So, it ‘stretches’ a really long way.
That means the lens has a long focal length.
That means you lose a lot of light when focussed.
It also means a tight narrow beam with a small projection of the LED.
Received my HT08 today…
Total design faillure… :person_facepalming:
When focussed only –30- 50 of the lens is used because the light from the LED goes through a narrow tube.
The focal distance of the fresnel lens is already very large, so even when 100% of the lens was used when focussed it would be a relatively small amount of light that would be focussed.
To solve this there has to be done some serious machining, and you’ll lose the ability to make a wide flood like you can with the stock set up, because you’ll have to open the head up by removing a considerable part of the threads inside the head.
And then the modes: High - strobe - SOS :person_facepalming:
Yes, only 30% (estimated) 50% of the lens is used when focussed.
Only the centre of the lens receives light form the LED when focussed.
I managed to get the driver into 3 modes though, so that’s okay now.
Some measurements show that 50% of the lens is used when focussed.
That’s significantly better than 30% of course, but still only half of what it should be.
I hope to finish opening the inside of the head today so that 100% of the lens is used when focussed.
I did one very unscientific test but it proves what Jerommel is talking about.
Specs of my HT08:
Dedomed XPL led
Blf Fet+1 driver
Samsung 25R battery
I measured throw twice in a row with same battery one right after another. First test was with light assembled as intended to work, measured intensity was 45kcd.
Next i disassembled the light and took the lens in front of the light like this:
This way the lens will capture as much light as possible. This way the light gave intensity of 113kcd.