8 powerleds are surrounding a plastic cup, giving a nice omnidirectional and dimmable diffused light on the subject.

It is bolted on a BHMJ microscope focusblock and has full travel of 3cm in 1µm increments.
Moderators: Pau, rjlittlefield, ChrisR, Chris S.
EXIF-data tells me it's 1/5 sec@ISO100, 0,0 EV exposure compensation.BugEZ wrote:...How long are your exposures?...
I have to (find and) check the specs, my guess they are 1 Watt and roughly 100 Lumen each , but I'll check this tonight.ChrisR wrote:...Indeed! And what's the output spec for the LEDs?...
Thank you, Keith. First of all I admire your DIY skills and makes me think that everything is possible and buildable.BugEZ wrote:Your setup looks very clean and neat. Once again many thanks for sharing.
Chris, I've been playing with the idea of using those flash-LED's that you find in mobile phones.ChrisR wrote:I've been drooling slightly over these
http://www.luxeonstar.com/Neutral-White ... -wn300.htm
which are 2000 Lumen ( for short periods).
Eight of those would be a significant investment though.
I believe that phone flash leds are usually actually "on" for a few hundred msecs, they are often used by dumping the entire charge of a low voltage supercap through them. Several companies make controller chips which will switch between a low current "torch" mode and a full charge dump strobe. Alas, they are usually SMD devices and a pia to play with at home.canonian wrote:... I've been playing with the idea of using those flash-LED's that you find in mobile phones.
Driving them at low current could be used as focus assist and driving them shortly at full burst would then act as 8 flashlites.
1ms could easily be reached I guess. ...
A nice trick! Very clean.To reduce 'fogging' I use a conical M42 to C-mount adapter as a hood on my reversed enlarger lenses
Chris, we use the blue derivative of these driven at max current for other purposes.ChrisR wrote: I've been drooling slightly over these
http://www.luxeonstar.com/Neutral-White ... -wn300.htm
which are 2000 Lumen ( for short periods).
Eight of those would be a significant investment though.
Just be aware, they generate significant heat and need to be mounted onto a heat sink with a cooling fan.
See: http://www.luxeonstar.com/v/vspfiles/do ... hermal.pdf