Meiji MA518 Auxiliary Lens for EMT-1 / EMT-2 — 0.5X Magnification, 108mm Working Distance

The Meiji MA518 is a 0.5X auxiliary (supplementary) lens for Meiji EM-Series stereo microscope bodies that is commonly selected to increase working distance and improve clearance for hands-on inspection tasks. With a published working distance of 108mm, MA518 supports more comfortable part handling, fixture use, and tool access under the microscope—especially in production, cleanroom, and QC benches where ergonomics and throughput matter.

Quick selection note: MA518 (0.5X) is a clearance-first accessory. It widens coverage and increases working distance, while reducing effective magnification—ideal for scanning, assembly support, and rework-friendly stations.

Specifications:

Accessory type: Auxiliary lens (auxiliary objective / supplementary lens)
Magnification factor: 0.5X
Working distance (W.D.): 108mm
Fits: EMT-2, EMTR-2, EMT-3, EMTR-3, EMT-4, EMTR-4
Important note: MA515 adapter is required to use MA518 on EMT-2
Warranty: Limited lifetime warranty (manufacturer-stated)
Country of origin: Made in Japan (manufacturer-stated)

Where MA518 Fits in Cleanrooms and Laboratories (and Why)

MA518 is typically chosen for clearance-driven stereo microscopy: when operators need to manipulate parts, use tweezers/probes, stage fixtures, or inspect larger assemblies without constantly “fighting the working distance.” In cleanrooms, added clearance can also reduce accidental contact events with optics and work surfaces, helping teams maintain better station discipline across shifts.

Typical program fit: scan stations, assembly support, rework benches, incoming inspection, and applications where coverage and ergonomics are higher priority than maximum detail.

For many EM-series programs, facilities standardize a “scan” station with a lower-factor lens (like 0.5X) and a separate “confirm” station configured for higher apparent detail (higher-factor lens or alternate bench).

MA518 Features:

0.5X auxiliary lens designed for Meiji EM-series stereo microscope bodies
108mm working distance to improve clearance and operator ergonomics
Wider field of view and coverage for scanning and orientation
Supports standard bench roles (scan/coverage stations) and stable workflows

MA518 Benefits:

More clearance: better access for tools, fixtures, and gloved handling under the microscope.
Higher throughput: fewer repositioning cycles during scan and handling tasks.
Improved ergonomics: more comfortable posture supports more consistent inspection decisions over long shifts.
Better workflow control: supports scan-vs-confirm station separation to reduce decision drift.

Common Applications:

Assembly support and rework where tools must fit under the objective
Incoming inspection and scan workflows (coverage and orientation)
Larger parts or fixtures where standard working distance is too tight
Cleanroom benches where reduced contact events and better station control are desired

Selection Notes (0.5X vs. Higher-Factor Auxiliary Lenses)

0.5X (MA518): clearance and coverage first—ideal for scan stations and manipulation-heavy tasks.
>1.0X options: selected when defect discrimination and fine detail are limiting constraints; working distance decreases.
Program best practice: standardize bench roles (scan vs confirm) and document lens factor as a controlled station setting.

Optics Cleaning (Recommended for Stereo Objectives & Auxiliary Lenses)

Auxiliary lenses sit close to the work zone and can collect haze, particulate, and handling residues. Use optical-grade swabs and specialty low-lint wipers to maintain contrast and reduce fiber shedding on coated optics.

Link to Meiji MA518 Product Details / Datasheet: Manufacturer Product Page | Datasheet (PDF)

Other Similar Products Available From SOSCleanroom.com

Meiji MA519 Super Widefield 10X Focusing Eyepiece — common bench accessory for focus control and reticle use (model-dependent)
Cleanroom Wipers — support station cleaning and contamination control around microscopes

Notes: Treat auxiliary lens factor as a configuration-controlled input. If different benches use different factors, parts will appear at different apparent size and coverage—driving inspection inconsistency.

Product page updated: Jan. 21, 2026 (SOS Technical Staff)

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The Technical Vault

By SOSCleanroom

Last reviewed: Jan. 21, 2026 | Audience: cleanroom operations, QA/QC, lab managers, manufacturing engineering, EHS

Why 0.5X Auxiliary Lenses Are “Throughput Tools” in Stereo Microscopy

Meiji MA518 — 108mm working distance, scan-station design, and contamination-control benefits of better bench ergonomics

Clearance-driven workflows Scan vs confirm stations Stereo vs compound education

The one-paragraph answer

The Meiji MA518 is a 0.5X auxiliary lens that increases working distance to 108mm on supported Meiji EM-series stereo microscope bodies. In practice, 0.5X auxiliary lenses are selected to improve clearance, coverage, and operator ergonomics—which drives better throughput and fewer handling errors on real benches. MA518 is best treated as a scan-station configuration: wide, comfortable, and rework-friendly.

Compatibility note: MA518 fits EMT-2/EMTR-2/EMT-3/EMTR-3/EMT-4/EMTR-4, and MA515 adapter is required to use MA518 on EMT-2.

Operational problems MA518 helps solve

Cramped clearance: tools, tweezers, and fixtures collide with the objective area.
Slow handling cycles: repeated repositioning to “fit under the lens” reduces throughput.
Operator fatigue: constrained posture increases inspection variability over long shifts.
Contamination-control friction: awkward moves increase glove contact events and accidental touches to optics/surfaces.

Microscopy education: stereo vs. compound microscope engineering

Stereo microscopes are engineered to support inspection and manipulation. They use dual optical paths to provide depth perception, and the system is commonly configured with stands, illumination, eyepieces, and auxiliary lenses to tune the workflow for clearance, coverage, and operator comfort. MA518 is a classic stereo accessory because stereo microscopes are production tools: the optical system is deliberately modular to match real bench constraints.

Compound microscopes are typically optimized for higher magnification analytical viewing (often slide-based) using a single optical axis and transmitted illumination. Their architecture prioritizes objective/condenser performance and optical alignment over tool clearance—making them ideal for analytical microscopy, but not the default solution for hands-on bench manipulation.

Why this matters: Selecting MA518 is a workflow choice—trade some magnification for more clearance and better station behavior, which often improves throughput and reduces handling-driven defects.

Best-practice bench design: “scan” vs “confirm” stations

Many inspection programs become faster and more consistent when benches are assigned roles: a scan station (wide field, high clearance) for coverage and orientation, and a confirm station (higher apparent detail) for borderline decisions. MA518 (0.5X / 108mm W.D.) is typically a scan-station configuration.

Configuration control (minimum recommended fields)

Microscope body model (EMT/EMTR series)
Eyepiece model/magnification
Auxiliary lens factor (MA518 0.5X)
Stand type and typical working height
Illumination type and typical intensity/geometry settings

Optics cleaning and contamination control

Better clearance reduces accidental contact events, but optics still require disciplined cleaning. Use optical-grade swabs and specialty low-lint wipers to maintain contrast and prevent fiber shedding on coated surfaces. Replace swabs/wipers frequently and avoid dragging particles across glass.

Suggested optics-cleaning SOP insert (template-style)

Remove loose particles (blower/air method) prior to wiping.
Dampen a fresh optical swab/wiper with minimal approved solvent.
Wipe gently in one direction; do not scrub with heavy pressure.
Replace the cleaning surface frequently; do not reuse loaded swabs/wipers.
Cover the microscope when idle to reduce airborne deposition.

Helpful links

Source basis

SOSCleanroom product listing context (application positioning and program-fit language).
Manufacturer product page and datasheet for MA518 (0.5X factor, 108mm W.D., fit list, adapter note).
Common inspection microscopy best practices: scan vs confirm workflow design, configuration control, and optics hygiene discipline.

Compliance note: This Technical Vault article is provided for educational support. Always follow facility SOPs, QA requirements, and validation/qualification plans.

Document control: Rev. Jan. 21, 2026 (SOS Technical Staff)