Rodolfo Paiz
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 p.1 #24 · Nikon D3s @ ISO 51,200: additional sample | |
corndog wrote:
Not to be contrary, but there's no way 1/5000 was required for this. Have a look at this shot:
http://www.robgalbraith.com/bins/multi_page.asp?cid=7-8740-9068-10086
These guys are absolutely stopped in their tracks while running and falling at 1/2000 [...] I'm with Francois, this could have been done at 1/500.
After seeing Rob's shot, I disagree. Do the math...
Rob's shot is sharp enough for nearly any intended usage. But it's definitely (even at the larger web size posted) not as perfectly sharp as it would have been if the subjects were standing still, so there is some motion blur; and the math says the same thing my eyes tell me. A flat-out run in football probably means 5 meters per second or more, but those 5 m/sec mean 2.5mm of motion in 1/2000 sec. Not enough to "matter", and I'm certainly not nitpicking... but it's not "absolutely stopped", it's stopped enough to get the desired results.
Circus performers are often diving from high altitudes or flying through the air in trapeze acts. I estimate that some of those free-falls have "hang times" of more than 2 seconds, but let's look at just 1 second for this example. After one second, gravity will have accelerated the diver or trapeze artist to 9.8 m/s. And since they always have some forward motion, a nice round number of 10 m/s is conservative. To get the same sharpness that Rob got (2.5 mm of motion) with the subject moving at twice the speed, you would obviously need 1/4000.
Once you combine the forward motion of trapeze artists with free-fall hang times that may approach 2 seconds, it's entirely realistic to have motion vectors well in excess of 20 m/s. I see absolutely no reason to question the need for 1/5000 shutter speeds in some circus settings. Obviously not all shots will require that kind of speed... but I do think that some will.
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