Upload & Sell: On
I perform this operation in a straightforward and somewhat brutal fashion. Note that, on some K-mount lenses, it's possible to remove the end of the aperture lever without the snipping described below, but many have a single-piece lever that goes all of the way in, right to the diaphragm. With this arrangement, you can't simply remove the whole lever, as it disables the diaphragm. I don't bother fussing around any more. Off with his head!
First, I remove the plastic ring/sleeve that the lever shield is attached to (usually it's a single piece). The shield ring is held in place by three small screws that go into the side of the K-mount. You can see the head of one of these screws just below the leverectomized K-mount in the first photo below.
Once the shield ring is off, I cover all of the butt end of the lens with masking tape, and then cut off the aperture lever with a pair of crosscut or bullnose wire cutters. One snip - right off! The -A* 200/2.8 is deeply recessed into the lens body (about 4cm), and so you don't have to worry about getting sticky tape stuff on the glass. Many other lenses have the rear element right at the mount. In this case, I simply cover the rear element with a small disk of clean paper, and than tape it up. The lever is very hard steel, so don't loose control of what you're doing while you're cutting it off - stay in balance. It's easy to nibble off the shield using a Dremmel, but I usually take the cutters to that too - brutal! I don't attempt to Dremmel or cut off the aperture lever, as I figure the vibration imparted to the lens can't be a good thing.
I've done this to a few quite valuable Pentax lenses that I later sold, and it had no apparent effect on price. I suspect that there are more EOS DSLR shooters using manual focus Pentax K-mount lenses than Pentax DSLR shooters. I'll be snipping my first -FA* lens later today.
I have two types of K to EOS adapters (more correctly called K to EF adapter), as shown in the second photo below, which is a front/back composite of both adapters. The one on the left was the first one I found in 2004, made in Germany by Mr. Rolf. I don't know if he's still in the business. I haven't seen them on eBay for many years. The second adapter on the right in the photo below arrived on a lens that I bought about five years ago from Mark Hubsand (16-9.net). I don't know anything more about it, but it's a really good adapter. I have no experience with the K to EOS adapters currently on the market.