When using the self timer or remote release it is recommended to remove the viewfinder eyepiece cup and attach the DK-5 eyepiece cap.
This will prevent light entering the viewfinder from affecting the exposure in auto exposure modes.
Reviewed by 2 customers
Using a cable release and a long exposure, I discovered lots of light getting to the sensor/ I was out and about and without access to the DK-5.... not v elegant but a thumb over the viewfinder worked pretty well.
I thought this would be a useless accessory until I read in the user manual: "[When taking photos without your eye to the viewfinder, remove the DK-20 rubber eyecup and insert this DK-5 eyepiece cap to prevent light entering via the viewfinder interfering with exposure.]"--- If you switch to live view I think DK-5 has no function because the mirror in the camera flips and blocks out light from the eyepiece anyway.