Nikon has just issued a service advisory for owners of the D750 DSLR, specifically those manufactured in October and November of 2014. The shutter in affected bodies has been shown to "not function normally," sometimes resulting in shading of a portion of images. Nikon will repair affected cameras free of charge, even those with expired warranties. There has been no official word yet on whether grey market bodies are eligible for the service as well.
This is the second service advisory for the already well loved D750. You may remember the issue announced earlier this year where shooting with a bright light source could result in a strange glare shape on your final image. This new issue seems to be limited to a smaller number of bodies, but Nikon has set up a link where you can check your serial number to see if it falls in the range of affected cameras.
Your serial number can be found on the bottom of the camera body, as shown in the below image.
Read the full announcement from Nikon below:
To users of the Nikon D750 digital SLR camera - possible image shading from shutter
It has come to our attention that the shutter in some Nikon D750 Digital SLR cameras manufactured in October and November of 2014 may not function properly sometimes resulting in a shading of a portion of images taken with the D750 camera. To correct this issue, Nikon will service these affected D750 cameras free of charge as indicated below.
For those who have already purchased a D750 and would like to have their camera serviced to correct this issue, Nikon service centers will service cameras as indicated below. We sincerely apologize for any inconvenience this issue may have caused.
Identifying affected D750 cameras
To check whether or not your D750 camera is one of those that may be affected by this issue, click the Check Your Serial Number button below and enter your D750's serial number as instructed. If your D750 camera is one of those that may be affected, instructions for obtaining service will be displayed. If your D750 camera is not one of those to which this issue may apply, rest assured that service to your D750 camera as to this issue is not necessary, and you may continue using your D750 camera without concern for this issue.
If your D750 camera is affected, as confirmed with the serial number check above, you will be provided with the necessary information to obtain service to correct this issue free of charge. Once your D750 camera is received by Nikon, your D750 camera’s shutter will be examined and replaced, and your D750 camera returned to you free of charge, even if your D750 camera warranty has expired.
We sincerely apologize for any inconvenience this matter may have caused you.
Please be assured that Nikon is continuously working and taking measures to further improve the quality of its products. Once again, thank you for choosing Nikon for your photographic needs.