This thread is to collect measurements on the various AR lenses available in the market. I will periodically update this OP as measurements are submitted. If you have a thread on a lens you measured, please provide a link and I will include here.
CNQ Glass vs Various Stock Glass (42mm, 55mm, & 58mm) (Sep Thread Post 43) - Average 8% increase over stock glass lenses
Stating percentage increase over stock isn’t the best way to evaluate a lens. A better way is to measure how efficient a lens is. Please see my testing on various lenses (as well as some other things) for Solarforce hosts here.
But if everyone uses stock glass as a base, then what’s so bad about measuring the percentage increase when switched to other lenses?
The efficiency is not as important as the transmittance relative to stock glass because the stock glass is the base line, nobody uses lights without lenses, so it’s not that important to measure it without the lens.
When I modify a light I want to know if I made an improvement or not. It’s also nice if I can answer that question with a minimum amount of time, effort and equipment. Given those parameters, is measuring efficiency a better way to do this than measuring the percentage of change, and if so, why?
Stating percentage increase over stock isn’t the best way to evaluate a lens. A better way is to measure how efficient a lens is. Please see my testing on various lenses (as well as some other things) for Solarforce hosts here.
That looks like some fine testing you did there. I only scanned it and will try to read and understand it when I'm not so tired. The only thing that stood out was that I couldn't really tell what specific products you tested. I will consider your advice and improve this thread if I can think of a way to do it.
I will admit that my tests were sloppy and not ideal. My intention is only to provide a reference to any measurements made by anyone regardless of their approach. Hopefully, there will be enough cases to enable members to make more informed choices. I purchased over 20 lenses from CNG. I will be measuring and documenting each one as I install them. I will document the specific light and lens replaced. I will most likely continue to use the same approach because it is easy and fast. I just have too many other things going on in life to do any more than that.
Its all about consistency. If you take a look at the test results in the thread I linked earlier you will notice that I tested the stock Solarforce glass lens twice. First it was tested as-is from the factory/Solarforce and then a second time after being cleaned. The difference between the two was around 2.23%. Its not a huge percentage but nonetheless there is a difference. Suppose two people are using two different L2’s with stock lenses. Person A has a stock lens that is dirty and Person B has a stock lens that is clean. Both lights lenses are then upgraded to the same AR lens. Person A and B both report back the difference in light output relative to the stock lens they were using. Assuming they both have the same exact test setup/proceduce (yea right… just a hypothetical example) to measure light output they will both have different numbers. See the problem?
Depending on how you look at it the stock lens can and cannot be considered a baseline. Sure it is a baseline if you want to use it as a comparison point against a different lens (faulty comparison as shown in the example above). But it is also not considered a baseline when you look at the output as a whole system. What I mean by system is emitter~~reflector~~>lens-> OTF. The lens is a variable when it comes to the entire system. Variables can lead to differences in data. If you know how much that variable will affect your results (in this case lens efficiency) then you will have results that are predictable.
I know the above explanation is a bit long and winded but I want to be as thorough and clear as possible. When it comes to testing I always like to keep the Scientific Method in mind.
I definately recommend a cup of coffee and a clear state of mind when reading it. The testing shows how reflectors, lenses, and bezels affect light output for the Solarforce L2 series.
Its wonderful that you have taken the initiative to create a thread to gather info of various AR lenses. Assuming enough information from forum members is contributed it can save quite a good amount of time when searching.
I understand your reasoning behind this, but seriously who doesn’t clean the lens before testing?
Aside from that though, you are completely right and measuring efficiency of the lens does have merit.
I don’t have 100% confidence in my lumen calculations which is why I measure it at a % difference relative to each other.
I am okay with the improvements of the lens it’s not scientific but its practically because we get a clue how much improvement we can get in real application…
Yeah, a 5 to 8% improvement improvement in output is hard to detect with our adjustable eyes. I think you need to be in a situation where that extra 5% makes a different. Like trying to see something at the far end of the beam pattern.
I have noticed a smoother beam profile in some of my lights. It is cool to sometimes think you don't have a lens and have to check to make sure.
The testing shows how reflectors, lenses, and bezels affect light output for the Solarforce L2 series.