If I could see a production version, and there was some testing done I’d be willing to get on board.
It’s my understanding that sphere size should relate to the lens diameter of the light, ie small lens, small sphere; large lens, large sphere. I’ve read a number of posts here regarding one light giving somewhat different readings in different sized spheres which were both calibrated to one source.
But anyway I’d be interested in a standard ‘BLF’ sphere at that price level. Just no time to make one for myself.
Phil
I would want it to last an hour or two so you can track brightness over time, and lumen sag based on heatup of the head takes longer then 30 seconds and on various modes as well, knowing how long low mode lasts is very useful for an emergency situation light. Fortunately lower modes should have a lot less heat.
Also there is a light reflective coating used in many spheres, i forget what its called but has been mentioned a few times.
Actually large is better to minimize small artifacts instead of magnifying them. Real integrating spheres i have seen photos of are huge, you could fit people in them (if very uncomfortably).
Well I own and operate an electronics manufacturing company with a multi-state dealer network and very happy customers. So don’t worry about my skills.
Sounds like a great idea, especially if it is a BIF (Budget Integrating Sphere.)
I’d get one for a reasonable price.
It’s our ‘BLF’ Integrating Sphere… suggest an alternative size (with a link) and if members like it more, we will switch. Remember that larger might affect packaging and shipping costs a little.
I do not know of any, my point is that larger means less artifact errors
BTW the coating is barium sulfate iirc
Hey Josh, great idea! Put me down for one, please.
yea… There’s a nice used one here for just $2400.00 we’re not pretending to compete with that.
http://www.bmisurplus.com/products/54201-lapshere?gclid=Cj0KEQjwipi4BRD7t6zGl6m75IgBEiQAn7CfF5DijkpvRDI9C7mOIweEMD_t1ptfNxXJBlAA8z1YwNwaAhyb8P8HAQ
Its a nice small(er) size, and i notice there is no direct line of sight from the light source to the sensor.
Yea I planned on that feature too.
I think a BLF IS is a great idea, but a lot more discussion/tweaking is probably going to be needed. Regarding the above, I am not sure that a 15cm IS would be practical/useful, especially with some of the larger (and higher-powered) lights out there. Not to mention, I am guessing that 15cm is an OD measurement, so the actual ID is probably a lot smaller. For those not metrically inclined, 15cm is just a hair shy of 6 inches. You would probably even have issues trying to mount a meter to it. Not to mention, I think the port sizes (source and meter) need to be fairly small in relation to a sphere’s ID, which would be nearly impossible with a 6” sphere used for a variety of different size flashlights. Anyway, good on you for getting the ball (uh, sphere) rolling!
A couple more issues that might be worth discussing/addressing:
- Ideal sphere size/diameter?
- Interior coating?
- Exterior coating?
- Baffle (size/material/placement/etc.)?
- Ports (size/material/placement/etc.)?
- Stand?
Carry on!
obviously the exterior must be coated with 1” thick titanium, how else could we be sure the sphere will resist compression forces from the zombie apocalypse 
I was thinking pre-preg carbon fiber, cured in an autoclave. But yeah, I guess Ti would be OK.
Since this is budget light forum i suppose we can use a not so heavy option :sunglasses:
djozz did a 15 cm one here. Maybe he can comment.
Great idea and I hope this really pans out.
May I suggest that you have some way to make the opening adjustable so that a light as small as a convoy s2 all the way to a acebeam k70 will fit.
15cm would work for small lights and lower lumens, but to use something like a SRK or a large head/High output light, the sphere should be larger. 40cm or bigger. I have seen actual integrating spheres for sale that were "designed for flashlights" and the size was about 12" in diameter, but it was for smaller flashlights. There is information about the size of the entrance port compared to the diameter of the sphere and there are some scientific rules about that. I would just have to go find the info out again.
EDIT:
http://nvlpubs.nist.gov/nistpubs/ScientificPapers/nbsscientificpaper447vol18p281_A2b.pdf
https://www.uleth.ca/phy/naylor/documents/pdf/2008_Noble_reflectance_characterization.pdf
I know there is a bunch more out there, with just a google search
Yes! Yes! Yessss!
I’m in, always wondered why no one on BLF wanted to make a standardized calibrated budget sphere.
Thanks!
Keith
Yay Keith!