How to Clean Thermal Camera Lenses Safely
By clast.com.au | Published: 2026-10-27
Category: Tips & Care
Learn the safe way to clean your thermal imaging camera lens without damaging delicate coatings. Step-by-step guide for models like the LIEMKE KEILER-35 PRO.
Quick answer
Use a soft, dry lens brush or air blower first, then a microfiber cloth with a drop of lens cleaning solution. Never use household cleaners or rough fabrics on thermal camera lenses.
Why thermal lenses need special care
Thermal imaging camera lenses, like those on the LIEMKE KEILER-35 PRO, have delicate anti-reflective coatings that are easily scratched. The germanium or chalcogenide glass used in thermal lenses is softer than standard optical glass, making it more prone to damage from improper cleaning. A single scratch can degrade image clarity and reduce detection range.
What not to use
Avoid paper towels, tissues, or your shirt—these fabrics can leave micro-scratches. Household glass cleaners, alcohol wipes, or any ammonia-based solutions can strip protective coatings. Even some lens cleaning cloths sold for eyeglasses may be too abrasive for thermal optics. Stick to products designed for precision optics.
Step-by-step cleaning process
- 1. Blow away loose dust: Use a rubber air blower or compressed air canister to remove dust and grit from the lens surface. Do not use canned air that contains propellants, as they can leave a residue. Skipping this step can grind particles into the coating when you wipe.
- 2. Brush off remaining particles: Gently sweep a soft camel-hair or carbon-fiber lens brush across the lens in one direction. Never rub back and forth—this can embed debris into the coating. Always brush before wiping to avoid scratching.
- 3. Apply cleaning solution to cloth, not lens: Put one drop of optical-grade lens cleaning fluid onto a clean microfiber cloth. Do not apply directly to the lens, as liquid can seep into the housing and damage electronics. Using too much solution can cause streaks or internal fogging.
- 4. Wipe in a spiral from center outward: Starting at the center of the lens, wipe outward in a gentle spiral motion using the damp area of the cloth. Flip the cloth to a dry section and repeat to remove any moisture. Circular wiping from the center prevents pushing debris into the edges.
- 5. Inspect and repeat if needed: Hold the lens under a bright light at an angle. If streaks or smudges remain, repeat steps 3–4 with a fresh area of the cloth. Do not press hard—let the solution do the work. Stubborn smudges may require a second pass, but never scrub.
- 6. Store with lens cap on: After cleaning, immediately replace the lens cap to protect the surface from dust and accidental contact. Store the camera in a dry, padded case away from direct sunlight. Proper storage reduces how often you need to clean the lens.
Product note
- LIEMKE KEILER-35 PRO Thermal imaging camera (2020): The LIEMKE KEILER-35 PRO features a 35mm objective lens with a 1,280 x 960 LCOS display and 4 color modes. A clean lens is essential to preserve the high-resolution image quality and contrast that this model delivers, especially in low-contrast thermal scenes.
LIEMKE KEILER-35 PRO Thermal imaging camera (2020)
