View Single Post
Old 12-29-2012, 07:18 AM   #32
Chas Tennis
Hall Of Fame
 
Join Date: Feb 2011
Location: Baltimore, MD
Posts: 2,581
Default FC150 video & shutter speed estimate

Quote:
Originally Posted by Greg G View Post
I found this on YT. Looks pretty decent, considering it was shot at night.

http://www.youtube.com/watch?v=UFwc_8rTcxA
That quality HS video would be very useful for tennis strokes. You can see the body parts well. You would not see the racket face or ball position well or the fastest body motions in the serve. In bright direct sunlight the FC150 would probably? choose a shutter speed that is faster. But exactly how AUTO exposure controls would work is never made clear.

To estimate the shutter speed in the video-

If you look at second 20 just after the ball has left the racket you can see the motion blur on the racket head and ball. (I can do stop action while viewing Youtube on my laptop by pressing the mouse pad key as fast as possible on the YT 'play-pause' button.) The motion blur on the ball seems to be roughly 12".

Motion blur for objects traveling across the frame-
Motion Blur = Velocity X Exposure Time (or "shutter speed")

Say the ball is going 60 MPH
12" = 60 MPH X T

T = 12" / 60 MPH

Convert 60 MPH to inches per second
http://www.kylesconverter.com/speed-...hes-per-second

= 1056"/second

T = 12"/1056"/second

T = 0.011 second

Probably 1/100 sec - a very slow shutter.

AUTO shutter speeds for direct sunlight should produce less motion blur. Can you find a golf or tennis video where the shadows are high contrast & sharp? There are many more golf videos.

If the camera has AUTO with shutter priority or a "sports mode" I believe, but am not sure, that it will select faster shutter speeds. ??

Another camera discussion
Looking for Help Choosing a Camera
http://tt.tennis-warehouse.com/showthread.php?t=405536

Last edited by Chas Tennis : 12-29-2012 at 07:39 AM.
Chas Tennis is offline   Reply With Quote