When designing a compact camera, one of the most important components is often the lens.
A smaller lens requires less installation space, allows a smaller opening in the enclosure, and gives designers more freedom when building hidden cameras, 3D-printed cameras and custom DIY projects.
But lens size is only part of the equation. The lens opening, enclosure wall thickness, field of view and distance between the lens and camera board all affect the final design.
At OVOLAPTICS, these are practical considerations we work with when developing compact cameras and 2K DIY camera modules.
How Small Is a Miniature Camera Lens?
A miniature lens can be surprisingly small while still providing a useful field of view.
One compact lens design used with our DIY camera platform measures approximately:
- 8 × 8 mm lens footprint
- 6.5 mm overall height
- 90° horizontal field of view
- 15 cm FPC cable
Each dimension affects the product differently.
The 8 × 8 mm footprint requires very little mounting space, while the 6.5 mm height helps keep the overall camera structure compact.
Despite its small physical size, the lens provides a relatively wide 90° horizontal field of view.
The 15 cm FPC cable is equally important because it allows the lens and main camera board to be positioned separately.
Why Small Lenses Matter for Hidden Cameras
For a hidden camera, the lens should not dominate the appearance of the finished product.
A miniature lens makes it possible to integrate the optical system into a much smaller area of the enclosure.
Importantly, the physical size of the lens is not the same as the size of the visible opening.
An 8 × 8 mm lens assembly does not require an 8 mm hole in the product.
With proper positioning, only a small optical opening is required in front of the lens.
For this miniature lens design, we typically use an opening of approximately:
Ø2.3 mm
This allows the camera to maintain a very small visual footprint while the complete lens assembly remains securely mounted behind the enclosure.
Lens Opening Size Isn't Everything — Wall Thickness Matters
Simply creating a Ø2.3 mm hole is not enough.
The thickness of the material in front of the lens is also important.
A small hole through a thick enclosure effectively creates a tunnel in front of the camera. With a 90° horizontal field of view, the sides of that tunnel can begin to block the lens.
This can cause:
- vignetting,
- dark image corners,
- reduced field of view,
- or partial obstruction of the image.
For our compact 3D-printed and CNC prototypes, we typically reduce the material directly in front of the lens to approximately:
0.8 mm
The entire enclosure does not need to be this thin.
Instead, a recessed lens mounting area can be created from inside the enclosure, leaving approximately 0.8 mm of material around the optical opening.
This gives us an important design relationship:
Lens opening + wall thickness + lens position + field of view
These factors should always be considered together.
Going Smaller: A 1.8 mm Opening on the OVO-C-3
Different camera designs may use different miniature lenses.
The OVOLAPTICS OVO-C-3 Hidden Wall Outlet Camera uses an even smaller lens solution, allowing the optical opening to be reduced to approximately:
Ø1.8 mm
The difference between Ø2.3 mm and Ø1.8 mm may seem small numerically, but it can make a noticeable difference on the surface of a finished product.
A smaller opening can blend more naturally into the surrounding product design and become much less visually noticeable.
This is one of the reasons lens miniaturization matters in hidden camera development.
It isn't simply about making the internal component smaller.
A smaller lens gives the industrial designer more freedom over the exterior of the product.
Why a 15 cm FPC Is Useful for DIY Camera Design
Lens size is only one part of making a camera easier to integrate.
The 15 cm FPC cable provides another important advantage:
The camera board doesn't have to sit directly behind the lens.
The lens can be positioned at the ideal viewing location while the larger 2K camera board is installed somewhere else inside the enclosure.
For example:
Lens at the front → FPC → Camera board at the rear
or:
Lens at the top → FPC → Camera board at the bottom
This can be especially useful when designing:
- 3D-printed enclosures,
- CNC-machined camera housings,
- pet monitoring projects,
- bird-watching cameras,
- robotics,
- smart-home devices,
- and other space-constrained electronics.
The main PCB can also be positioned where there is more room for the battery, antenna, cable routing and ventilation.
This makes the 15 cm FPC an important mechanical design feature, not simply a cable connecting two components.
From Hidden Cameras to 2K DIY Camera Projects
The same miniature lens technology used in compact hidden cameras can also open up much broader DIY applications.
Combined with a 2K WiFi camera module, a small lens can provide the visual input for many custom projects.
For example, a maker could build a custom camera for:
Pet Monitoring
A small 3D-printed camera positioned near a pet bed, feeding area or favorite window.
Bird Watching
A miniature lens integrated into a custom bird feeder or protected observation enclosure.
3D Printer Monitoring
A compact camera and custom mount designed specifically around a printer or other workshop equipment.
Robotics
A small lens mounted at the front of a robot while the main camera board is positioned elsewhere inside the chassis.
Smart-Home Projects
A camera integrated as one component inside a larger custom electronic device.
The advantage is simple:
the project does not have to be designed around a finished camera enclosure.
Instead, the camera can be designed into the project.
Using a 2K Camera Module for AI Vision Projects
A compact camera module can also provide visual input for experimental AI and computer-vision projects.
For example, a bird-watching camera could capture images or video that are then analyzed by a compatible external AI system for:
bird detection, image classification or species recognition.
The same concept could be applied to pets, vehicles, packages, tools or other objects.
The distinction is important:
The camera provides the image. The AI system performs the recognition.
The 2K camera module itself does not need to contain dedicated AI processing hardware to become part of an AI vision project.
This makes compact camera modules useful as flexible image sources for makers experimenting with computer vision.OVOLAPTICS 2K UHD DIY Camera Module
Dual-Band WiFi Adds More Flexibility
Wireless connectivity is another consideration when building a custom camera.
All OVOLAPTICS WiFi cameras support both 2.4GHz and 5GHz WiFi, including OVOLAPTICS WiFi camera modules.
2.4GHz generally provides longer range and better wall penetration, while 5GHz offers additional bandwidth and can encounter less congestion in some environments.
Supporting both gives a DIY project more flexibility when it is moved between different rooms, routers or network environments.
For more details, read:
2.4GHz vs 5GHz WiFi Cameras: What's the Difference?
Don't Forget Heat and Ventilation
A compact enclosure also needs to manage heat.
Video processing, WiFi communication and power circuitry all generate heat during continuous operation.
Certain internal chips or PCB areas in a compact WiFi camera may reach approximately 60–70°C (140–158°F) depending on workload, WiFi conditions, ambient temperature and enclosure design.
This refers to internal component temperatures, not necessarily the external surface temperature.
When designing a custom 3D-printed or CNC enclosure, it is therefore important to consider:
ventilation, internal space, PCB placement and separation between heat-generating electronics and the battery.
The ability to separate the miniature lens from the main PCB using the 15 cm FPC can also help provide more freedom when designing for heat dissipation.
Small Lens, More Possibilities
Miniature lenses are an important part of hidden camera design, but their usefulness goes much further.
An approximately 8 × 8 mm lens footprint, 6.5 mm overall height, 90° horizontal field of view and 15 cm FPC provide a flexible starting point for compact camera projects.
For this lens design, we typically use an approximately Ø2.3 mm optical opening and carefully control the material thickness directly in front of the lens.
Specialized designs can go even smaller. The OVOLAPTICS OVO-C-3 uses a smaller lens solution that allows an approximately Ø1.8 mm optical opening.
Combine miniature optics with a 2K camera module, dual-band WiFi, 3D printing and modern AI tools, and the same basic camera technology can become much more than a conventional camera.
Hidden cameras, DIY projects, bird watching, pet monitoring, robotics or AI vision—the camera provides the image. What you build around it is up to you.
