This is description of this part:
LOMO (ЛОМО) oil immersion microscope objective, 90x magnification, made in Soviet Union / Russia in 1991.
Basic parameters of this objective:
Manufacturer: Lomo, Russia (ЛОМО)
Magnification: 90x
Marking on the objective: МИ 90 1.25 (MI 90 1.25)
Numerical aperture N.A.: 1.25
Serial number: starts with "91"
Year of manufacture: 1991
Tube length: 160 mm
Parfocal length: 33 mm - so-called short barrel objective
Cover glass: yes, 0.17 mm thick
Immersion: yes, oil
Translation: "МИ" stands for "масляная иммерсия", i.e. "oil immersion"
Specimen protection: yes, the objective has a spring-loaded front mount that prevents breaking the slide
Thread: RMS
Why do I state the year of manufacture in the description of this objective? Older LOMO microscope parts (objectives, microscopes, heads) have the year of manufacture encoded in the serial number: the first two digits of the serial number are the year. Many users want to complete their microscope with parts made in the same year as the microscope itself.
This is a so-called short barrel objective with a parfocal length of 33 mm. It is very often mounted on a 12 mm extension, which allows it to be used in microscopes that require objectives with a 45 mm parfocal length. Professional adapters with protective optics, metal adapters and popular DIY 3D-printed adapters all work well here.
Fun fact: LOMO made adapters between the RMS and M27 threads. Thanks to them, this objective was fitted to the Lomo Biolam I and Lomo Biolam M microscopes. Owners of Carl Zeiss Axio series microscopes with M27 thread also took advantage of this and used these adapters.
LOMO objectives are very popular with owners of microscopes from other manufacturers. Due to historical ties, owners of Carl Zeiss Jena microscopes regard them as an obvious replacement for the German objectives.
This objective fits practically any microscope from any manufacturer, as long as it has an RMS thread and accepts objectives with TL = 160 mm and 33 mm parfocal length (or 37 / 45 mm with a suitable adapter). Several example microscopes are listed in the "compatibility" section, but the list is not complete.
What is this part needed for?
- If you want to complete your Lomo microscope with original parts
- If you need a 90x / 100x immersion objective for Lomo, Carl Zeiss Jena, PZO, Olympus or other compatible microscopes
- If you have a Lomo microscope from 1991 (serial number starting with "91") and want period-correct objectives in it
