Originally posted by Alex645 Pentax, Nikon, and Canon have more similarities than differences; but I'll try to summarize the main differences:
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a) Legacy: You can't autofocus with a manual focus Pentax lens made in the 1960's, but you can still mount it on a brand new Pentax DSLR and shoot with it. ...
Great summary post. I'll challenge this one statement ever so gently because it's not wrong, but Catch-In-Focus is a exclusive Pentax feature that effectively makes your legacy manual focus lenses function as auto-focus lenses. You're still turning the focus ring, but you are taking advantage of the auto-focus mechanism in your camera and relying on it to fire when it finds focus. This has enabled me to get some great sports photos with really good, really cheap legacy telephoto lenses and some good band photos in low light with fast legacy primes that I either already owned or picked up for pennies on the dollar.
Pentax, more than any other brand has dominated retro compatibility.
1) Catch in Focus
2) In camera image stabilization rather than an option on modern lenses
3) Continuation of the K-Mount vs I've lost count of how many Nikon and Canon lens mount changes. (sorry you need an adaptor to you use your dad's Canon primes on a modern Canon SLR
4) Continued investment in optical view finders.
I also find that if you liked pro-level SLRs, Pentax feels more like them than equivalent alternatives from other brands. The build and ergonomics make more sense to me than going through complicated menu systems to set my exposure. Mid-level Canons and Sonys feel more like a smartphone design to me than a quality SLR.
Certainly, all manufacturers make great cameras on a certain level. Backward compatibility is a huge reason that I love Pentax.