My guess is that due to all of the light hitting one area the material reflects less light over all but I'm not quite sure. I'm guessing you installed a baffle of some kind to prevent light from directly hitting the meter?
An aspheric lens has no spill so that light is “wasted”. When you have the FTT in flood mode it’s so unfocused that it’s almost like not having the lens there in the first place and therefore more light gets though.
Its normal for small diameter zoom-aspheric lights to drop lumens when focus’d like that. The only emitter lumens that make it OTF are the ones that reach the lens. The farther away the aspheric is from the LED, the fewer lumens “touch” the lens.
Found a more consistant way to measure… still need to make a lightbox or meterind tube device… but I need to record these measurements so I’ll post them here.
The readings from a box tend to be very dependent upon the angle the light is shining into the box and where the front of the light is in relation to the opening. I could see well over 50% changes in the readings. With the sphere they are well under 1%.
I painted the inside of my box with a flat white paint. Bare cardboard absorbs different parts of the spectrum differently and can skew the readings since the resulting response curve no longer matches the human eye response.
Yeah doing a bunch at the same time works well, but in a couple weeks I might get odd readings. Still 10 times better than I could estimate without a lux meter.
