The Phochron XA shutter tester is easy to use, and has a built-in illustrated manual available on the LCD display!
It's easy to just use the included LED and single sensor for any shutter type. If you want to have more critical testing of a vertical or horizontal focal plane shutter, an additional plug-in sensor unit will be available. I didn't try it, as I just wanted the quick and easy shutter speed measurements from various cameras.
Why would you possibly want one?
That's easy for me to answer. If I sell a camera on ebay, I would like to be able to state how accurate the shutter is. Second, what about those box cameras? What's the shutter speed. Third, I am always surprised at how much off a shutter may be on old cameras. If you are wondering why negatives may not be quite what you expected with a certain camera, it could very well be that the shutter you thought was firing at 1/500 sec is actually 1/125. That's two stops off. Of course, it's a useful testing item.
If I have any suggestions, it would be that some sort of cradle with a tripod socket could be an add-on. It's useful to be able to have the Phochron XA solidly mounted for camera testing. I found the shutter tester easy to use, and a lot of fun, since I could fire a shutter repeatedly, and the display would show me all of the tests for a certain setting, as well as a summary with the average time.
Eric plans to put together a Kickstarter to fund production of the shutter tester, which is called the Phochron XA. You can see more about it at his website, phochronxa.com
Testing the shutter.