How to set up a 4f relay?
Posted: Tue Sep 21, 2021 5:18 pm
I've read about 4f relays and how they allow the externalization/projection of the objective back focal plane. It's a fascinating concept and I certainly see some potential (future) use, which led me to investigate how to actually set one up. Although the concept is pretty easy to grasp, I'm slightly confused about some of the technicalities:
- Can any pair of relay lenses with the same focal lengths (f) be used as long as they are aligned with the BFP, in which f is the distance from the first lens to the objective focal point? Are they required to be aspherical and/or achromatic to prevent visual aberrations?
- How would one integrate such relay in a finite 160mm tube length microscope? I assume designing (and perhaps 3D-printing) some kind of intermediate tube in which the relay lenses can be placed?
- How would you know the distance from the objective BFP to the top of the stand/nosepiece (where an intermediate tube or head would be inserted)?
- Would the process of setting up a 4f relay differ between finite tube length and infinity corrected microscopes?
Thanks in advance!
- Can any pair of relay lenses with the same focal lengths (f) be used as long as they are aligned with the BFP, in which f is the distance from the first lens to the objective focal point? Are they required to be aspherical and/or achromatic to prevent visual aberrations?
- How would one integrate such relay in a finite 160mm tube length microscope? I assume designing (and perhaps 3D-printing) some kind of intermediate tube in which the relay lenses can be placed?
- How would you know the distance from the objective BFP to the top of the stand/nosepiece (where an intermediate tube or head would be inserted)?
- Would the process of setting up a 4f relay differ between finite tube length and infinity corrected microscopes?
Thanks in advance!