This little article is part of my photo reference set on Flickr. Clicking the photo above will take you to the photo page on Flickr, with quite a few notes about the cameras on the photo itself.
When I was looking to move from a Pentax KM to a Pentax MX, I was unable to find any good photos comparing the sizes of the two series of bodies. So, after I received my MX and before I gave my KM to a friend, I shot them side-by-side at some straightforward angles in case this information is ever valuable to anybody else.
As far as other layout differences between the K-series and the MX (other M-series have even different layouts, being Av bodies), few are notable. K-series bodies either have no indicator (K1000), or a spin wheel to describe what sort of film is in the body. I prefer either of these to the memo holder of the MX, wherein one slides part of the box the film came in. I’ve never used these memo holders, I think they’re ugly and I think they’re awkward. Depth of field preview has been merged into the self-timer lever on the MX, which is a nice UI simplification. The ISO adjustment wheel (outer ring of shutter speed dial) on K-series bodies is of the sort that one lifts and rotates to adjust. On the MX, a tiny button on the shutter speed dial must be depressed, and then the outer ring turned to adjust the ISO. Which, unfortunately, only goes to 1600. Setting it is a real pain, though, compared to the old method… and I have tiny fingers! Finally, one of the biggest differences is match diode in the MX vs. match needle in the K-series. Personally, I choose diodes… Less precise, but also less fragile. Love the finder on that camera, and the LEDs are the icing on the cake.
Check out the Pentax MX group on Flickr.