So I'm a microscopy streamer/content creator and of course there's nothing quite like DIC to make your microscopy pop for an audience so that's what I run most of the time on my BH2. With the NIC turret, you also get 10/40 phase annuli (perfect for the DPlanApo 10/20x lenses on my other turret) and a brightfield slot. The one painful omission, of course, is darkfield - which is always great for lighting up larger subjects like copepods and hydra. In the past, switching to DF usually had me pulling off my condenser and swapping to the phase contrast condenser which has a dedicated DF position. That means I could never go quickly between the two and it was a big decision to sort of stop the fun for a little while while I changed out the condensers.
Well I was staring at my NIC condenser the other day and realized that I might be able to stick a DF patch stop in the polarizer slider. I had a thin metal sheet stop from an Amscope dry DF condenser lying around and, wouldn't you know it - it's a perfect fit for the empty aperture on the slider! To seat it, I put some pieces of scotch tape just barely sticking out over the aperture. Then I flipped it over, dropped in the patch stop, and pressed it firmly into the overhanging tape. I found that there wasn't enough clearance with the tape initially, so I just trimmed the excess and now it slides perfectly!
In practice it's a little bit touchy - the condenser really needs to be right up against the slide to avoid a dark region in the middle of the FOV, but I can probably address that by making a slightly smaller patch stop. This one successfully gets me DF with the 20x SPA objective (.70 NA) which is great, but I don't know how much margin there is on that - the Amscope condenser is rated for .90 NA so maybe I can take a millimeter off the diameter without issue.
Now obviously I've sort of removed the ability to do "pure" brightfield, but, with just the initial polarizer in place, I still need to add ND filters to avoid blowing out my camera sensor, so I don't consider that much of a problem. Now I've got BF, DF, DIC, and PC all with one condenser and it's sooooo convenient for what I'm doing. I'll try to post some clips later of me switching between all the modes - I feel like a tacti-cool microscopist when I go between each one
![Laughing :lol:](./images/smilies/icon_lol.gif)