No, the size of the magnets are different!
Attached are two photos I took quickly of the different solenoids:
Photo 1 shows the two white solenoids: Left solenoid of Pentax K10D/Kx etc
Right solenoid of Pentax MZ7: stronger holding force! Too strong.
Photo2 shows the those two white and on the very left the green solenoid of a Pentax K30:
The gap and housing for the magnet of the green and white solenoid have a different form!!!
One can not really distinguish the magnets of the both white solenoids and I cannot measure the magnetic force, the student who did the previous measurements is now in midst of his master studies and has no time left for such experiments.
I also don't need more measurements, I have enough precise sensitivity that I can tell the difference with ease just using my fingers.
As might notice: the left (correct) solenoid is damaged, the pin to which one end of the coil is soldered onto is broken, sadly the copper wire of this winding cannot be attached anymore. So this is a defunct solenoid I kept just for reference of the holding force.
Last edited by photogem; 03-08-2018 at 07:54 AM.