5:1 is micro range, not macro. Sure, it *can* be done without a 'scope, but with limitations.
* A short lens on long extension gives magnification; your working distance is that focal length.
* Longer lenses allow|force you to work further away, but you need LOTS of extension for magnification.
* Reverse-stacking primes gives you a working distance of ~45.5mm with a Pentax secondary.
* 5x / 5:1 magnification with any of these methods mean losing 6 stops of light. Use flash.
* A Raynox retains automation and doesn't eat light, but you need a LONG lens for great magnification.
My recommendations:
* If you want 5x and pTTL flash, a Lil'Bigma 170-500 with a Raynox DCR-250 is for you. (I'll even sell you the zoom!)
* If you want a short rig and can use non-pTTL flash, reverse-stack a 24mm MF prime onto a 135mm (AF or MF).
* Or for a little more room, reverse that 24mm prime on 150mm of extension (macro tubes and/or bellows).
For more ideas, see
https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html