New answers tagged video
A point to remember is that the camera enters live view at the currently set (or metered) aperture, then remains there no matter what changes you make, until you either exit live view or take a photo. This means that movies aren't always recorded at the currently-set aperture. Lets say you are in Aperture Priority Mode you set the camera to F5.6 and enter ...
Technically, it still can't change aperture while recording, as the motor who flips its mirror up is the same which changes the aperture. Logically, it wouldn't make sense if it could change it while recording. As far as I know, only recent Nikon cameras have independent motors for each use, like the new D810.
$10 will get you a flash bracket that gives you a coldshoe or tripod thread to the right or left of your camera body. Even cheeper than that is some scrap steel, and a 1/4"-20 bolt.
I suppose there's a simple way. You could bring a measuring tape or a long ruler down with you underwater. Hold the ruler out in front of the camera and observe at what distance does the markings of the ruler become clear. That should give you a fairly accurate measurement of the focusing distance in water.
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