Match's Mods: Homemade Integrating Sphere

129 posts / 0 new
Last post
Sirstinky
Offline
Last seen: 22 hours 15 min ago
Joined: 11/02/2018 - 17:07
Posts: 1626
Location: Vancouver, WA

If you are willing to pay loads of money for shipping from EU, you can get a 50 CM (around 20”) eps ball that makes a fantastic sphere. They’re about $40 US, but shipping will easily be that much. That will handle reflectors up tp 110 mm and many tens of thousands of lumens. I have a 30 cm one I use for testing and it’s great. You need a calibrated light or one of verified outout to set the multiplier for getting your relative lumen values, but once calibrated, you can get very close (5-10%) to the actual output. Djozz has a great tutorial for it on here to where you don’t need a baffle, ND filter or diffuser…you measure the light through the wall of the sphere and that works. Mine is only good for reflectors up to 65mm, so I built a lumen tube. Point is, there are options for integrating devices that don’t cost hundreds or thousands of dollars.

dthrckt
dthrckt's picture
Offline
Last seen: 2 months 4 weeks ago
Joined: 11/08/2011 - 10:11
Posts: 4660
Location: Upstate NY

Thanks. I really should make one some day.

I see people referencing calibrations. I am sure it would take me a long time to catch up on the people and their methods, but would a sphere like that get me at least 5% precision?

If under a couple hundred total cost, time tweaking and learning is my concern, though I can totally see enjoying that process.

Sirstinky
Offline
Last seen: 22 hours 15 min ago
Joined: 11/02/2018 - 17:07
Posts: 1626
Location: Vancouver, WA

It’s worth it in the long run. It took me probably 10 flashlights (including a loaned Makkua calibration light) and several hours of work to get my multiplier/calibration right. You need to test different sizes and types of reflectors, flooders, throwers, different tints and cri to get it dialed in. I found Fenix, Thrunite, and Olight are good samples to test your calibration with since they use constant current drivers for consistency and their factory numbers are pretty trustworthy. I think 5% is a bit far out, but not impossible. Generally, 10% is considered acceptable and totally realistic. Just be patient and take your time, have fun with it.

jon_slider
jon_slider's picture
Offline
Last seen: 4 hours 5 min ago
Joined: 09/08/2015 - 12:20
Posts: 6215
Location: Central North America
dthrckt wrote:
under a couple hundred total cost
https://budgetlightforum.com/node/60100
Texas_Ace wrote:
You will not have to run the lux meter readings through one or more calculations just to see what the lumen reading is, you simply stick the light in there and read the lumen directly on the meter.
dthrckt
dthrckt's picture
Offline
Last seen: 2 months 4 weeks ago
Joined: 11/08/2011 - 10:11
Posts: 4660
Location: Upstate NY

Thanks!

I did find that thread and even asked if TA might build another. The Ace named a decent price for sure, but I said I would pass (for now). He need not wonder, while I learn enough to know what I need.

jon_slider
jon_slider's picture
Offline
Last seen: 4 hours 5 min ago
Joined: 09/08/2015 - 12:20
Posts: 6215
Location: Central North America

there is a vitamin jar lid over the sensor. I calibrated it by adding a couple pieces of printer paper and kleenex, until my meter read, what I though the output of the light I put on it was supposed to be, per manufacturer.

at the time I use a light called a Lumintop AAA Copper Tool, that had a 0.8 lumen low, and I calibrated to that.

later I got an HDS, which is supposedly calibrated to 200 lumens. My meter said 210 lumens, so I added a bit more tissue paper, and viola, bobs your uncle

example of using the light meter to check for output fluctuations (regulation):

The_Flashaholic
The_Flashaholic's picture
Offline
Last seen: 6 days 21 hours ago
Joined: 04/05/2017 - 12:46
Posts: 1318
Location: Wakefield

I’d probably mount a smaller ball to it to house the sensor inside, this will allow you to run huge output into the ball too.

My 4K Lumen Whore Reviews (MS18, X70, MS12, DX80, X80-GT, X45vn etc) - http://www.youtube.com/c/FLASHAHOLIC_TV

dthrckt
dthrckt's picture
Offline
Last seen: 2 months 4 weeks ago
Joined: 11/08/2011 - 10:11
Posts: 4660
Location: Upstate NY

Thanks, I should just start experimenting. Best way to learn anyhow. I do have a cheap meter.

Pages