Zeiss Plan Apo 63x/1.4 oil
![Image](https://photos.smugmug.com/Other/n-xC6Rt/Microscopy/i-PL3hd92/0/b00d4514/L/IMG_5250-L.jpg)
- spring-loaded tip is smaller-diameter than the barrel below so any oil flowing down will get inside the barrel, necessitating the pink hair band to absorb any excess oil.
- the circular groove around the circumference of the tip helps to catch excess oil but only if there isn't too much of it.
- there is a circular depression around the front lens, which I think is meant to catch excess oil and stop it from spreading, but it doesn't seem to work and sometimes traps bubbles under the slide. It also makes the objective very difficult to clean because dirt that accumulates in the depression keeps getting dragged onto the lens when lens paper is pulled across or moved in a circular motion. This causes the use of a lot of lens paper and more wear and tear on the lens caused by repeated cleaning attempts.
Olympus UPLSAPO 60x/1.35 oil
![Image](https://photos.smugmug.com/Other/n-xC6Rt/Microscopy/i-Xjd4CPg/0/baf59ef3/L/IMG_5258-L.jpg)
- The spring-loaded tip is larger-diameter than the barrel, so overflowing oil doesn't get into the barrel but could still make its way down to the nosepiece.
- Easier to clean than the Zeiss because of the relatively large area of flat circular glass that extends beyond the actual front lens. However, at the circumference of the circular glass seems to be a black cement ring that is starting to disintegrate after years of heavy use. The black particles are sticky and adhere onto the front lens or produce streaks across it if the lens paper is pulled across.
Nikon Plan Apo 60x/1.4, 100x/1.45, 100x/1.49 oils
![Image](https://photos.smugmug.com/Other/n-xC6Rt/Microscopy/i-VwhPNw4/0/6a75af7e/L/IMG_5264-L.jpg)
![Image](https://photos.smugmug.com/Other/n-xC6Rt/Microscopy/i-C5xNThV/0/1f28affa/L/IMG_5260-L.jpg)
![Image](https://photos.smugmug.com/Other/n-xC6Rt/Microscopy/i-skkvRMD/0/f7123cad/L/IMG_5263-L.jpg)
- completely flat front tip with no grooves or disintegrating cement, very easy to clean (cleaning these objectives actually feels therapeutic)
- pronounced ridge around circumference of tip is able to catch a good amount of excess oil without having to add hair bands
I am interested to learn from others' experiences on these and other makers' objectives, ways of getting around the difficulties, and reasons for designing the tips in different ways.