to temporarily remove the reverse charging function.