I haven't had much luck with led for DF, even when one can get enough light out of them. I am using apos, and the narrow wavelength they provide, limits the information available. I'm not a fan of the heavy blue cast to the image, either. Perhaps that would be of value in reducing extraneous information, with a chromatic aberration prone system.
DF is hard enough to squeeze natural colour from anyway, and leds just make matters worse. Ditto for filtering.
To boot, there is enough negative literature out there about them, that I am cautious about their safety in a blast furnace lighting sort of situation , like a microscope field. They don't even make decent Christmas lights.
We have been through all of this LED crap several times over the years... You know yourself that the big makers use LED lighting in their top of the line stands, yet you continue to talk against them.. Do you just want to stay in the olden times, or can you open your mind and follow new processes???....https://www.leica-microsystems.com/prod ... dm-il-led/
I think one should distinguish between the big makers and hobby microscopysts here, where "hobby" refer to folks that convert their illumination to LED under limited budget contraints, and aim mainly at color photography.
billbillt, the link you posted sets a perfect example. Leica promotes a cell culture microscope, and I believe that a large portion of their market is cell biology microscopy. the leading modality in biology today is fluorescence, due to various reasons. Confocal microscopy is based on lasers anyway. But fluorescence can be done with LEDs as well, since they are fairly monochromatic. So they are fine for excitation. Likewise, DIC and phase can be done successfully with LEDs, when the result is gray scale or pseudo-color. Many research-data images today are "colored" by software anyway. Thus, for up-to-date research, LEDs are fine, and not white light LEDs but especially blue, green, LEDs etc. And these LEDs are quite expensive - hundreds of USD each, for the single wavelength/color.
On the other hand, for us folks who would like just to upgrade an old hobby microscope from the obsolete incandescent or the rare to find halogen lamp, and produce pretty color images, I agree with most of what Apochronaut says, although I am less concerned about UV emission.