How shutters wear out
Every shutter has a rated mechanical life, measured in actuations. Entry-level DSLRs are typically rated for 50,000 to 100,000 cycles; professional bodies may be rated at 200,000 or more. As the curtains approach or exceed that rating, the timing between the first and second curtain can drift, resulting in partial or uneven exposures. The curtain ribbons can also fray or the blades can warp, which sometimes causes a grinding noise or a complete jam.
What Tim does
Tim checks the actuation count using manufacturer tools or established body-specific utilities. He inspects the curtains for blade damage, ribbon wear, and alignment issues. On bodies where replacement is warranted, he fits a genuine or OEM-equivalent shutter unit and runs a series of test exposures across a range of shutter speeds to verify curtain timing is within spec. For mirrorless cameras the shutter is more compact and the procedure varies by manufacturer, but the diagnostic process is the same.
Common fault patterns by brand
Canon bodies often throw an Err 20 or Err 30 for shutter faults. Nikon DSLRs may show a flashing Err indicator or refuse to power on after a curtain jam. Sony Alpha and Fujifilm X-series bodies can develop curtain warp on the second curtain after heavy use. Tim has experience across all major makes and will advise if a particular body model has a known shutter reliability history.