CCTV Lenses

CCTV lenses are the optical front end of the camera — determining field of view (how wide an area the camera sees), focal length (zoom and distance to subject), aperture (light-gathering ability for low light), and ultimately the practical use case the camera can address. Most modern IP cameras ship with fixed or factory-fitted lenses, but cameras with interchangeable lens mounts (typically box-style cameras, some bullets, specialised models) accept replacement and specialist lenses to match the lens to the install need — wider angle for short-range room coverage, longer telephoto for distant identification, varifocal for adjustable angle without re-mounting. Specifying the right lens means matching focal length to install distance, megapixel rating to camera resolution (low-rated lenses limit the effective resolution regardless of sensor), and aperture to the lighting conditions at the install position.

Security Cameras Australia stocks replacement and specialist CCTV lenses. Every lens is genuine Australian stock with manufacturer warranty.

For cameras that the lenses fit see the main catalogue. For mounting accessories see Camera Mounts & Brackets.

What lens specifications mean in practice

Focal length (mm)

Determines field of view and effective magnification:

2.8 mm and below — wide angle: ~100° horizontal field of view. Suits short-range room coverage, retail floors, large areas where wide angle matters more than distance.
3.6 mm — standard: ~80° horizontal field of view. The most common general-purpose focal length. Typical residential perimeter at 5-10 m.
6 mm — narrow: ~50° horizontal field of view. Suits medium-distance positions (10-20 m) where the wider angle would lose detail.
8-12 mm — telephoto: ~30-40° horizontal field of view. For long-range identification (20-40 m) and corridor coverage.
16 mm and above — long telephoto: narrow field of view for distant identification, ANPR, very long-range work.

Aperture (f-number)

Lower numbers (F1.0, F1.4) gather more light — better low-light performance, useful for ColorVu and low-light positions. Higher numbers (F2.0, F2.8) are more common for general use. The aperture matters most at low-light positions where the lens needs to feed the sensor enough light for usable image.

Megapixel rating

Lenses are rated for the maximum sensor resolution they can resolve. A 2MP-rated lens on a 4K camera limits the effective resolution to 2MP regardless of sensor — the lens can't deliver enough detail to feed the higher-resolution sensor. Match the lens megapixel rating to the camera resolution for best image quality.

Lens mount

CS-mount (most common for box cameras), C-mount (less common, often with adapter to CS), M12 (some industrial and modular cameras), proprietary mounts on selected brands. Confirm the lens mount matches the camera before specifying.

Fixed vs varifocal

Fixed focal length — single field of view set by the lens design. Cheaper, simpler, perfect when the install distance is known.
Varifocal (zoom range, e.g. 2.8-12 mm) — adjustable field of view across the zoom range. Useful for installs where the exact field of view needs adjustment after mounting (variable mounting positions, uncertain install distance). Motorised varifocal supports remote adjustment.

How to match a lens to your install

1. Determine the target distance

Measure or estimate the distance from camera position to the subject (person, vehicle, plate) you want to identify. For room coverage, the deepest point in the room. For perimeter, the typical detection distance.

2. Determine the field of view needed

Wide field of view (3.6 mm or wider) for general area coverage at short range. Narrow field of view (6 mm or longer) for identification at distance where you need detail more than width. Use a CCTV lens calculator (most manufacturers publish them) for precise sizing.

3. Match the megapixel rating to the camera

A 6MP camera needs a 6MP-rated lens to deliver the full sensor resolution. A 2MP-rated lens on a 6MP camera wastes the sensor.

4. Consider lighting at the install position

Low-light or night-time positions benefit from wider aperture lenses (F1.4 or below). Well-lit positions are fine with F2.0+.

5. Fixed or varifocal

Fixed if the install distance is known. Varifocal if the install distance varies or the field of view needs post-install adjustment.

Common install scenarios

Residential front door (3-6 m)

3.6 mm fixed or 2.8-6 mm varifocal. Face-readable resolution at typical entry distance.

Driveway perimeter (10-20 m)

6 mm or 8 mm fixed, or 4-12 mm varifocal. Adequate identification at typical driveway lengths.

Long-range bullet (30-50 m)

12 mm or longer fixed, or 8-32 mm varifocal. Identification at distance for fence lines, large yards.

Retail floor coverage (wide area)

2.8 mm wide angle or fisheye for whole-floor coverage from a single ceiling position.

ANPR / plate-reading positions

Long focal length (typically 12-50 mm depending on distance) plus dedicated ANPR camera with appropriate IR illumination. See ANPR-specific cameras rather than retrofitting general cameras.

Why buy from Security Cameras Australia

Authorised dealer · genuine lenses with manufacturer warranty.
Expert support · advice on lens selection for specific install distances and conditions, megapixel matching, varifocal vs fixed decisions.
Price-match · free shipping · 30-day returns.

Shop CCTV lenses

Browse below, or see all cameras, camera mounts, or specialist cameras (which include ANPR, thermal and other purpose-built optics).

Frequently Asked Questions about CCTV Lenses

Can I replace the lens on any IP camera?

No — most modern IP cameras have factory-fitted or non-removable lenses. Only cameras with interchangeable lens mounts (typically box-style cameras and some specialist bullets) accept replacement lenses. Check the camera spec for "interchangeable lens" or "C/CS mount" before specifying a replacement lens. For cameras with fixed lenses, replacing the camera is the right call rather than the lens.

What focal length do I need for face identification at 10 metres?

Roughly 6-8 mm for face identification at 10 m on a 4-6MP camera. The maths: pixel density on the target's face needs to be approximately 80 pixels across the face for reliable identification per Australian Standards guidance. Focal length × distance × pixel density determines the result. For specific lens sizing, use a CCTV lens calculator or talk to us — the right lens depends on camera resolution, distance, and identification requirement.

What's a megapixel rating on a lens?

The maximum sensor resolution the lens can resolve. A 2MP-rated lens limits effective resolution to 2MP regardless of camera sensor — the lens can't deliver enough optical detail to feed a higher-resolution sensor. For best image quality, match the lens megapixel rating to the camera resolution. Common ratings: 2MP, 4MP, 6MP, 8MP, 12MP. Cameras at 4K (8MP) need 8MP-rated lenses.

Should I get a fixed lens or a varifocal lens?

Fixed if you know the exact field of view needed at the install distance — cheaper, simpler, slightly better optical quality than varifocal at the same price point. Varifocal if the install distance varies, the field of view needs adjustment after mounting, or you want flexibility. Motorised varifocal adds remote adjustment via VMS or NVR — useful for installs where physical access for adjustment is awkward.

Is a wider aperture (lower F-number) always better?

For low-light performance yes — wider aperture gathers more light, useful for night identification and ColorVu-style cameras. But wider aperture lenses also have shallower depth of field (less of the scene in sharp focus) and can be more expensive. For well-lit positions, standard F2.0 lenses are fine. For low-light positions, F1.4 or F1.0 lenses help — at meaningful cost premium. Match the aperture to the lighting at the install position rather than always specifying the widest.