[doppler (Rick)]

Hi Aaron, old pentax pk mount lenses (on a canon 1100d) are all that I use for my wide field astro pics. I have bought a couple of these adaptors from different suppliers both of reasonable quality. There are a few issues that are easy to overcome. The first is focus, you need to use live view to focus, try focusing in the daytime with the eyepiece view finder and you will see what I mean (when you review the pic you just took). The second is CA, bright stars will become bloated and red or blue, all you need to do is stop the lens down a few stops. Because of the design of the lens diaphragm you will get star spikes on the brighter stars. You can make a lens cap to stop down the aperture to reduce the spikes. Here's a couple of pics taken with a 135mm Ricoh f2.8 lens.