A great intro for this is in the blog:
I wasn't planning on initiating this assignment so I had to dig through my photos. Not the best, but anyone that has seen fencing knows just how fast the action is so my 50mm f1.8 works nicely for this with the fast shutter speed and large opening to let a lot of light in quickly.
As always EXIF data needs to be intact if you wish to participate in the mini contest!
The image you submit should be taken between the 30th April and the 13th of May 2008 (before the end of the mini-contest).
Your post must include "Assignment: Wide Open" to show your permission to count it for the contest.
*** From SuperMod Wulf: "The challenge is to open the aperture as wide as it will go. To maximise the challenge, use your fastest available lens (although, as you can see from my entry, this isn't essential - my 50mm f/1.8 was the only lens I didn't take on my recent holiday). When the moderators do the judging at the end of the week, we will go through our shortlists and disqualify any shots where the aperture doesn't match the wide open setting for the lens used (therefore, it is useful to mention both those bits of information on your entry - eg. "taken at at f/2.5 with my Vivitar 90mm f/2.5 lens").
If you haven't got a camera that allows you to demand a particular aperture then either give yourself a week off (how about picking a section of the site you haven't contributed to, like "Before and After", and seeing what you can come up with for that instead) or do some experiments to see what conditions and settings force your camera to take a wide-open shot.
Wulf" -- Hope that helps clarify things.
Again, remember, only one image per user can qualify for the mini-contest, if more than one is listed for the assignment (with assignment: wide open) all of that user's images will be disqualified.
Next week's assignment is Low Light/Night photography