Just check ebay once in a while. I've Paid ~30USD / per japan made goniometer. Take care to match nodal points.

Funny. All 3 quoted topics can be found discussed in "Advanced Light Microscopy" released over 35 years ago
Funny, is that you can also find description of Zeiss own, patented Plas-DIC there. And Zeiss quoting the book in whitepaper is even more interesting.

Why is that shiny tip bothering you in the first place?

Dont overdo that iris, best to keep it open. 40x/1.3 is already ~F16
Sole purpose of this, is to allow ~ 1.1 NA darkfield vs 0.95 for dry lens.

Getting rid of coverlsip correction is a bonus

Excessive frames will result of some extra halos and more focused background. Rather minute effect on final output.

Sorry for hijacking the topic. Do those illuminators cover APS-C sensor, or they cause vignetting?

Not worth anything, unless you're scientist and you know what you're doing. IR "effect" is 2 clicks in photoshop of R chanell.
Other effect is depth penetration of light rays. But that's not desirable for epi illumination stacking.

Not mitty NIR, but other dedicated IR optics interests you? Reflachromat (mirror objective) yealds absolutely unusable image in VIS. 0 contrast, CA free tho! Only way i could make it produce an usable image is when mounted to dia microscope with IR pass filter. There are many more aspects that this ...

To answer that question, one would need to find color focal shift response graphs, or at least know lines that objective is corrected for to estimate from theoretical. Ie: https://www.thorlabs.com/images/TabImages/TL2X-SAP_Axial_Color_G1-780.gif I've wrote about that if you're interested: http://www...

Btw, im using Repromasters all the time. Oddly 135mm F9, when focused @ infinity (via my eyeballs) is providing 7x with Nikon 10x, but covers A7RII sensor very well and works in Zerene with alignment and scaling @ OFF, so i assume "telecentric enough". Today's work: http://www.photomacrography.net/f...

Great test Robert, thank you for doing that Sorry for digging up, but i just now started to think about making univerasal tube lens system (no bellows) and sticking to ~100mm tube would make it really eazy for me. Could this phenomenon that Robert discovered be explained by this: 1) Tube lens like R...

Seems like a good replacement for Nikon MM 1x which struggles with APS-C. And aperture is much better.

Telecentric you say... how about coverage and working distance?

Good info, thanks.

What does "COB" stands for?