I have been experimenting with different objectives lately. The recommended 40x Plan objective with the f50d13.stl works very well. Finding an inexpensive 60x with the same characteristics is a challenge. So I decided to experiment with a cheap 60x I found on amazon. The problem is that this objective is shorter so to make this one work I had to use a longer optics module to compensate for that.
The images I am getting are a little fuzzy, and I am wondering if the tube length is the culprit. I will appreciate your comments and suggestions. Thanks
Do the specifications state the par-focal distance? If it is not 45mm it is most likely to be 35mm. There are notes on how to create optics modules for 35mm par-focal objevtives in the customisations and alternatives section of the assembly instructions. That should help to do other distances as well if necessary. For a 60× lens the lens body from the shoulder of the RMS thread will be less than 1mm shorter than the par-focal distance as the working distance is very short.
it is 45mm
Specification:
| Item Type: | Achromatic Objective |
|---|---|
| Model: | 60/0.85 |
| Material: | Brass |
| Use: | Microscope Accessories |
| Interface Size: | Approx. 20.2mm / 0.80in (International Standard RMS Size) |
| Magnification: | 60X |
| Numerical Aperture: | Approx. 0.85mm / 0.03in |
| Cover Glass Applicable Thickness: Approx. 0.17mm / 0.007in | |
| Microscope Applicable Mechanical Tube Length: Approx. 160mm / 6.30in | |
| Working Distance: | Approx. 0.53mm / 0.02in |
| Common Rail Distance: | Approx. 195mm / 7.68in |
| Parfocal Distance: | Approx. 45mm / 1.77in |
| Spring: | Yes (Automatic Rebound) |
| Package List: | 1 x Achromatic Objective; 1 x Storage Box |
Well, if it will not work with the standard optics module then it seems to be not actually made to that specification. What is the physical length of the objective, from the shoulder of the RMS thread?
The working distance is given as .53mm, so the objective should be about 44.5mm long.
As it is:
Parfocal Distance: Approx. 45mm
Mechanical Tube Length: Approx. 160mm
It should work fine, if it really has those specs.
I’m not sure what is meant by “common rail distance”?
Do you have a manual microscope you can switch the lens into and see if it focuses? And if it does whether the parfocal distance is 45 when it does?
