Dear Pentax and Nikon,
I applaud both of you for sticking with the lens mount system that has been carried through the transitions from manual focusing, to auto focusing; and from film to digital. Allowing photographers to mix older lenses with new ones in their optical libraries gives both of your systems an unparalleled advantage when it comes to the palette of lenses afforded to a shooter.
On the other hand, I am constantly fighting the urge to spit in your face the way you have spit in the face of every customer using a manual focus lens with an APS-C or full-frame digital SLR by not providing them with the option to use a split-image rangefinder or microprism focusing screen. Do you know how hard it is to accurately focus a Nikkor 50/1.2 AIs lens with a D300s? One has to have to bracket focus while squinting through the low magnification finder! And that focus confirmation dot is useless for any precision. Sure Katz Eye and some Asian junk peddlers offer some “void-‘yer-warranty” screens, but it is not the same. What is more aggravating is that it isn’t like Pentax or Nikon have never designed or don’t have the ability to manufacture these types of focusing screens. They have previously been present in their wares for decades.
Some of the current SLRs have interchangeable screens – as long as you like grid lines in addition to the standard matte. It is like offering unsweetened vanilla ice cream in addition to basic ice milk – there is a whole world of flavor out there Nikon and Pentax are missing out on. Many older lenses were better built and are better optical performers than their current counterparts. The Nikon 28mm/2.8 is a prime example of that, where the durable AIs version has eight elements in opposition to the plasticy D-type with six. What is the point of getting excited about the latest and greatest digital camera released if you can’t use it to its fullest extent?
Take a lesson from Leica – notice they didn’t replace the rangefinder of the M9 with a digital focus scale. They could have, but clearly they respected their core user group unlike you headache-inducing bastards.