Long Exposure Calculations
Saturday, November 21, 2009 at 9:40 We'll be heading out for some night photography next month. Playing with long exposures is one of the thing you can't get around. Especially since I don't have any f/0.2 lenses in my bag.
Most lenses are sharpest (the so-called sweet-spot) around 2 stops from their biggest aperture (mostly around the apertures of f/8 and f/11) , but the problem is that these apertures kill the available light hitting the sensor of your camera. You could turn up the ISO (to 102400 if you have a Nikon D3s), but that gives you noise, and lots of it with most consumer dSLR's.
The only proper thing to do is adjusting the shutterspeed. Leave the aperture on its sweet-spot (f/9 or f/11), and the ISO at ISO100 or ISO200 (for the lowest amount of noise). But if you do that, chances are that you need exposures much longer than the available maximum on your camera, which is 15 or 30 seconds (depending on your camera). Which leaves you with the bulb setting on your camera. But how do you calculate the time needed for an exposure?
Bulb means that the shutter stays open for as long as you press the shutter release button.
calculation, exposure, iPhone, long, photobuddy in Photography, Review, Software