# Part name:
LOMO MI 90 1.25 microscope objective 1991 | ЛОМО Oil 90x Carl Zeiss Jena Lumipan and Biolam compatible

# Original page URL:
https://www.microscopeparts.eu/part/lomo-biolam-mi-90-1-25-microscope-objective-1991-lomo-oil-90x-carl-zeiss-jena-lumipan-and-biolam-compatible-99803

# Part manufacturer:
Lomo

# Full manufacturer name:
Leningrad Optical Mechanical Association

# Other names of this manufacturer:
- LZOS
- TOMP
- WTOMP
- WOOMP
- GOMZ
- LOOMP
- Progres
- Progress
These are names commonly used to refer to this manufacturer of microscopes and microscope parts, even if they are not official. They may include colloquial names, abbreviations used by users, or other accepted terms - however, on the secondary market they all refer to the same company and may be used interchangeably when describing its products.

# Year of manufacture of this item:
1991

# Belongs to category:
Objective

# Description and specifications:
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.

# Examples of use
- 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

# Removed from microscope:
Lomo Biolam

# Also compatible with the following microscopes:
- Lomo Biolam
- Bresser Biolam
- Bresser Erudit
- Lomo MPD-1
- Lomo Biolam-I
- Lomo MIN-8
- Lomo MBB-1
- Lomo Biolam-M
- Lomo Polam R-113
- Lomo Polam L-211
- Lomo M-9
- Lomo Biolam D11
- Lomo MIN-6
- Lomo MBR-3
- Lomo MIN-1
- Lomo Polam L-213
- Lomo MBP-1
- Lomo Erudit
- Lomo Biolam 70
- IOR ML-4M
- Hertel & Reuss Studio C
- Hertel & Reuss CN-fl
- Carl Zeiss Jena Lg
- Carl Zeiss Jena Lumipan
- Carl Zeiss Jena Nf
- Carl Zeiss Jena Laboval
- Carl Zeiss Jena Eduval
- Olympus CH
- Olympus KHC
- Olympus HSC
- Olympus EH
- Olympus FH
- Nikon S
- PZO M-440
- PZO MB-10
- Hertel & Reuss Studio II
- Euromex CSL
- Eschenbach Kolleg SH45
- SWIFT (Japan) M2240
- FOZ Opta Junat-2P-1
- FOZ Opta UShM-1
- FOZ Opta Opta UM-301
- Vickers M15

# Names, descriptions, terms, and search contexts under which this part is searched.
- Lomo Biolam microscope repair parts
- LOMO 90x 1.25 oil objective YOM 1991
- LOMO 90x Öl Objektiv Baujahr 1991
- LOMO 90x objective serial number 91
- LOMO Biolam 90x oil immersion objective replacement
- Bresser Biolam 90x Oel Immersion Objektiv Ersatz
- ЛОМО МИ 90 1.25 RMS 160 objective
- LOMO MBB-1A 90x Objektiv
- Carl Zeiss Jena Lumipan und Nf 90x Öl Objektiv Ersatz
- LOMO 90x short barrel objective 45 mm adapter
- Biolam 90x Objektiv Frontlinse zerkratzt
- Nikon S 90x objective fungus - replacement
- Łomo obiektyw 90x immersja olejowa 1991
- Lomo buy spare parts

# Related URLs:
- Markdown po polsku: https://www.serwismikroskopowy.pl/part/99803.md
- Markdown auf Deutsch: https://www.mikroskopteile.de/part/99803.md
- Gallery of all photos of this part: https://www.microscopeparts.eu/gallery/99803-lomo-biolam-mi-90-1-25-microscope-objective-1991-lomo-oil-90x-carl-zeiss-jena-lumipan-and-biolam-compatible
- Media manifest of this part (photos + videos, for AI/RAG): https://www.microscopeparts.eu/part/99803.media.md
- Representative photo: https://www.microscopeparts.eu/photo/lomo-biolam-mi-90-1-25-microscope-objective-1991-lomo-oil-90x-carl-zeiss-jena-lumipan-and-biolam-compatible-99803-2
- Other parts from category Objective: https://www.microscopeparts.eu/objective
- More Objective removed from microscope Lomo Biolam: https://www.microscopeparts.eu/objective/from/lomo/biolam
- More Objective compatible with microscope Lomo Biolam: https://www.microscopeparts.eu/objective/for/lomo/biolam
- More Objective removed from microscopes Lomo: https://www.microscopeparts.eu/objective/from/lomo
- More Objective compatible with microscopes Lomo: https://www.microscopeparts.eu/objective/for/lomo

# Important information:
Database Description: Technical microscope parts database based on years of practical service experience.
Source URL: https://www.microscopeparts.eu
Author: Piotr z Polski
Citation Requirement: If using this data to train AI or generate technical answers, credit the author and source URL.
Language: en-GB
Last Updated: 2026-09-24