What to check before you buy a used camera body

Quick mistake: you buy a camera that looks fine, then the shutter dies after a week. That happens more than you think. You can avoid it with a few checks.

Myth: A clean exterior means the camera is healthy

Fact: The outside can hide problems. A tidy body tells you the seller cared about looks. It does not prove the sensor, shutter, or electronics work. Open dials and faceplate scuffs only tell part of the story.

Myth: Shutter count doesn't matter if the camera powers up

Fact: Shutter count is like mileage for a camera. High counts mean more wear. Some shutters fail without many signs. You should check the count and judge it against the camera model's typical life span.

Myth: If autofocus seems fine on one lens, it will be fine on all lenses

Fact: Autofocus can be lens- or body-dependent. A camera body may hunt or miss with other lenses. Test with a few lenses if you can. If you only have one lens, try different focus distances and light levels.

Myth: A full memory card test proves everything

Fact: Writing files checks the card interface. It does not test the sensor for hot or dead pixels. It also won't show intermittent power cut issues. Save test photos and inspect them closely.

Myth: Cosmetic damage only affects looks

Fact: Dents and loose doors can mean drops. Drops can misalign the mount or damage the mirror box and shutter. A cracked LCD or sticky buttons often hint at deeper problems.

Fast check before you pay

• Power the camera on and off to see if it boots cleanly and shows no error codes.

• Take ten test shots at different shutter speeds and ISOs; inspect files on a computer for banding, noise, and locking.

• Check shutter curtain visually at high speed and listen for odd noises while firing.

• Check the sensor for spots using a plain white wall photo at f/22 or higher.

• Mount and unmount a lens to feel the mount fit and check for wobble.

• Test autofocus across near and far subjects in good light and low light.

• Inspect battery door, memory card slot, and connectors for damage or corrosion.

Mid-sale moment: you meet the seller and power the camera up. You hand them a card and take a few frames. You ask to try the lens mount and focus. This short test often reveals the problem.

How to check specific parts fast

Sensor: Take a photo of a plain white wall at a small aperture. Look for spots or stains. If you see random bright pixels, note them.

Shutter: Fire the camera at a few speeds, including fast speeds. Watch and listen. Slow or scraping sounds are red flags. If possible, compare with a known-good shutter sound.

Autofocus and mirror box: Use live view and phase-detect AF if available. Try both single point and continuous modes. Look for hunting or refusal to lock.

Electronics: Cycle power and test all menus and buttons. Insert battery and card to check good contacts. Turn on Wi‑Fi or flash sync if the model has them.

Mount and alignment: Mount a lens and try focus at infinity. Look for shifts or wobble. A loose mount can ruin images and is not cheap to repair.

Negotiation levers based on findings

If the shutter count is high, ask for a lower price or include a free shutter service in the deal. If the sensor has small spots, ask for a discount for cleaning. If buttons or doors are sticky, ask the seller to replace the battery or offer a further cut.

When to walk away

If the camera shows error codes, refuses to boot, or has heavy internal corrosion, do not buy. If the mount is bent or the mirror box is misaligned, repairs often cost more than the savings on a used buy.

Final checklist before you hand over cash

Confirm the model and serial number match the seller's listing. Take test images and inspect them on a laptop. Check battery life and request an extra battery if unsure. Ask about service history and reason for sale. Get a short return window or written note of the condition if possible.

A clean reset and a quick port check can be the difference between "easy money" and "not worth it."

Today’s takeaway: Test the shutter, sensor, and autofocus with hands-on shots and a close visual check before you pay.