Dead Pixel on Camera Sensor

A display dead pixel is a broken pixel on your screen. A camera sensor dead pixel is a broken photosite on your image sensor — it appears in every photo you take, at the exact same position, regardless of what you're photographing.

Camera sensors (CMOS and CCD) are arrays of photosites that capture light. When a photosite fails, it either outputs maximum signal (appearing as a bright white or coloured dot) or no signal at all (appearing as a permanently dark dot). Either way, it shows up in every image at identical coordinates.

It's important to distinguish between dead pixels and hot pixels:

• Hot pixels — appear bright only during long exposures or at elevated sensor temperatures. They are caused by thermal noise from the sensor circuitry and are most visible at slow shutter speeds (2 seconds or longer) and high ISO. Hot pixels may not be present in fast, daylight shots.
• Dead pixels — always present regardless of exposure settings, shutter speed, ISO, or temperature. A true dead pixel appears in a short daylight shot just as reliably as in a 30-second night exposure.

To distinguish them: take two identical shots of a neutral background — one at 2+ seconds exposure, one at 1/1000s. A hot pixel appears in the long exposure only. A dead pixel appears in both at exactly the same position.

The standard test method for identifying sensor dead pixels and hot pixels:

1. Cap test (dead pixel identification) — Fit the lens cap. Set your camera to Manual mode, aperture F/8, ISO 100, shutter speed 2 seconds. Take the shot in a dark room. Open the image and zoom to 100% (1:1 pixel view). Any bright white or coloured dots are either dead pixels or hot pixels.
2. High ISO test (hot pixel confirmation)— Repeat the same shot at ISO 3200 with the same 2-second exposure. Hot pixels appear at high ISO; dead pixels appear at both ISO 100 and ISO 3200. If a dot appears at ISO 3200 but not at ISO 100, it's a hot pixel — more manageable in post.
3. Fast exposure control — Take a shot at 1/1000s, ISO 100, lens cap on. Any dots that appear in this shot too are confirmed dead pixels (not temperature-related hot pixels).

RAW vs JPEG:Always test in RAW format. Most cameras apply in-body noise reduction to JPEGs that removes hot pixels — testing with JPEG can mask defects. Open the RAW file directly in Lightroom, Capture One, or your camera manufacturer's software at 100% zoom.

Most cameras include a built-in pixel mapping (also called dust deletion or sensor calibration) tool. This process scans the sensor, identifies defective photosites, and stores their locations in the camera's firmware. During image capture, the camera replaces the defective pixel's output with an interpolated value from surrounding pixels. The physical pixel is not repaired — it is hidden.

Run pixel mapping before pursuing a warranty claim. Many apparent dead pixels are hot pixels that pixel mapping successfully mitigates.

• Canon EOS R series— Menu → Maintenance → Pixel Mapping. Requires a fully charged battery and a few minutes of warm-up time at room temperature. On older Canon models (5D Mark III, 6D series): Menu → Setup → Sensor Cleaning → Manual Cleaning (then run the pixel mapping option).
• Nikon Z / DSLR— Menu → Setup → Pixel Mapping. Available on most Nikon Z-mount mirrorless and D-series DSLR cameras. Requires battery above 60% and is performed at room temperature.
• Fujifilm X-series — Fujifilm does not offer a built-in pixel mapping feature on X-series cameras including the X-T5. Dead pixel mitigation on Fujifilm requires post-processing software or a warranty claim.

Run pixel mapping after the camera has been at room temperature for 5–10 minutes. After the process, repeat the cap test (ISO 100, 2 seconds) — most hot pixels will no longer appear. If dead pixels remain, proceed with the software fix or warranty claim below.

Sensor dead pixels have several known causes:

• Manufacturing defects — the most common cause. Individual photosites fail to form correctly during sensor fabrication. These appear from the day the camera is used.
• Cosmic ray strikes — high-energy particles from space can damage individual photosites. This is rare but documented — astrophotographers doing long-exposure imaging at high altitude have reported new dead pixels appearing mid-session. Once a photosite is struck, the damage is permanent.
• Heat and thermal stress — extended long-exposure sessions generate sensor heat. Most hot pixels from thermal stress are resolved by pixel mapping, but sustained high temperatures over months and years can permanently damage photosites.
• Age and sensor degradation — all sensors degrade over time. Cameras used heavily for long-exposure astrophotography or timelapse tend to develop more dead pixels than standard use cameras over the same period. This is expected behaviour, not a manufacturing defect, and is generally not covered under warranty.

Canon, Nikon, and Fujifilm all offer 1-year limited warranties covering manufacturing defects. Coverage for sensor dead pixels depends on cause and quantity:

• Manufacturing defects — present from purchase, or appearing early in use — are typically covered. A cluster of dead pixels or multiple defects across the sensor strengthen the manufacturing defect case.
• Natural degradation and heavy use— not covered under standard warranty. If you're an active astrophotographer with 1,000+ hours of long exposure work, sensor degradation is considered normal use.
• Single isolated dead pixel — coverage varies by brand and region. Canon tends to be more flexible on premium bodies (R5, R6 Mark II). Nikon and Fujifilm assess case-by-case.

Document the defect with sample images in RAW format before contacting support. Include images at ISO 100, ISO 3200, and the fast exposure control shot to demonstrate it is a true dead pixel and not a hot pixel that pixel mapping can resolve.

If pixel mapping doesn't eliminate the defect, post-processing software can hide it in your images and video. This is a permanent mask applied in your editing workflow, not a camera-level fix.

• For video work, see the guide to fix dead pixels in DaVinci Resolve — DaVinci's tracker-based approach works well for moving footage.
• For motion graphics pipelines, see how to remove dead pixels in After Effects using the clone stamp and content-aware fill.
• For still photography, Adobe Lightroom's Spot Removal tool and Capture One's Heal tool can mask a dead pixel position. Lightroom allows you to save the correction as a preset and sync it across an entire shoot.

Post-processing fixes are most practical for photographers and videographers with a consistent dead pixel location in a neutral area of frame. For a pixel in the centre of the frame during critical work, a warranty claim or sensor service is the better long-term solution.

If you also need to test a camera monitor or EVF screen (not the sensor), the dead pixel test tool works on any display. Testing a SmallHD, Atomos, or other camera monitor for dead pixels? camera monitor dead pixel test at MonitorTest.pro works on external monitors.