I recently tested another automatic exposure camera to see how well it could perform in high speed video, in particular, the motion blur in direct sunlight.
Post on Kinovea forum.
Low Cost High Speed Video Cameras Capable of Tennis Stroke & Other Athletic Motion Analysis.
The high performance, high speed video cameras, such as the Casio EX FH100, with full manual exposure control, as discussed above, are not currently in production in 2013. They are worth it, but are now expensive and difficult to find.
How about much lower priced cameras with automatic exposure control?
General High Speed Video Cameras with Automatic Exposure Control. To video tennis strokes, low priced, high speed video (> 60 fps) cameras are available. The currently available cameras all have automatic exposure control (AEC). The shutter speed selected by the camera's automatic exposure control might not be optimized to minimize motion blur. In other words, you often get too much motion blur with automatic exposure control cameras. The amount of motion blur from these cameras is not predictable from available information but can always be measured in tests.
Canon Powershot ELPH 110 HS/ IXUS 125 Tests. I purchased a low priced Canon Powershot 110 HS / IXUS 125 camera in order to test it for tennis stroke analysis. It does 240 fps at a reduced resolution of 320 X 240.
The automatic exposure control selects the shutter speed based on the light received from the scene. The specs list the fastest shutter speed as 1/2000 sec, but it is not known if that shutter speed is reached for high speed video mode. Unfortunately, predicting the shutter speed that this camera's AEC might select is not possible without testing.
To test for shutter speed/ motion blur in direct sunlight -
1) Observed the motion blur on a rotating disc.
2) Observed the motion blur on the tennis ball and racket of a tennis serve.
I found that a very important setting for minimizing motion blur was the zoom setting on the lens. The widest angle zoom aperture setting has the fastest f#, probably 2.7. The wide angle zoom produces very small motion blur in direct sunlight - see videos below. The telephoto aperture setting is probably f# 5.9 and produces significant motion blur - see videos below. In fact, the telephoto videos below show that the motion blur from the ball streak is roughly equal to the distance that the ball travels between frames. This implies that the shutter speed for those videos was very slow, roughly equal to the time between frames, 1/240 sec. For these videos, it might also have been important for the AEC that more skylight was accepted by the wide angle field of view than by the telephoto field of view. See note below on light metering.
To attempt single frame advance on Vimeo press the play-pause control as fast as possible. The video image quality after compression on Vimeo is not as good as viewing directly on my computer or on the camera's display.
Widest angle zoom setting - small motion blur
Most telephoto zoom setting - considerable motion blur
These tests were under direct sunlight to get a fast shutter. With less light the motion blur will increase. See also other Canon high speed video tests of tennis serves and also a rotating disc test to show Jello Effect distortion and shutter speed.
This camera cost $119, refurbished, with free shipping on sale from Canon. The one I received was in like new condition.
The Canon 110 HS camera is capable of showing the fastest parts of the tennis serve with wide angle zoom setting and under favorable lighting conditions. Other Canon Powershot cameras with high speed video might work in the same way. ? Other low cost cameras with high speed video might also produce small motion blur with wide angle lens settings and in direct sunlight. ?To minimize motion blur - video in direct sunlight with the widest angle zoom setting. Also, have a bright background, include some sky (but not sun) in the field of view.
Note: The Canon Powershot 110 HS in high speed video mode uses Canon 'Evaluative' light metering to view the full scene for its automatic exposure control. Here is a general link on Canon Evaluative light metering. It is not very clear or useful and may not apply to the Powershot 110 HS / IXUS 125.
http://www.cyberscholar.com/canon/camera/index.cfm?page=trainingCenter&product=evaluative_metering&productPage=mod0101&menu=mod_on1Edited by Chas Tennis - 10/31/13 at 8:19am