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RF detector vs lens finder

Updated: 22 October 2026

You are trying to decide whether the thing you fear is a camera that transmits, a camera that only stores video, or a magnet stuck to the car, and the shop is offering one handheld for all three. An RF detector vs lens finder choice is that split. Radio hears a signal that is on now, including your router. A red window looks for a glint you can see. A magnetic probe reports a magnet, not a named tracker. The model-by-model table stays on the [camera detector comparison](/hub/electronic-surveillance/camera-detector). The twelve amazon.co.uk listings were compared on 21 October 2026. This is not a lab test.

You are trying to decide whether the thing you fear is a camera that transmits, a camera that only stores video, or a magnet stuck to the car, and the shop is offering one handheld for all three.

Our top picks

SIKVIO SIKVIO K18

Best overall

SIKVIO SIKVIO K18
8.8/10about £44.99
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ZHENHAN ZHENHAN S500

Alternative

ZHENHAN ZHENHAN S500
5.9/10about £25.99
View offer
HawkSpy HawkSpy K18

Best value

HawkSpy HawkSpy K18
6.5/10about £40.92
View offer
On this page
  1. 1.RF hears a transmitter, including the router
  2. 2.A lens window does not need a transmission
  3. 3.A magnet is not a tracker
  4. 4.Which listings in this set state which mode

RF hears a transmitter, including the router

RF mode is the right tool when you believe something is transmitting while you search, and the wrong tool as a promise about everything else. A phone, a laptop, a smart speaker, and the hotel router are also transmitters, so the first alarms are often yours. bug-detectors.co.uk's bench note is blunt: those alarms are real radio energy and a false conclusion if you call each one a camera. Lower the sensitivity until the known router is quiet, then see what still changes when you move closer. If nothing changes, you have not cleared the room. The miss is complete when the camera has no radio. A camera that records to a micro SD card, with no wireless link, is invisible to an RF detector, which matches FCDO Services. Stated gigahertz spans on these listings are seller text, not a detection percentage. How to walk the room is on how to use a hidden camera detector.

A lens window does not need a transmission

Use the red or infrared window when the camera may be off the air and you can still see a lens. The glint does not require the camera to be recording at that second, and it fails when the lens is covered, around a corner, or too dirty to return light. Screws, smoke-alarm covers, and glossy plastic glint as well. You then look in normal light for a pinhole, a lens ring, or a card slot. HawkSpy names an infrared viewfinder on the listing. T19 states red-light reflection. Claiming a lens window and having reviewers describe a glint are different evidence. If your worry is a camera recording to a card, do not buy RF alone.
SIKVIO SIKVIO K18

Testsieger

SIKVIO SIKVIO K18
8.8/10about £44.99
View offer

A magnet is not a tracker

Magnetic mode checks for a magnet, usually under a sill, behind a bumper, or in a wheel arch you can reach without dismantling anything. The alarm means a magnetic field. It does not identify a GPS tracker, a brand, or a SIM. Phone mounts, sensors, and ordinary magnets set the same probe off. A quiet probe is not a clear car, because a tracker may be wired or may transmit only when the car moves. Do not pull covers off safety systems. HawkSpy at least lists a GS probe in the box. If the worry is a magnet on the car, a lens window has nothing to glint on under the sill.

Which listings in this set state which mode

Frequency you can point at sits on SIKVIO's specification cell, on Souhpyh's bullet, on Diseleri's 1–6.5 GHz bullet, and on the 100 MHz to 8 GHz bullets of ZHENHAN and CHIRSMIP. HawkSpy, AOBOCAM, KEULGOUL, the FG618, T19, Velnoro, and the BK19 have no frequency row you can quote. None of the twelve is a non-linear junction detector, the professional tool FCDO Services separates from a consumer gadget. The £5.99 Velnoro claims all three modes, and one of two reviews says it alarms on almost everything. The £129.99 FG618 still drew one report of about 3 to 4 inches of RF. Read the hidden camera detector buying guide before you pay. If the camera may be off the air, do not rely on RF alone. If the fear is a magnet on the car, do not rely on a lens window alone.

Common questions

When is RF the right mode?
RF is the right mode when you think a camera, bug, or tracker is transmitting during the search, and you can first quiet the detector on a known phone or router. It reports signal strength.
When does RF miss a camera completely?
It misses a camera that stores video on a card and has no radio, and a camera that is off or transmitting only in a later burst. FCDO Services describes those designs as power plus Wi-Fi or power plus storage such as micro SD.
What does the red window actually show?
A reflection, usually through a red or infrared finder in a dim room. A small glint can be a lens, a screw, a smoke-alarm cover, or glossy plastic.
Why do screws and smoke alarms light up?
The finder reacts to a reflective surface, not to the word camera. Screw heads and curved plastic return the light in the same way a small lens can.
Does magnetic mode identify a tracker?
No. It reports a magnetic field. A tracker case, a phone mount, and a sensor can all set the same probe off.
Which products in this set state a frequency?
SIKVIO states 1 MHz to 6.5 GHz on the specification cell. Souhpyh, Diseleri, ZHENHAN, and CHIRSMIP claim a span in a bullet. HawkSpy, the FG618, and the BK19 do not give a frequency row.
Can you rely on one mode?
Only if your worry is one kind of device and you accept the miss. RF alone fails a card-only camera.

Related pages

Hidden camera hotel room UK

Camera detector

Best hidden camera detector UK: review files first

Hidden camera detector buying guide: match the mode

How to use a hidden camera detector before you walk

Sources

Public UK sources from the digest, retrieved with that digest on 21 October 2026. Prices, stars and review counts are the amazon.co.uk figures stored for these twelve listings, not a live refresh.

  1. Ofcom, rules on using radio equipment (retrieved 21 October 2026)
  2. Ofcom, spectrum enforcement (retrieved 21 October 2026)
  3. Sexual Offences Act 2003, section 67 (retrieved 21 October 2026)
  4. Explanatory notes to section 67 (retrieved 21 October 2026)
  5. CPS voyeurism guidance (retrieved 21 October 2026)
  6. ICO, home CCTV systems (retrieved 21 October 2026)
  7. ICO, surveillance principles (retrieved 21 October 2026)
  8. FCDO Services, detecting hidden cameras at work (retrieved 21 October 2026)