Introduction
When you insert an endoscope into a pipe, engine cylinder, or body cavity, you naturally hold the tip at some distance from the object. That distance – from the lens to the target – is called the working distance. It is a key specification of any endoscope camera module, because it affects image size, brightness, and sharpness. This article explains what working distance means, how it relates to focusing range, and what typical values to expect.
What Is Working Distance?
Working distance is the distance between the tip of the endoscope and the surface being inspected. Unlike focusing range (which describes the span of distances that stay sharp), working distance is the specific value where the image is optimally sharp. For a fixed‑focus endoscope, the lens is set to a hyperfocal distance, and you can work anywhere within the depth of field.
For example, a micro endoscope camera module for blood vessels may have a working distance of just 1–5 mm. A general‑purpose 1080p endoscope camera module might work well at 30–80 mm.
Why Working Distance Matters
Magnification – Get closer to see tiny details.
Illumination – LEDs are brightest near the tip; longer distances need more light.
Focus – The object must sit within the focusing range to stay sharp.
Access – Tight spaces may force you to work at a specific distance.
A hd camera module with a wide focusing range gives you flexibility, but the intended working distance should guide your lens choice.
Typical Working Distances by Application
| Application | Typical Working Distance | Reason |
|---|---|---|
| Medical laparoscopy | 30–100 mm | Operating space in abdomen |
| Medical arthroscopy | 5–50 mm | Close to cartilage |
| Industrial borescope | 10–80 mm | Engine cylinders, valves |
| Consumer USB endoscope | 20–100 mm | Versatile DIY use |
| Micro endoscope | 1–5 mm | Very small, high magnification |
| Pipe / sewer inspection | 50–200 mm | Camera centred in large pipe |
Working Distance vs. Focusing Range
Focusing range (depth of field) is the range over which the image stays acceptably sharp. For instance, an endoscope camera module might have a focusing range of 10 mm to 100 mm. Any object placed between those distances is in focus. The working distance is where you actually place it; you can choose any distance within that range.
A 1080p endoscope camera module with a wide focusing range (e.g., 8 mm to infinity) lets you work at 20 mm, 50 mm, or 200 mm without losing sharpness. A micro endoscope camera module may have a narrow range (2–10 mm), so you must position the tip precisely.
How Focal Length and Aperture Affect Working Distance
Short focal length (wide angle) – Gives a wider focusing range, so working distance is less critical.
Long focal length – Narrows the focusing range, requiring more accurate positioning.
Large aperture (small F‑number) – Reduces focusing range, making working distance more critical.
Small aperture (large F‑number) – Increases focusing range, offering flexibility.
For a fixed‑focus cmos camera module, designers often use a short focal length and moderate aperture (f/2.4–f/2.8) to achieve a wide focusing range, allowing comfortable work from 15 mm to 150 mm.
Choosing the Right Working Distance
| Your Task | Recommended Working Distance |
|---|---|
| General pipe / wall inspection | 20–100 mm |
| Engine cylinder inspection | 10–50 mm |
| Electronics / PCB inspection | 5–20 mm |
| Medical laparoscopy | 30–100 mm |
| Micro‑surgery | 2–10 mm |
| Long‑distance sewer inspection | 50–200 mm |
Working Distance in USB Endoscope Cameras
A USB Camera Module (UVC compliant) is often designed for a working distance of 20–80 mm – ideal for DIY and professional inspection. Some models include a manual focus ring to adjust the working distance precisely. For example, a 1080p endoscope camera module with a 5.5 mm diameter and fixed focus at 30 mm is very common.
Sincere’s Endoscope Camera Modules
At Sincere, we manufacture endoscope camera module products with customisable working distances:
Endoscope camera module – Focusing range matched to your typical working distance.
USB Camera Module – UVC compliant, fixed or adjustable distance.
Focusing Range – From 2 mm macro to infinity, tailored to your application.
Hd camera module – 720p/1080p modules optimised for your work distance.
Cmos camera module – High‑sensitivity sensors with appropriate optics.
Micro endoscope camera module – Ultra‑compact, short working distances (2–20 mm).
1080p endoscope camera module – Full HD resolution with precise distance setting.
Summary
The working distance of an endoscope camera is the distance from the lens to the target you want to inspect. It must fall within the focusing range of the endoscope camera module. Short distances give higher magnification but a smaller field of view. Long distances cover more area but need brighter light. For most industrial and consumer tasks, a working distance of 20–100 mm works well. For medical micro‑endoscopy, a micro endoscope camera module with a 2–10 mm distance is required. When selecting a USB Camera Module or a 1080p endoscope camera module, check the focusing range to ensure your typical working distance is covered.
Contact Sincere to discuss your endoscope camera module and working distance requirements.
