WTS: Calibration lights for DIY integrating spheres / lumen tubes - 67 € -

BLF Special Edition Products
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I’m impressed that M4DM4Xs light meter will read both the cool neutral white perfectly. My LX133 has a bit of a variation between

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I asked him about this as well. He has different lights. His S2+ is using an SST-20 in 4000K and the blf 348 has a 219C in 5000K. So they are much closer in cri and color temperature than Maukka’s earlier lights. This explains why they both read so closely to spec.

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i hope with a calibration "in the middle" (4-5000k) the error towards lights outside that window is small

i will not say my numbers are carved in stone - but a "as good as posssible" field-test

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Since your setup for high cri and NW, I would say your reading the lower end of the spectrum and are fine for WW and NW. If you measure low cri CW I would subtract about 5%. I think this is the number we found using the HS1010A like you have.

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I am interested, and I pm you today already.

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OK, I just ordered lights. Thank You “maukka” :+1: for your hard work and dedication providing us with these Calibration Lights. :+1:
Now I need a suggestion on plans to build a lumen tube. :question: :slight_smile:

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See this thread Texas_Ace BLF Calibrated Lumen tube

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Thanks ” shirnask “. I looked thru some of it and no luck yet finding the details. Not sure it matters if the joints were caulked and the inside painted with some flat reflective paint or just wiped with acetone to take the shine off the inside. Would a 6” pipe change readings. Things like that. I will keep reading thru it, not finished yet. I like the one MADMAX had in his video, it was 6”, probably do a tread on it soon.
:+1:

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:+1:

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I’m interested in the ” Interest list for Convoy C8+ 219C 4000K CRI90: a throwier option for calibration “.

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I would be interested in a CW thrower option… if possible… no hurry…

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Hi guys,

After a little break from the lumen measuring game, I have binned the crappy old lumen tube I made, and built myself an integrating sphere.

One 25cm polystyrene ball from Amazon and about an hour of my time later, and this is what I have crafted:

What the photos don’t show is some paper over the inside of the entry holes to bring the light level down a bit, as higher powered torches were saturating my meter.

It does appear that my meter’s accuracy is biased toward cool white as previously discussed, but when using the correction factor from my calibration S2+ for CW lights the figures appear spot on:

Olight M2R NW - 18800 lux - 0.08 cf - 1504lm
Olight X7R - 132000 lux - 0.08cf - 10560lm
Astrolux C8 - 14100 lux - 0.08 cf - 1128lm
BLF A6 w/ spring bypass - 20300 lux - 0.08cf - 1624lm

For warmer lights the correction factor from my calibration BLF 348 (0.07) was too low. I have considered a few lights which have consistent “known” lumen outputs and decided that a CF of 0.094 appears to work for now. This gives me the following:

Emisar D4s (XP-L HD 3D) - 51300lux - 4822lm
Emisar D4v2 (SST-20 5000k) - 45300lux - 4258lm
Emisar D18 (SST-20 5000k) - 148600lux - 13968lm
BLF FW3A (XPL HI 7A) - 28600lux - 2688lm
BLF Q8 (XPL HD 3D, bypassed springs, brass screws) - 66100lux - 6213lm

I know this is all going to give rough figures but I believe at this point I can at least be fairly accurate with my readings?

Is there anything I’m doing wrong or particularly need to improve?

Thanks!

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That looks pretty similar to a JoshK Sphere. You probably want a filler panel that can go around your smaller lights and has a reflective panel to keep light in.

Mine is only good for about 900-1000 lumen before the meter gets saturated, but you can use a neutral density filter for higher powered lights.

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I’ve actually been using some foam that I’ve cut to shape to stuff in the input hole which I use for small lights but just didn’t photograph it.

I have used some white paper over the holes to reduce the light saturation and might double up on it a couple more times. Is this acceptable as a cheaper (!) alternative to an ND filter?

Thanks!

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White paper is probably fine but it will age and it’s not very durable. If you take care to keep it in good condition and not adjust it then it should be OK.

As JasonWW was trying to explain: Try white paper or foil on the underside of your foam and re-test a small light. I’d bet your readings will change some due to the foam absorbing some of the light instead of “integrating” it back into the sphere.

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Thank you - I’ll do some fiddling. Maybe I’ll make some little white cardboard inserts for various head sizes.

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Please put me down for one. Thanks!

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Five sets of 2x S2+ (CRI95 SST20 & CRI70 XM-L2) have arrived. I’ll have them ready to go soon.

If you need a thrower for integration testing, PM me. Shipping them internationally is expensive.

Unfortunately due to PayPal fees, shipping and more frequent customs charges I’ve had to raise the price from 64 € to 67 €.

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The new batch is now measured and ready. 3 sets of lights are still available.

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Hi hcanning, how is your sphere performing, specifically at higher output levels? Reason I ask is that I am seeing inconsistency with mine between lower lumen levels and higher lumen levels as posted here. I see your sphere has a complete opening at the luxmeter rather than just being pressed up against the foam like mine is (see pics of mine posted here). I also am not using any diffusion material in mine, nor am I blocking the entrance hole with anything other than the light itself (and maybe part of my hand at times. I need to figure out what I’ve done wrong with my sphere and how to correct it for more trustworthy results.

Thanks,
-Garry