vinmunoz wrote in post #17175580
How will we know if we have the light leaks issue?
Set to bulb or 30 sec exposure, set the aperture wide open (f1.4~f2.8) and ISO 1600 ~ 6400 (this would be the typical setting for catching night sky without star trail using a ultra wideangle lens, and among the more common camera use, it's probably the most demanding application I could think of in terms of light sensitivity). Put lens cap on the lens and for extra measure, tape the seam or wrap securely with dark cloth. During exposure, shine a light all around the lens mount (small Maglite with focused beam would be best). If the connection between lens and camera is good, the resultant image should be black with perhaps some noise depending on ISO setting and how warm your camera was at the time of exposure. Then again, this is an extreme stress test and DSLRs have been known to fail especially if the viewfinder is not covered. Unless you are using the A7/R for long exposures and astrophotography, I would not be too concerned.
http://www.imaging-resource.com …tain-lenses-under-specifi