Uniview UNV turret security camera for CCTV systems in New Zealand

Fixed Lens vs Varifocal CCTV Cameras: Which Should You Specify?

Essential Security Supplies

Choosing between a fixed-lens and varifocal CCTV camera affects field of view, identification distance, commissioning time and the ability to adapt a system after installation. For installers and specifiers in New Zealand, the right decision usually starts with the scene, not the camera brand.

This guide compares active camera examples from FERN360, UniView, TVT and Dahua. It explains where fixed-lens cameras provide a straightforward fit, when varifocal adjustment is worth specifying, and which technical details should be confirmed before equipment is finalised.

For current product options, review the wholesale CCTV and surveillance range or view the relevant products from View our product, View our product, View our product and View our product.

The scene should drive the lens decision

A fixed-lens camera has a predetermined focal length. Once installed, its viewing angle is set by the selected lens, camera position and sensor format. This makes fixed-lens cameras predictable to specify and relatively simple to commission when the coverage area is already well defined.

A varifocal camera provides a range of focal lengths. Motorised models allow the installer to adjust the framing during commissioning, and some models can be adjusted remotely after installation. This is useful when the final mounting position, required identification distance or viewing angle may change during the project.

Neither lens type is automatically better. A fixed lens can provide the right coverage with less complexity, while a varifocal lens can provide more control when distances and scene requirements are less certain.

FGSIP-B2TFSA-28 FERN360 fixed-lens turret camera - wide-angle coverage for entrances and general surveillance

When a fixed-lens camera is the better specification

Fixed-lens cameras are often a strong choice for repeatable coverage zones such as reception areas, retail aisles, office entrances, loading doors and short-to-medium distance perimeter views. When the mounting height and target area are known, a fixed lens can keep the system easy to quote, install and support.

The main specification decision is usually focal length. A shorter focal length, such as 2.8mm, generally provides a wider field of view. A longer focal length narrows the view and can place more pixels on a distant subject, although the exact result depends on the camera sensor and installation distance.

Fixed-lens cameras can also reduce commissioning variables. The installer does not need to spend time adjusting the lens range, and the intended field of view is easier to document for the end user. This can be valuable across multi-camera installations where consistent framing matters.

Current examples in the store include the FERN360 4MP fixed-lens turret kit with a 2.8mm lens, the 6MP UniView IPC3616SS-ADF28K-I1 with a 2.8mm lens, the TVT-D28CL-6MP with a 2.8mm lens, and the Dahua IPC-HDW2541EMP-AS-ANZ with 2.8mm and 3.6mm fixed-focal options.

IPC3616SS-ADF28K-I1 UniView fixed turret network camera - 6MP wide-angle coverage for commercial surveillance

For a fixed-lens camera option, see View our product.

When varifocal adjustment earns its place

Varifocal cameras are useful when the scene has a long viewing distance, an uncertain mounting position, multiple possible framing requirements or a need to balance overview coverage against detail capture.

For example, a camera overlooking a driveway may need a wider view during early design work, then a tighter field of view once the installer confirms the gate position and vehicle stopping point. A 2.7-13.5mm or 2.8-12mm lens range can provide more flexibility than a single fixed focal length.

Motorised varifocal cameras are especially useful on larger projects or installations where access is difficult after the camera is mounted. The installer can set the viewing angle and focus during commissioning without replacing the camera. However, the increased flexibility should be justified by the scene because it may add cost, adjustment time and more commissioning decisions.

UniView’s active IPC3635SB-ADZK-I0 provides a 2.7-13.5mm motorised lens, while the FERN360 5MP motorised turret kit uses a 2.8-12mm motorised lens. Dahua’s DH-IPC-HDBW5442E-ZE is a 4MP motorised vari-focal dome with a 2.7-12mm lens range. The active TVT-D2812-8MP record identifies an 8MP motorised dome with a 2.8-12mm lens range.

FGSIP-C5TMVA-2812 FERN360 motorised varifocal turret camera - adjustable framing for changing surveillance distances

For a motorised varifocal kit option, see View our product.

Fixed lens versus varifocal: practical trade-offs

Fixed lens Varifocal lens
Predictable viewing angle when the scene is known Adjustable framing for changing or uncertain scenes
Straightforward installation and commissioning More flexibility during commissioning
Often well suited to standardised camera layouts Useful for gates, driveways, yards and longer viewing distances
Less opportunity to correct an incorrect field of view after installation Can help fine-tune coverage without changing the camera
Focal length must be selected accurately before ordering The available focal range still needs to match the scene
Good choice where consistent framing matters across multiple cameras Good choice where identification distance is more important than uniform framing

Resolution is only useful when the lens and distance match

Higher resolution does not automatically solve a poor lens selection. A 6MP or 8MP camera can still provide unsuitable evidence if the subject occupies too few pixels, the field of view is too wide, or the camera is mounted at the wrong angle.

When specifying a camera, consider the distance between the camera and the area of interest, the width of the scene, the required level of detail and whether the camera needs to identify a person, read a vehicle plate or provide general situational awareness.

The store data provides useful examples. The UniView IPC3616SS-ADF28K-I1 is a 6MP fixed 2.8mm camera with a listed horizontal field of view of 107.2 degrees and an identify distance of 6.3m. The UniView IPC3635SB-ADZK-I0 is a 5MP motorised varifocal camera with a 2.7-13.5mm lens and listed identify distances from 6.1m to 30.4m, depending on the focal position.

Dahua’s fixed-lens IPC-HDW2541EMP-AS-ANZ provides 5MP resolution with 2.8mm and 3.6mm focal options. Its listed identify distance changes from 6.4m at 2.8mm to 8.5m at 3.6mm. The Dahua DH-IPC-HDBW5442E-ZE extends that choice with a 2.7-12mm motorised vari-focal lens and listed identify distances from 5.7m to 13.1m.

IPC3635SB-ADZK-I0 UniView motorised varifocal turret camera - adjustable field of view for long-range surveillance

For the UniView varifocal option, see View our product.

Low-light performance and environmental protection

Lens selection should be considered alongside low-light performance, infrared distance, dynamic range and environmental protection. A camera with a suitable focal length may still be a poor fit if it cannot handle backlighting, night-time conditions, rain, dust or vandal-prone locations.

The active examples in this comparison include IP67 protection across the FERN360, UniView, TVT and Dahua camera records. The UniView IPC3635SB-ADZK-I0 and Dahua DH-IPC-HDBW5442E-ZE also list IK10 vandal resistance. These ratings should still be checked against the final installation environment, mounting method and manufacturer documentation.

Low-light specifications also vary. FERN360’s fixed and motorised kit cameras list Starlight technology, 0.002 lux colour illumination and up to 30m IR. UniView’s fixed and varifocal examples list LightHunter technology and up to 40m IR. The Dahua fixed-lens example lists up to 30m IR, while the Dahua vari-focal dome lists up to 40m IR.

DH-IPC-HDBW5442E-ZE Dahua vari-focal dome camera - IP67 and IK10 protection for demanding commercial sites

For the Dahua vari-focal dome option, see View our product.

What installers should confirm before ordering

  • Target distance: Confirm where the important subject will be in relation to the camera.
  • Required field of view: Decide whether the priority is broad scene coverage or tighter detail capture.
  • Identification requirements: Check DORI data, pixel density and the intended task rather than relying on megapixels alone.
  • Mounting position: Consider height, viewing angle, glare, backlighting and possible obstructions.
  • Night performance: Confirm IR or supplementary lighting distance and how nearby surfaces may reflect infrared light.
  • Recorder compatibility: Confirm resolution, codec, camera channel capacity, PoE budget and any analytics requirements.
  • Storage: Check bitrate, frame rate, recording schedule, compression and whether onboard Micro SD storage is required.
  • Environmental conditions: Match IP and IK ratings to the mounting location and exposure.
  • Future adjustment: Specify varifocal adjustment when the scene is likely to change or the final framing cannot be confidently confirmed in advance.

For IP systems, it is also sensible to check the selected camera and recorder documentation for interoperability. The ONVIF profiles reference provides a useful starting point when reviewing supported functions and compatibility requirements, but the exact camera, recorder and firmware combination should still be confirmed before project sign-off.

Product Specifications

The following specifications are taken from active product records in the Essential Security Supplies catalogue. Camera performance, lens range and available features can vary by model, firmware and recorder combination.

Specification Detail
FERN360 fixed-lens example Active 4MP Starlight turret camera kit. Fixed 2.8mm lens, 2592 × 1520 output at up to 25 fps, 120dB WDR, 0.002 lux colour illumination, up to 30m IR, 12V DC or PoE, Micro SD support up to 512GB, microphone, metal and plastic housing and IP67 protection. The kit includes a 5-channel NVR with four PoE ports.
FERN360 motorised varifocal example Active 5MP Starlight motorised turret camera kit. Motorised 2.8-12mm lens, 2592 × 1944 output at up to 20 fps, 120dB WDR, 0.002 lux colour illumination, up to 30m IR, 12V DC or PoE, Micro SD support up to 512GB, microphone, metal housing and IP67 protection.
UniView fixed-lens example IPC3616SS-ADF28K-I1 active 6MP LightHunter fixed turret camera. Fixed 2.8mm lens, 107.2 degree horizontal field of view, 130dB true WDR, up to 40m IR, listed identify distance of 6.3m, 12V DC or PoE, Micro SD support up to 256GB, built-in microphone, IP67 protection, metal and plastic construction and operating conditions of -30°C to 60°C.
UniView motorised varifocal example IPC3635SB-ADZK-I0 active 5MP LightHunter turret camera. Motorised 2.7-13.5mm lens, 106.3 to 32.5 degree horizontal field of view, up to 40m IR, listed identify distance of 6.1m to 30.4m, 12V DC or PoE, Micro SD support up to 512GB, built-in microphone, IP67 and IK10 protection, metal construction and operating conditions of -30°C to 60°C.
TVT fixed-lens example TVT-D28CL-6MP active 6MP full-colour turret PoE camera. Fixed 2.8mm lens, 3200 × 1800 maximum resolution, 10-20m white-light view distance, 20-30m IR view distance, 12V DC or PoE, IP67 protection, line-crossing and region-intrusion detection, SMD human and vehicle AI, H.265+ support and a listed two-year return-to-base warranty. The product record states that it does not support P2P, SD card or snapshot functions.
TVT motorised example TVT-D2812-8MP active 8MP motorised dome camera with a 2.8-12mm lens range. The current store record provides the model, resolution and lens range. Confirm the current manufacturer datasheet for IP rating, power, IR distance, field of view and analytics before final project specification.
Dahua fixed-lens example IPC-HDW2541EMP-AS-ANZ active 5MP fixed-focal turret camera. Available 2.8mm or 3.6mm focal options, up to 30m IR, 120dB WDR, 12V DC or PoE, Micro SD support up to 256GB, built-in microphone, IP67 protection and DORI identify distances of 6.4m at 2.8mm or 8.5m at 3.6mm.
Dahua motorised varifocal example DH-IPC-HDBW5442E-ZE active 4MP vari-focal dome camera. Motorised 2.7-12mm lens, 114 to 47 degree horizontal field of view, up to 40m IR, listed identify distance of 5.7m to 13.1m, 12V DC, 24V AC, PoE or ePoE, Micro SD support up to 256GB, IP67 and IK10 protection, metal and plastic construction and operating temperature of -30°C to 60°C.

For full model-specific data, see View our product, View our product and View our product.

Which lens type should you specify?

Specify a fixed-lens camera when the coverage area, mounting position and target distance are already known, especially where consistent framing and simple commissioning are priorities. Specify a varifocal camera when the scene may change, the final viewing angle is uncertain, or the project requires more control over identification distance.

For many commercial projects, the strongest design uses both. Fixed-lens cameras can provide repeatable coverage across standard areas, while motorised varifocal cameras can be reserved for gates, driveways, yards, loading zones and other locations where distance and framing need more adjustment.

The best specification is the one that matches the required detail, distance, lighting and environmental conditions. Start with the scene, confirm the lens range and DORI performance, then verify the camera, recorder and network requirements before ordering.

To discuss a camera selection for a New Zealand commercial security project, review the active FERN360, UniView, TVT and Dahua options or contact Essential Security Supplies for installer-focused guidance.