The engineer's field checklist — before you hand over the cash

In my workshop I've seen hundreds of people who bought "perfectly working" cameras and then showed up three weeks later with a broken shutter, an oily sensor, or a flooded matrix. Almost every case was preventable — if only they'd taken 10 minutes before the purchase.

Here's the complete checklist I give to every customer who asks "what should I check?"

Before the meeting

1. Check shutter count from a file: Ask the seller for a test shot as an original file (.NEF or .JPG, not a screenshot or social media photo). Upload it to Shutter-Mounter.ru — you'll see the exact actuation count in seconds.
2. Check serial number consistency: Ask for the serial number on the body and compare it to the EXIF data. A mismatch means the motherboard was replaced — possibly to reset the counter.
3. Look at the original listing photos carefully: Shiny grip rubber, a scratched mount, worn-down text on buttons — these are all visible signs of heavy use.

At the meeting

4. Shoot at 1/4000s on a white surface: Check for dark banding — a sign of a failing shutter that doesn't close evenly.
5. Shoot at f/22 on a bright sky or wall: Any dark spots or smudges on the image indicate sensor contamination or damage.
6. Remove the lens and inspect the shutter blades: Use a flashlight. Wrinkled, bent, or oil-stained blades are a red flag.
7. Check autofocus on a textured surface: If the camera hunts or misses consistently, the AF system needs calibration or repair.
8. Test all buttons and dials: Sticky, crunchy, or dead controls are a sign of water damage or extreme use.
9. Check the viewfinder and rear screen: Fungus inside the viewfinder eyepiece, dead pixels on the screen, or delaminated coatings.
10. Check the battery contacts: Green oxidation means the battery was stored dead — damages contacts and the battery itself.
11. Mount a lens and listen: Clicks, knocks, or grinding from the mirror box during shooting suggest a worn or damaged mirror mechanism.
12. Test the flash sync port (if present): Connect a flash unit and fire. If it doesn't sync — the contact is dirty or broken.
13. Check the hot shoe: Bent or missing contacts on the flash hot shoe mean the camera was dropped or the flash was mounted forcefully.
14. Inspect the bayonet mount: Hold the lens at a slight angle and gently rock it — any wobble suggests a worn or damaged mount.
15. Shoot a burst series and listen: An uneven rattling or skipping sound in the shutter during burst mode is cause for concern.