Boaz has DC-Fix for sale as well:

http://budgetlightforum.com/node/42208

This stuff is fantastic. I’ve used it on a lot of lights, and it turns the ugliest beam into a work of art.

Just bought 2 meters roll

Thanks maukka for doing the testing for us. Now, could someone make those before and after CRI test charts into a mouse-over so that the miniscule differences can be seen quickly?

Thanks for testing, Maukka.
Only 5 – 10% loss in output is better than i thought it would be.

A test with everything you could possibly want to know about using dc-fix on your flashlight
Great test!

Thanks for taking the time to do this. It’s good to have this sort of information documented.

Long term, it might be nice to have this kind of information indexed somewhere for easier access than sorting through forum threads.

Also, has anyone ever done a controlled comparison of DC-Fix vs. a matte finish tape like Scotch “Magic?” I’m curious if the DC-Fix diffuses a different amount, is more durable, sticks better, etc.

What is 803?
Also, measurements don’t look like 5-10%

Agro wrote:

What is 803?

For heat concerns, Lee makes a Zircon line that is heat resistant:
http://www.leefilters.com/lighting/zircon.html#zircon-minus-green
The 802 Zircon Minus Green reduces lumens by 25%, that would be closest to the 1/2 minus Green, that reduces by 28%

the following percent numbers are the amount of light transmitted, so 71.5% transmission means 28.5% lumen reduction..

Lee 248 Half minus green: 71.5%
Zircon 802: 75%

Zircon 803: 79.9%
Lee 249 -Quarter minus green : 81.5%

Zircon 804: 83.6%

Zircon 805: 86.6%
Lee 279 -Eighth minus green : 87.2%

Discussed here
http://budgetlightforum.com/comment/1117960#comment-1117960

Examples of with and without Lee
http://budgetlightforum.com/comment/1234356#comment-1234356

Thanks for the explanation.

So, output is cut ~10% but intensity is cut ~30%.

So, a floody light will lose less intensity than a thrower? Is it a logarithmic effect?

I haven’t done the math or the measurements so this is just a guess, but it might just be a function of lens size. Bigger lens = more diffusion film = more diffusion.

ToyKeeper wrote:

I haven’t done the math or the measurements so this is just a guess, but it might just be a function of lens size. Bigger lens = more diffusion film = more diffusion.

Okay, here’s a thought. It would be nice if someone would test this hypothesis. Compare a small, but throwy light (such as Convoy C8), to a larger, floodier light (such as BLF Q8), both with diffusion film. I’d love to see measured results.

ToyKeeper wrote:

Bigger lens = more diffusion film = more diffusion.

DavidEF wrote:

Okay, here’s a thought. It would be nice if someone would test this hypothesis. Compare a small, but throwy light (such as Convoy C8), to a larger, floodier light (such as BLF Q8), both with diffusion film. I’d love to see measured results.

https://m.youtube.com/watch?v=mi3hLBouZeY

maukka wrote:

Just an educated guess. If you already have a somewhat diffused light (eg small heavy OP reflector or frosted optics), naturally adding more diffusion doesn’t have the same impact as diffusing a very narrow beam (large SMO reflector).

That’s probably a better guess than mine.

For example, put DC-Fix on a mule. It has virtually no effect. Then put it on a thrower, and it has a much bigger effect. The more collimated the beam, the more it can be messed up by diffusion film. But making a mess out of something which is already a mess… isn’t very noticeable.

With measurements of a bunch of lights, it would be possible to generate a curve and figure out the math. But for now, I really don’t know. The effect is probably something like sqrt(candelas) or sqrt(cd/lm). Except, instead of a square root, it’s probably a different power. Like math.pow(cd, 0.95) or math.pow(cd/lm, 0.75) both get fairly close to the numbers in the OP.

This looks like a good answer:
https://physics.stackexchange.com/questions/102193/relationship-between-...

Agro wrote:

This looks like a good answer:
https://physics.stackexchange.com/questions/102193/relationship-between-...

DavidEF wrote:

Okay, here’s a thought. It would be nice if someone would test this hypothesis. Compare a small, but throwy light (such as Convoy C8), to a larger, floodier light (such as BLF Q8), both with diffusion film. I’d love to see measured results.

I also would like to see the numbers for throwers and flooders but, as ToyKeeper said, the visual effect on a flooder is negligible.

Diffusers are very nice but the drop in throw has 2 effects. First you want to increase output to increase throw again. It’s totally subjective but it’s what you want to do, so one should have more lumens available… Maybe one can get used to it after a few minutes but I didn’t try it.

Second, lots of flood are inconvenient to illuminate farther away so I don’t keep it permanently on the flashlight. I carry several pieces for different flashlights in the wallet; sticking the right one on the flashlight takes less than 1 minute. Removal is also easy and it doesn’t leave dirt on the glass. Dc-fix can be reapplied several times. I glue them back in the plastic cover that comes with it in the wallet to not lose the adhesive.

received fast, ordered from : https://www.ebay.co.uk/itm/d-c-fix-Klebefolie-Selbstklebefolie-M%C3%B6be...

I wonder what’s the light loss with (multilayer) AR coated lens.
Such lens has refractive index of the material next to DC-FIX close to that of air. That would probably negatively impact efficiency…..

I noticed that such diffusor foils/lenses make the outer rim of the spill brighter than the inner parts of the spill. I find this a little bit distracting. The loss in throw is also quite noticeable.

Yeah, PFlexPro lens would be a good choice for quite a few lights. But it’s available in just a couple of sizes….