firetiger wrote:
D7100 User's Manual
'When taking photos, without your eye to viewfinder, remove the DK 21 rubber eyecup and insert the supplied DK 5 eyepiece cap as shown. This prevents light entering via the viewfinder interfering with exposure'.
Is this stray light entering the viewfinder really a problem? If it can be a problem as I never use the viewfinder, under what conditions should I insert DK-5 cap and/or just leave it on all the time?
You are likely ok with most photos. Long exposures increase the likelihood of stray light entering via the viewfinder