Diffusion Techniques Testing - Various Methods

Hmm . . . sounds like I need to test another method :) .

-Garry

Ceiling bounce tests are known to favor throwy lights over floody lights, even when they put out the same amount of lumens. It’s a poor substitute for an integrating sphere.

Using a light box, I tested DC-Fix before/after on the exact same light (for a few lights) and got a loss of anywhere from 2% to 7. Usually about 2 to 5, unless I get the film dirty while cutting or applying it. A loss of 26 is almost certainly a measurement error, not an actual loss of that much light.

As for throw, it definitely kills the lux… but that’s kind of the point. I usually see the lux drop to about a third of its original value.

Thanks for chiming in ToyKeeper; thought you'd be a good one to speak out on it.

-Garry

I’d found the post by Selfbuilt on CPF, his test showed 3.2% loss with DC Fix Sand.

I saw Stripes (not the movie), I’m curious to try it either on its own or combined w/ Sand to
see what it does.

http://www.berlinwallpaper.com/dcfix/images/stripes.jpg

Is there a DC Fix that has ribs rather than random?

Ha… answer my own question:

I thought it was about 3% loss.

Interesting. I wonder if anyone has already tried it. Let us know how it does when/if you get it.

-Garry

NightSpy, are you thinking straight ribs (DC Fix Stripes) or some other pattern?

To me, it looks like DC Fix is the clear winner.

I don’t know… I give the DC-Fix and the diffusion lens similar ratings depending on what you are after.
For tail lights, definitely DC-Fix (or aspheric or modified aspheric), for distance and close-up, the diffusion lens is a serious contender.

[quote=siata94]
I’d found the post by Selfbuilt on CPF, his test showed 3.2% loss with DC Fix Sand. I saw Stripes (not the movie), I’m curious to try it either on its own or combined w/ Sand to see what it does. http://www.berlinwallpaper.com/dcfix/images/stripes.jpg
[/quote
]

Lighten up Francis !!!

[quote=Boaz]

This?

-Garry

My favorite diffuser is a frosted lens. Not spray-on frosting, but a genuinely frosted piece of glass like what the Zebralight ‘F’ models use. It provides a basically flawless beam. DC-Fix, OTOH, has lots of little artifacts in the beam. It’s not very noticeable most of the time, but if you rotate the light along its beam axis the artifacts will be visible while they’re spinning.

This thread inspired me to do something I’ve been postponing for a good while: diffuse a headlamp, the $7 one that was a big hit here on the forum. I’ve seen the threads on CPF of someone selling by the sheet and shipping to me killed it. It so happens that my local Dedeman has DC Fix in stock and I picked up a square meter for about 5$, that should suffice for now. I’ve cut it to dimensions and stuck it on the inside of the glass lens to keep a minimum of waterproofing. Below is a beamshot with one headlamp in its original state and one with dc fix applied. Much nicer light to work with in close proximity.


FWIW, I took some comparison shots of two ZL SC52 lights, one stock and the other with DC-Fix Sand on the lens. It’s hard to show the different well in photos due to lack of sufficient color depth, but with a few exposures it seems okay. Here are the results:




I also compared my “brass beauty” light with DC-Fix against a wide-beam SK68, to show why I prefer the brass light for biking. It’s much wider and smoother, and the center of the beam is still brighter than the edges so it does a better job providing even illumination out into the distance. Plus, the 1x18650 light can go much brighter and lasts longer per charge. I had to turn it down pretty far to make a fair comparison in the photo.

I'm very interested in this, but can't see the pictures :(

I recently bought an expensive aspheric lens from Thorlabs that had been treated with 1500 grit to act as a diffuser. It is really a nice beam, but does not throw as far as I had hoped with the diffuser treatment. I just got a couple of cheaper aspherics from china and plan to try to lightly treat it with some 2000 grit to see how that does.

Just curious, but can you post a link(s) to beamshots which approximate what you are trying to do? I’m just not familiar with the whole diffused aspheric concept at all.

Sorry, pics will be back on the 24th. Until then there is a link in the OP to the photo gallery.

-Garry

This happened to me too last week.

[/quote] Just curious, but can you post a link(s) to beamshots which approximate what you are trying to do? I'm just not familiar with the whole diffused aspheric concept at all. [/quote]


I don't have any beam shots and the light is at work right now. I'll try to remember to get some soon.


The concept is simple though. Thor Labs just took 1500 grit sandpaper and roughened up the flat surface of the aspheric. They went a little too far or rough for what I wanted, but it makes for a very nice beam profile.

Hmm . . . Can I do that with a regular glass lens? Another technique to test? I'm going to have to order more lenses!

-Garry