Computer-based shutter speed tester
	General notes What you need The parallel port Positioning the photodiode

For all of this to work you have to have: A computer with a parallel port plug. This is true for most desktop computers and for laptops that are more than about 3 years old. In fact, the best candidate for this type of activity is a an old laptop that is no longer fashionable - you can position it where you want without having to worry about lots of cable.   But it must have a Pentium CPU chip. The software is dependent upon this. A parallel port plug and some cable. I used a leftover from an older machine. Enough soldering skill to do some pretty simple construction work. And, of course, PATIENCE. Top The Parallel Port The parallel port of a PC is based on a largish plug and a hunk of cable. All we are interested in a little bit of this - about 3 of the 25 possible bits of wire. But don’t be daunted it is not all that bad. What you have to do is to work out which connections go where. And the simple way to do this is to take the whole thing and tap off the little bit you want. Top Positioning the photodiode You need some means of positioning the photodiode behind the camera. This gets more complicated as the types of cameras grows. I have 16mm, 25mm and medium format plus a Rolleiflex and a Minoltaflex. My solution was to use a redundant slider pot from my junk box and to attach it to a Jiffy box. With the correct positioning I can go from a few mm up to 10mm from the table. But if your interests are more limited you can use a sticky tape solution and that will work Top