Aquila Rubra
Normal

Not sure about your question. That was addressed in many places. It's the key to higher magnifications.

Thanks for your post. I From what I understand, Rife produced an infinity microscope in 1928, before Reichert brought infinity microscopes into production in the 1930's. However the Rife design has a longer optical path. Why do you think the Rife system used a longer path ?