Machine Vision Optics Comparisons

POMEAS optical applications team · Reviewed by Tiger Xie · Published 2026-10-16

Comparisons matter when two options are both technically valid and the decision turns on cost, cycle time or expected accuracy. The pages below put the alternatives side by side on published data and name the conditions under which each one wins.

Where a comparison depends on a fact that no party publishes, such as measured accuracy on a specific part, the article says so instead of asserting a winner.

1. The guides in this index

A. Lens class

• Telecentric vs FA Lens in Precision Measurement: 4 Checks — Telecentricity, edge and same-axis accuracy, depth of field versus part height, and when an FA lens wins: four checks before you specify.
• Zoom Lens vs Fixed Focal Lens for Machine Vision Inspection — Zoom lens vs fixed focal lens trade-offs for inspection systems - FOV flexibility, repeatability and cost - and when each is the right choice.
• Manual vs Motorized Zoom Lens: How to Choose for Machine Vision — Manual vs motorized zoom lens for machine vision compared - repeatability, changeover, cost and control options, with POMEAS LZ series real specs to help you choose.
• What Is Detent Magnification? Detented vs Continuous Zoom Lenses — Detent magnification explained: how mechanical detent positions work on a zoom lens, how detented, continuous and motorized zoom differ, and what detents do not guarantee.

B. Focus and magnification method

• Liquid Lens vs Motorized Autofocus FAQ — Liquid lenses focus in milliseconds with no moving parts; motorized axes travel further and carry more optics.
• Optical Magnification vs Digital Magnification in Machine Vision — Optical magnification puts more pixels on the feature; digital magnification only resamples captured pixels.
• Microscope 400X vs Zoom Lens: Magnification Conversion — 400X is an eyepiece-referenced number; a zoom lens states object-side magnification.

C. Measurement systems

• Flash Measuring Machine vs VMM: Key Differences and Selection — Flash measuring machine vs VMM: how the two differ in principle, accuracy, cycle time, part size, automation and cost of ownership, and how to choose for your inspection...
• Inline vs Offline Optical Measurement: How to Choose — Inline or offline optical measurement? Compare cycle time, accuracy, repeatability and automation to choose the right inspection system.
• Point Spectral Confocal vs Laser Triangulation: Which Displacement Sensor to Choose? — Point spectral confocal vs laser triangulation compared: surface compatibility, repeatability, range, spot size and cost - with a clear decision rule for transparent...

D. Illumination and objectives

• Telecentric Measurement Lighting: Backlight vs Coaxial vs Dark-Field — Choose illumination for telecentric measurement: transmitted backlight vs coaxial vs dark-field, beam-diameter matching, worked examples and the fields to record.
• Fiber End-Face Inspection Lighting: White vs Yellow — White, yellow or blue for a fiber end face?
• APO vs Plan Achromatic vs Achromatic Objectives: Which Does Your Inspection Need? — APO vs plan achromatic vs achromatic objectives: what each correction class fixes, MPO NA 0.055-0.50 and WD 18.9-45.3 mm, plus a resolution reverse lookup.

E. Core parameters often confused

• Working Distance vs Depth of Field in Machine Vision: What Each One Controls — Working distance decides where the lens sits; depth of field decides how much the part may move.
• Object-Side Resolution vs Measurement Accuracy FAQ — A 1.86 micron object-side pixel does not mean 1.86 micron accuracy.

2. How to use this index

Find the comparison that matches the decision you actually face. If two entries both seem to apply, read the one whose decision comes earlier in the project, because later choices depend on earlier ones.

3. Frequently asked questions

Is a telecentric lens always more accurate than an FA lens?

No. It is more tolerant of working distance variation, which is a different property. A standard lens can be accurate in a fixture that holds the part at a fixed distance. Telecentric wins when the part height varies, when the field of view is small, or when measurement must not depend on focus.

Should I choose a zoom lens or a fixed focal lens?

Choose fixed focal when the field of view will not change: fewer moving parts, no repeatability question and a simpler integration. Choose zoom when one station must serve several part sizes or magnifications, and accept that magnification must be set repeatably and that brightness and depth of field move with it.

Manual or motorised zoom?

Manual when the setting is made once at commissioning and rarely touched. Motorised when magnification changes per product or per step, because a stored position repeats in a way a hand adjustment does not, and because it takes the operator out of the cycle.

Does digital magnification replace optical magnification?

No. Digital magnification enlarges pixels that were already captured and cannot recover detail the optics did not resolve. It is useful for display and for measuring features that are already resolved, and misleading if used to claim finer defect detection.

How do I compare two sensors fairly?

Compare object-side performance rather than sensor specifications: object-side pixel size, field of view after magnification, and whether the lens projects a usable image circle across the whole sensor. A larger sensor behind a mismatched lens can deliver fewer usable pixels than a smaller matched one.

Which comparison decides most projects?

In practice the working distance and field of view envelope, because the machine fixes it rather than the lens. Start there, then use these comparisons to choose within the options the envelope allows.

4. Related POMEAS resources

• Machine Vision Optics Selection Guides: Complete Index
• Machine Vision Inspection Application Cases: Complete Index
• Machine Vision Optics Technical Guides: Complete Index
• Machine Vision Optics Calculators and Formulas: Complete Index
• Machine Vision Optics Troubleshooting: Symptom Index
• All POMEAS machine vision knowledge articles
• POMEAS zoom lenses
• POMEAS telecentric lenses
• POMEAS FA lenses
• POMEAS machine vision lighting
• POMEAS Technical Reference Series — full-length notes on optical imaging performance testing and measurement method

Talk to a POMEAS Engineer About the Right Option

If two options both look viable, send the part, the tolerance and the constraints on working distance and cycle time. We can narrow it on the parameters that actually decide, rather than on specification tables.

Email: [email protected] | WhatsApp: +86 185 9810 2007

Reviewed by Tiger Xie.