soundcard shutter tester works great!

[d.s.]

I made one of these many years ago from parts gotten from Radio Shack. I use cool edit program from the web, (you can expand and zoom the field to better see the actual beginning and ending of the shutter). A cheap red laser pointer, (found in walmart / K-mart around $5), is what i use as the light to shine through the lens. Its very bright and works very well w/ the radio shack photo eye spectrum.

dee

[BennehBoy]

A chap in the flickr large format group wrote some java code that will listen to the audio stream and tell you the actual shutter timing and the nearest 'normal' time.

link here