Alarm codes: What is your camera display screaming?

The most frequent call to my studio begins with the words of a frightened photographer: * “Master! I pulled the trigger, inside something was grinding, and Err (or F--) was flashing on the top screen! The camera doesn't take pictures. Is it over?”*.

Let's look at how to decipher Nikon's main service messages.

1. Flashing `Err` (System Error) is the main alarm marker!

The message `Err` means that the main processor has detected an **optocoupler mismatch or a mechanical lock**. The sensors did not receive a signal that the shutter cycle or mirror down cycle had completed successfully.

• Reason 1:The shutter curtain has become torn or warped.
• Reason 2:The gears of the mirror drive gear were licked (Mirror Box).
• What to do as a photographer:Remove the battery for 5 minutes. If, when you turn it on again, the message `Err` does not disappear - **do not try to cock the bolt by force!** Take the carcass to the service center.

2. Flashing `F--` (Aperture / Lens Contact Error)

Error `F--` **NOT related to the shutter!** It means a lost contact with the lens processor or an unreleased ring apertures on older D series lenses.

Nikon system error decoding table

Error code on display	The reason is mechanical/electronic	Wizard Actions
`Err` flashes	Jammed shutter or mirror gear	Shutter diagnostics in the service
`F--` lights up	There is no bayonet contact or the D-optics aperture is open	Wipe contacts with alcohol / Fix f/22
`r12` / `r08` flashes	Serial buffer capacity (Not an error!)	Continue shooting (Normal operation)