AmScope 4X Infinity Achromatic Objective - Accurate Color

Our review of the AmScope A4X-INF-B finds it to be a focused, no-frills 4X objective for users who need reliable low-power imaging on infinity-corrected biological microscopes. The single biggest reason to buy is its achromatic correction paired with an infinity-corrected DIN design, which improves color accuracy and edge sharpness at 4X while fitting standard RMS mounts. For labs or hobbyists replacing or expanding low-power objectives, this lens delivers predictable performance with a 45mm parfocal distance and a rugged black finish.

Key Features

• 4X Magnification: Provides a wide field of view and low-power overview imaging that is ideal for scanning slides and locating regions of interest quickly.
• Achromatic Correction: Reduces color fringing and improves color fidelity at edges, producing clearer images for biological observation and documentation.
• Infinity-Corrected DIN Design: Works with infinity optical systems and modern microscope optical trains for consistent performance when used with compatible tubes and condensers.
• RMS Mounting Thread: Uses the standard 20.32mm RMS thread so it will fit most microscopes that accept RMS objectives without adapters.
• 45mm Parfocal Distance: Keeps focus consistent when switching objectives, speeding up workflow during multi-power examinations.
• Durable Black Finish: The black exterior provides a professional appearance and a protective coating that resists routine handling wear.

Who It's For

This objective is suited to biology students, teaching labs, and research users who need a dependable low-power objective for scanning and routine observation on infinity-corrected microscopes. Its RMS thread and 45mm parfocal distance make it straightforward to integrate into existing sets of objectives.

Users who require higher magnification, specialized immersion media, or advanced plan correction should look elsewhere; this lens is a plain achromatic 4X that prioritizes compatibility and accurate color over field-flatening or specialized optical corrections.

Pros & Cons

Pros

• Achromatic design enhances color accuracy and reduces chromatic aberration at low power.
• Infinity-corrected DIN form factor ensures compatibility with modern infinity optical systems.
• Standard RMS thread and 45mm parfocal distance allow easy swapping with other objectives.
• Solid black finish gives a durable, professional look and feel.

Cons

• Not a plan or apochromatic objective, so field flatness and extreme color correction are limited compared with higher-end lenses.

Specifications

Magnification	4X
Numerical Aperture	0.10
Optical System	Infinity
Reference Focal Length	180mm
Mounting Thread	RMS 20.32mm
Parfocal Distance	45mm
Finish	Black

Our Verdict

The AmScope 4X infinity achromatic objective is a practical, value-minded choice for anyone needing a reliable low-power lens on infinity-corrected microscopes. It delivers improved color accuracy and straightforward compatibility with RMS mounts, making it a good buy for educational and routine lab use where plan-level corrections are not required.

Frequently Asked Questions

Will this objective fit my infinity-corrected microscope?
It fits microscopes that accept RMS 20.32mm threaded objectives and are designed for infinity optical systems.

What is the cover-glass thickness for this lens?
The specification lists achromatic correction; the product is intended for standard cover-glass thicknesses used in biological microscopy.

Is this objective immersion or dry?
This is a fixed nosecone, dry achromatic 4X objective intended for non-immersion use.