Digital Slow Motion
Posted 08 January 2007 - 08:24 AM
Posted 08 January 2007 - 08:59 AM
Simple question: Is it necessary to open the aperture when shooting slow motion on digital formats?
if you shoot with a video camera that is only capable of 25fps or 50i and you add the slowmotion in post, then no.
if you shoot with a video camera capable of variable frame rates like the hvx200/varicam/etc then you have to compensate for the exposure loss one way or another. you could do this opening the iris, adding more light or using digital gain.
Posted 08 January 2007 - 09:08 AM
But, in practice, I don't think it can be quite that simple. I think it also depends on how the camera generates its slow motion, which isn't always in exactly the same way as a film-based camera. The Sony HVR-V1U, for example, shoots a burst of 240 fields (not frames) per second, so I would assume (and somebody please correct me if I'm wrong here) that you wouldn't need to compensate for the reduced shutter speed by opening the aperture as much as with a film camera, on that particular camera. Ultimately, though, you're still bound to the laws of physics.
Posted 08 January 2007 - 12:51 PM
However, most people converting 60i/50i footage to slow-motion in post will at least shorten the shutter speed to reduce motion blur on each field, like to something like 1/100th of a second -- in which case you would have to account for the exposure loss from shortening the shutter speed.