ModelCalcs.uk
Magnification Calculator — See the Detail
Calculate the magnification power needed for detail work at your scale.
How We Calculate This
Calculates the magnification you need from the smallest detail you must work with, your near vision, and the model scale. The unaided eye resolves about 1 arcminute of arc — roughly 0.07mm at the 250mm reading distance for a young eye, more like 0.15-0.20mm once reading glasses are needed.
Formula
- Minimum magnification = Eye resolution ÷ Detail size (how much you must enlarge a feature finer than the eye resolves)
- Recommended = Minimum × Comfort factor (1.5× gives working headroom)
- Scale floor: 1:144 lifts the recommendation to at least 3.5×, 1:72 to 2.5× — smaller scales pack finer detail
- Working distance ≈ 250mm ÷ Magnification — higher power means the lens sits closer to the work
Frequently Asked Questions
For 1:48 and larger, 1.5-2.5x is usually sufficient. For 1:72, 2.5-3.5x helps with fine detail. For 1:144 or smaller, 3.5-5x is recommended. Your age and vision quality also affect the magnification needed.
The Donegan OptiVisor is the most popular choice. It is a headband-mounted visor with interchangeable lenses from 1.5x to 3.5x. It keeps both hands free and has a good working distance. LED-lit versions are available.
Higher magnification means shorter working distance — the lens must be closer to the work. At 5x, working distance is only about 50mm, making it hard to get tools in. 2-3x gives a comfortable 80-120mm working distance for most modelling tasks.
Desktop magnifying lamps (typically 1.75-3x) are excellent for general assembly and painting. They combine light and magnification. For very fine work, supplement with a clip-on loupe for additional magnification as needed.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.