I can't believe that I am posting the very first message in the Pentax section of this forum !
I have recently bought a Pentax *1stDL2, largely because I LOVE Pentax, partly because its specifications seemed to match what I was looking for, partly because I could afford it, parly because I really liked the "feel" of this camera before I bought it (I am one of those people who would NEVER buy a new model of camera from a website, because getting a camera that "feels right" is SO IMPORTANT, and no amount of pictures and written words can ever substitute for a few minutes of "hands on"), and partly because both Pentax and my retailer advertised that it should be compatible with all my existing lenses.
SHOCK HORROR then when I was struggling to find adapters to fit to my range of lenses and accessories, and wrote to Jessops Head Office (my supplier) for advice, that they replied, saying that "they DIDN'T recommend fitting old M42 screw lenses to this camera !"
The main point of buying this camera was so that I COULD use all my existing lenses with it !
I have now discovered that there are two different designs of adapters made for mating M42 scew lenses to my new camera.
One type has a flange with a locking hole in it, that allows the old lense + adapter combination to bayonet onto the camera and engage securely with the locking / release mechanism ....... but unfortunately the flange spaces the lense away from the camera body a little and prevents many lenses from being able to focus to infinity
The other style has no flange, thus allowing the lense to mate flush with the camera mount and so allowing that infinity focus
..... but alas, this design cannot engage with the locking mechanism. Pressing the release button on the camera when you want to remove one of these lense + adapter combinations ... has no effect, and you end up unscrewing the lense out of its adapter, which you then have to fish out of the camera body
This makes quick changing lenses IMPOSSIBLE, rather defeating the whole point of a bayonet mount system, and greatly increases the risk of dirt and foreign bodies dropping into the camera body while you are trying to fish out "stranded" adapters. Inside a nice, clean, brightly lit studio this may not be such a big problem, but try doing it on a beach with sand blowing around, or at night, or outdoors in the pouring rain !
The other MONSTER problem with these adapters is that they have no electrical contacts or even aperture activation pins, so the lenses and the camera can only be operated in FULL MANUAL MODE.
Moaning aside, I do like my new camera. I love the way I don't have to switch it on and waste battery power when framing possible shots, (like I have to do with all my other digital cameras), and I like the "energy efficient" MANUAL focus and zoom facilities too.