A security camera lens sets how wide the picture is and how far you can see detail: a short lens such as 2.8 mm gives a wide view of about 100 degrees for close areas, 4 mm gives about 80 degrees for driveways and yards, and 6 mm or longer narrows to about 55 degrees or less to reach farther. Varifocal lenses let an installer adjust between about 2.8 and 12 mm on site, and wide dynamic range (WDR) helps when the scene has bright and dark areas at once, such as a doorway in daylight. At 10 m away, a 2.8 mm lens covers a scene about 24 m wide, a 4 mm lens about 17 m and a 6 mm lens about 10 m. This page explains lenses and gives a table to choose one.
PCBy the Pixl Canada install team. Calculated October 26, 2026. 7 min read.
- Lens angle and scene width table
- Fixed vs varifocal lenses
- WDR and backlight explained
- Choosing a lens for each spot
- Shorter focal length means a wider view and shorter reach. Longer means narrower and farther.
- A varifocal lens is adjustable on site, which helps when you are not sure of the exact view.
- WDR balances bright and dark areas in one picture.
- Match the lens to the job. See also how far a camera can see.
How wide a view does each lens give?
Typical horizontal angles for a common sensor size. The scene width is calculated as twice the distance times the tangent of half the angle. Real lenses vary, so check the datasheet.
| Lens | Angle | 5 m away | 10 m away | 20 m away |
|---|---|---|---|---|
| 2.8 mm | about 100° | 12 m | 24 m | 48 m |
| 4 mm | about 80° | 8 m | 17 m | 34 m |
| 6 mm | about 55° | 5 m | 10 m | 21 m |
| 8 mm | about 40° | 4 m | 7 m | 15 m |
| 12 mm | about 28° | 3 m | 5 m | 10 m |
A wider scene spreads the pixels more thinly, so detail at distance is lower. See how far a security camera can see.
Fixed or varifocal lens?
| Type | Strength | Weakness |
|---|---|---|
| Fixed (2.8, 4, 6 mm) | Simple and lower cost | You cannot change the view later |
| Varifocal (manual or motorized, about 2.8 to 12 mm) | Adjust the view and focus on site or remotely | Costs more |
A varifocal camera is a good choice for driveways, yards and parking lots where the exact framing matters. See types of CCTV cameras.
What is WDR and when do you need it?
| Feature | What it does | When it helps |
|---|---|---|
| WDR (wide dynamic range) | Balances very bright and very dark areas in one picture | A doorway in daylight, a window behind a counter |
| BLC (backlight compensation) | Brightens a subject lit from behind | Faces against bright backgrounds |
| HLC (highlight compensation) | Reduces bright spots such as headlights | Driveways and plates at night |
If your pictures wash out or faces go dark, see picture problems and fixes.
Which lens for which spot?
| Spot | Lens |
|---|---|
| Front door, hallway, small shop | 2.8 mm |
| Driveway, yard, store aisle | 4 mm |
| Long drive, fence line, parking lot | 6 mm or varifocal |
| Gate with plates | Dedicated plate camera. See licence plate cameras |
Security camera lenses: frequently asked questions
What lens is best for a security camera?
It depends on the spot: 2.8 mm for doors and small rooms, 4 mm for driveways and yards, 6 mm or varifocal for long distances.
What does 2.8 mm mean?
The lens focal length. A shorter number gives a wider view.
What is a varifocal lens?
A lens whose view and focus can be adjusted, usually from about 2.8 to 12 mm.
Do I need WDR?
If the scene has bright and dark areas together, such as a doorway in daylight, yes.
Does a wider lens see less far?
Yes. Wider lenses cover more area but give less detail at distance.
Can Pixl choose lenses for me?
Yes. Send photos of each spot. Wired CCTV gets a free written quote. You pay after the job.
Get each camera matched to its spot
Send photos. Free written quote for wired CCTV. You pay after the job.
How high to mount a camera
Types of CCTV cameras
How to choose a security camera
CCTV camera installation
CCTV installation cost
Security camera for business
Sources and method. Scene widths are calculated as 2 × distance × tan(angle ÷ 2), using typical horizontal angles for a common sensor. Actual angles vary by camera.
About Pixl Canada. Pixl Canada is an installation company based in Edmonton, Alberta, serving cities across Canada with TV mounting, security cameras, appliance installation and smart home setup. Call or text (587) 899-7495. Open Monday to Saturday 8am to 8pm and Sunday 9am to 7pm.