Monocular, binocular or trinocular microscope: which to buy for your needs

Anyone shopping for a microscope usually knows what it's for: slides in the classroom, smears at the veterinary practice, checking samples in a small lab. Where many people get stuck is a decision that seems secondary: the head. Monocular, binocular or trinocular. It's not a minor detail, because it affects comfort during long sessions, who will be able to use the instrument and whether you'll be able to photograph or project what you see. What the head doesn't decide is magnification or image quality, which depend on the objectives, the condenser and the illumination. It's worth separating the two before you buy.

What changes (and what doesn't) with the head

The head is the part you look through. It can have one eyepiece (monocular), two (binocular) or two plus a third vertical tube for attaching a camera (trinocular). In the Euromex range, the MicroBlue, EcoBlue, BioBlue, BlueScope and bScope series are available with all three heads, so you can choose the head without switching family.

A practical note: within the same series, each version doesn't always come with the same objectives. In BlueScope, for example, the monocular version goes up to 400x, the binocular to 600x and the trinocular to 1000x. When comparing models, always check the objectives, not just the type of head.

Monocular microscope: simple and enough to get started

A single eyepiece, with no interpupillary distance to adjust. It's the most straightforward option for pupils taking turns on the instrument, for children and for anyone observing for short spells. Its limitation is obvious: you look with one eye and, over long sessions, it's more tiring.

There are differences among monoculars that matter. The Microscopio Monocular MicroBlue (400x) is the most basic: a triple nosepiece with achromatic objectives, a WF 10x/18 mm eyepiece, an NA 0.65 condenser and LED illumination with rechargeable batteries, so it can be used cordless. The Microscopio Monocular Ecoblue (400x) steps up to a quadruple nosepiece on ball bearings and an NA 1.25 condenser, with the tube inclined at 45° and a 360° rotating head. If you want something a level higher while staying monocular, the Microscopio Monocular BlueScope (400x) features semi-plan 4x, 10x and S40x objectives, a WF 10x/20 mm eyepiece, a height-adjustable Abbe condenser with iris diaphragm, coaxial focusing with 2 µm precision and 3 W Köhler NeoLED illumination with white light or a halogen-style tone.

Binocular microscope: the comfortable choice for working for hours

Two eyepieces receiving the same image (it isn't 3D viewing like a stereo microscope). The advantage is comfort: observing with both eyes relaxed allows much longer sessions without fatigue. For a lab, a clinic or a hobbyist who spends a lot of time at the microscope, it's the sensible head.

What you need to check is adjustment. On models such as the Microscopio Binocular BlueScope (600x), the head is Siedentopf-type, with tubes inclined at 30°, an interpupillary distance of 48 to 75 mm and ±5 dioptre correction on the left tube, so each user can adapt it to their eyes in seconds. This model adds a fourth semi-plan S60x objective to the 4x, 10x and S40x.

For intensive use, the bScope Microscopio Binocular (1000x) is designed for research in institutes, universities, small laboratories and veterinary applications. It has E-plan objectives, WF 10x/20 mm eyepieces, an NA 1.25 condenser and NeoLED illumination, and its ergonomics are built for long working days: eyepieces with two viewing heights and low-positioned focus and stage controls.

What a trinocular microscope is for

A trinocular is a binocular with a third vertical tube for mounting a camera. It lets you document slides, include images in reports, project onto a screen for the whole class or show a colleague or client what you're seeing without them having to look through the eyepiece. If your work requires images to be recorded, it's the right head.

One thing to check is how the light is split. The Microscopio Trinocular BlueScope (1000x) has a 50:50 trinocular head, which divides the light equally between the eyepieces and the camera tube, so you can observe and capture at the same time. It also has semi-plan 4x, 10x, S40x and S100x objectives, an Abbe condenser with iris diaphragm and 3 W Köhler NeoLED Dual Color illumination. Before you buy, check the product page for what's included and which camera you need for your use.

If you'd like to go deeper into this specific comparison, we have a more detailed comparison of binocular and trinocular microscopes.

When you don't need the most expensive option

More tubes and more magnification don't make a better buy. These are the cases where a simpler option is enough:

• School or first steps in brightfield at 400x: a monocular does the job. For classrooms on a tight budget, the MicroBlue or EcoBlue monocular is more than enough, and the EcoBlue comes out ahead thanks to its NA 1.25 condenser and quadruple nosepiece.
• Occasional photos: if you'll only capture an image now and then, a trinocular isn't essential. A good binocular will give you more everyday comfort for the same investment in optics.
• You don't need 1000x: the 100x objective normally works with immersion oil and only makes sense if you're going to observe very small structures, such as bacteria or fine cellular detail. For plant tissue, protozoa or school slides, 400x or 600x is enough, as on the 600x BlueScope binocular.
• A single user who observes for short periods: a monocular isn't a second-rate instrument; with good optics, like those on the BlueScope monocular, it delivers quality images.

Model comparison table

Beyond the head: what to check on the spec sheet

Condenser

The condenser's numerical aperture affects the resolution you can actually make use of. An NA of 1.25, as on the EcoBlue or BlueScope, lets you get the most out of the higher-magnification objectives; an NA of 0.65, as on the basic MicroBlue monocular, is sufficient for school observation at 400x.

Objectives

Achromatic objectives are the standard across the educational range. The semi-plan objectives on the BlueScope and the E-plan objectives on the bScope are designed to give a flatter field towards the edges of the image, which you'll appreciate when reviewing lots of slides or photographing them. In the BioBlue series, for example, the image stays in focus and centred when you change magnification, as on the Microscopio Trinocular BioBlue (1000x).

Illumination

The Köhler illumination on the BlueScope models provides even light across the whole field, and their NeoLED Dual Color lets you choose between white light and halogen-tone light, which is useful if you're used to the colours of classic stains.

Which microscope to buy for your needs

• Primary or secondary classroom with lots of pupils: the Microscopio Monocular Ecoblue (400x). Monocular, simple and with a quadruple nosepiece and an NA 1.25 condenser.
• University, sixth form or demanding hobbyist: the Microscopio Binocular BlueScope (600x). Binocular comfort, semi-plan objectives and Köhler illumination without paying for a 100x you may never use.
• Veterinary practice or laboratory with long hours of observation: the bScope Microscopio Binocular (1000x), for its ergonomics designed for long sessions and its E-plan objectives.
• If you need to document, project or share images: the Microscopio Trinocular BlueScope (1000x), with a 50:50 light split so you can observe and capture at the same time. If it's going to be used intensively every day, the bScope Microscopio Trinocular (1000x) is the alternative.

All of them are made by Euromex, the Dutch manufacturer for which we are an official distributor, with a manufacturer's warranty of 10 to 15 years and official Euromex technical service in Spain. Shipping is free on all orders to Spain, France and Italy and is dispatched within 24/48 hours. If you're torn between two configurations, we've been advising on microscopy since 2008: tell us what you'll be observing and we'll help you avoid paying more than you need to.