In-front-of-the-lens shutterrer

There are a few advantages to having a guillotine shutter in front of the lens:  1.  It’s less likely to get caught, particularly if you’re using extreme lens movements.  2.  The shutter guide helps to hold the lens in place if you don’t have a proper mounting ring.  3.  It’s a bit easier to set and release.  The big disadvantage is that it hides the lens, and if it’s a pretty brass one which you want to show off it’s nice to have the shutter behind it.  Either way, it’s a simple solution to the problem of shutters for old lenses.  Pete has yet to come across a barrel lens to which he can’t fit a guillotine shutter.