No head, no glass 4700 lux / 850 lumens
With the head and no glass 3750 lux / 673 lumens
With the head and cleaned original glass 3380 lux / 606 lumens
With the head and coated glass 3890 lux / 698 lumens
I find it extremely hard to believe that the coated glass transmits more light than no glass at all.
It's also rather startling how much light the head is eating. I'm surprised it is that much.
Well, it's a 3.7% difference between coated and no lens which has to be within the error of the light meter, box, battery, etc. And from what I've read, coated glass passes 99% of light so that 1% wouldn't be easy to detect anyway. Coated glass is still 15% better than plain glass (clean glass 10% better than dirty glass). For the price, Solarforce should really be supplying coated glass, at least with the L2P and higher. It's a pretty inexpensive upgrade. I'm sure people have swapped out LED's just to go from Q5 to R2, so this will get you at least that much more light for $3 (and no soldering!).
I ordered my lenses from KD about the same time you did, so hopefully mine will be here soon (next week, I'm thinking; yours showed up fast). Thanks for running the tests; those are amazing numbers.
KD HD lenses: Violating the laws of thermodynamics, one at a time!
Could be some other variable influencing the reading, try putting them in the beam of a fixed light source and see how much of the light they remove.
Might as well be true. Aspherics used to concentrate the beam usually up the lux readings at relative distance. This lens and coating might do the same but on much lower scale and above that probably just by "manufacturing error" not specifically designed to do so.
Some more testing would be nice. I have 3 lenses from KD and a light meter on the way which will arrive soon. I'll do the homework as strictly as possible trying to eliminate as much variables as possible (same host, same cell voltage, same distance and focus to lux meter, ambient and dropin temp... ). Will do 10 readings in each setup and average them to further minimize the margin of error. Will use a single mode r5 dropin i have which is well regulated for the assessment. The XM-L would not be best for job i believe.
Thank you Don for confirming my findings from the earlier posting, I doubted my own numbers but how many camera lenses and binoculars are not coated.
I don't have to feel to guilty for making so many members spend their hard earned cash.
Finally got my 3 $2.99 lenses from KD. You can't really tell they have coating on them, but they do seem less reflective than regular lenses. I took the lens out of my Solarforce L2i and replaced it with one of the coated lenses, then took some backyard photos, swapping out the head of my Solarforce L2 with the original lens in it. I tried four different drop-ins, but I'm only showing 3 because the camera, stand, or light shifted from one picture to the other.
Here is my KD XM-L drop-in with the AR coated lens on the left and the original lens on the right. I did clean the old lens first to make it fair. I don't see much of a difference, but I would give the edge to the AR lens:
Now a cool white XP-G R5:
Last is a neutral white XP-G R4, but white balancing makes all of these tints look about the same:
I want to push this thread a bit.. I got a coated lens from KD last weekend... I changed it with the stock lens on a Solarforce L2T and did some measurements.. Im very excited, its a increase of about ~8% to the stock lens. I cleaned the stock lens before with alcohol. Will order a package more for my P60 hosts :)
Easy and cheap way to pull out some more lumens of your p60 hosts
The difference between using an AR coated lens vs uncoated is basically the same as the difference between R4 and R5 bins. It isn't a huge difference and it is quite hard to spot it by eye, but it is there and using cheap AR coated KD lenses is definitely worth it.
Once you have a great emitter and a great driver it makes sense to have the decent lens added. Ultimate budget light.
I appreciate the thread bump.
After going through the motions with purchasing a couple of UCL lens for my Solarforce lights and DRY, I instead went ahead and bought KD's $2.29 28mm*2mm lens instead of their more expensive $2.99 version. I went the budget route with the 54mm*2mm as well and bought the cheaper $2.90 instead of $5.26 version.
It'll be interesting to see if it improves light output from my Linger Special and Kerberos drop-ins, and possibly eek out a couple more lumens out of the DRY after I also did a quick tail-cap resistance mod to it!
Installed it on the quad, Linger and DRY and found a 3.88%, 3.19% and 3.57% (respectively) improvement in ceiling bounce lux measurements on high, compared to the stock lens. However, I could not visually tell the difference between stock and KD lens.