The Pentax KX - When Pentax Made a Nikon

If it looks like a Pentax and sounds like a Pentax, but works like a Nikon...is it a Pentax?

  Updated Oct. 1, 2022

​    There, there, Pentax Nation. Your clickbait detectors just needed a little recalibration, that's all. As for your well-known inferiority complex, there is only so much one article can do, but I'll give it my best effort ;-). All kidding aside, we are going to take a closer look at my favorite Pentax SLR, Nikon-tainted as it may be, and how it came to be so.

  Asahi Icarus?​

    We pick up the story in 1969. Pentax (aka Ashai Optical Company) was comfortably ensconced as the 35mm SLR sales leader with 25% more SLRs produced than their nearest rival, Minolta, and a touch over 50% more than Nikon and Canon combined. In other words, they were flying high. But amid the sunshine and lollipops lurked a small but ominous warning. They were losing altitude. Sales had fallen by 16% from the previous year and would continue to spiral downward for the next half-decade. The causes: 1) reluctance to abandon the M42 screwmount that had served them so well for the past dozen years, and 2) failure to keep up with their competitors when it came to automatic full-aperture metering. Both of these factors equaled less convenience for photographers, particularly newcomers. By 1971 the sales spin had tightened to 40% of its 1967 peak and wouldn't bottom out until 1974. This coincided with a commensurate 40% jump in Nikon's fortunes in 1972 with the introduction of two new models, the Nikon F2 (late-1971) and the Nikkormat (Nikomat) EL. For the first time in history, Nikon sold as many SLRs as Pentax in a year.

  Pentax and Nikon Get It On

    While Nikon and Pentax had been competing in the 35mm market since the 1950s, it was particularly from the early-'70s onward that they really began to go at each other. This occurred during a general rise in competition between all of the Japanese manufacturers after they had collectively pushed the German 35mm SLR makers from any sort of effectiveness in the SLR market by the late-'60s. But it seemed that the struggle between Nikon and Pentax through the first half of the '70s had a bit more of an edge to it. Pentax opened the festivities by introducing the first aperture-priority, electronically-controlled SLR in the world, the Electro Spotmatic, in late-1971. While it was basically a prototype (and only available in Japan), the production version, re-labelled the ES, soon followed in 1972, beating Nikon's Nikkormat EL (the second aperture-priority, electronically-controlled SLR) to market by a whisker. The ES and EL were the only two SLRs in their category at that point, so naturally Pentax and Nikon would be keeping a close eye on one another there. Nikon now (briefly) had a four-model SLR lineup: the  Nikon F2 & F (which would finally disappear for good in 1973), and the Nikkormat EL & FTn. As noted earlier, this all coincided with Nikon's catching up to Pentax in sales, which only increased the angst at Asahi. 

    Pentax responded in June of '72 with their official introduction of their Super-Multi-Coated (subsequently abbreviated to SMC) Takumar lens lineup, becoming the first major Japanese manufacturer to do so (they had prototyped it on very-late Super Takumars in 1971). And this wasn't just your run-of-the-mill multicoating either, my friend. Up to seven layers of color-popping, flare-reducing, ghost-busting goodness. This left Nikon, the self-proclaimed "leader" of the Japanese optical industry in a quandary; they had only recently developed the capability to apply five layers of coating to a lens surface and had not even brought that to market yet, and here was sales-spiraling Pentax pipping them to the post in their area of expertise. Such insolence was not to be borne, so Nikon did the only logical thing...they denied it ;-). In the same way that Zeiss had denied that Nikon and Canon could possibly have surpassed them optically in the 1950s, now Nikon was falling into the same trap. Their calling-out of Pentax inevitably heightened the already-existing tension between the two companies. Once Pentax demonstrated that their fancy new process (bought from Optical Coatings Laboratories Inc., who had developed it for NASA spacecraft windows and then re-engineered for photographic lenses it with input from Pentax) was legit, Nikon doubled down, claiming that SMC was overkill...that they could do more with five layers than Pentax could with seven...that on simpler lens constructions you didn't even need multicoating anyways...blah, blah, blah. Without going any further down that rabbit hole, suffice it to say that there was no love lost between Pentax and Nikon at this point, with the fortunes of both companies going in opposite directions and Pentax desperate to halt their sales slide. Cue the development of the K-series of SLRs...  

  Birth of the KX
  
​    By 1973, Pentax knew that their golden goose of the M42 screwmount was cooked. They had steadily been losing market-share to their bayonet-wielding competitors for five years and they had wrung the last drop from it in the form of full- (open-) aperture metering with the introduction of the ES model and SMC Takumar lenses. The Spotmatic F was the final iteration of the line to receive this upgrade and Pentax briefly entered a collaboration with Zeiss (which, needless to say, didn't work out long-term). Both Zeiss and Leitz had bowed to the inevitable and had decide to partner with the Japanese in SLR development instead of being completely plowed under. In 1972, Leitz entered an agreement with Minolta that lasted into the '80s, while Zeiss and Pentax danced around for a bit, with Pentax eventually deciding they were better off on their own and Zeiss ending up partnering with Yashica (an alliance that lasted into the 21st century). But Pentax did not emerge from their fling with Zeiss empty-handed: they walked out with two lens designs (a 15/3.5 and a 28/2), and more importantly, what would become the K-mount. Coincidentally, the K-mount and the Contax-Yashica (C/Y) mount both debuted in 1975, sporting very similar overall dimensions. Spooky ;-). 

    The K-Series initially consisted of three models: 1) the base KM, 2) our friendly KX, and 3) the range-topping K2. Pentax also brought out a newly-christened SMC PENTAX (the classic Takumar name was dropped) lens family, some of which were merely updated SMC Takumars, while others were all-new designs. In Pentax' own words:  

The KM is essentially the Spotmatic F (the world's most popular fine camera) updated and improved with the new K bayonet mount.

    The K2 was:

...the cream of the K Series. 

    The KX slotted neatly in between the KM and K2 with a nice array of features and it drew heavily from the ES II (1973) for its layout, styling, and operation. But here is where Nikon returns to the picture. Whether to intentionally poke Nikon or because Pentax actually felt that these features were necessary to try and pull potential buyers in, the KX sported some distinctly Nikon-inspired features:

• Exhibit A: In a case of less-inspired design, for whatever reason, Pentax adopted Nikon's irritating (particularly for left-eyed shooters) meter power switch integrated into the film winding lever. Swing-out to the ON position matched the F2's 20 degrees. The Nikkormats had a 30-degree swing-out. And there is my only real gripe with this camera :-). Pentax tweaked this a bit by incorporating the partial shutter press method from the ES to fully activate the meter, which would then remain on as long as the wind lever was swung out, just like the Nikkormats and Nikon F2. This feature would be passed down to the KX' successor, the MX, before Pentax mercifully came to their senses with the LX in 1980.

Nikon F2 Power Switch/Wind Lever

Pentax KX Power Switch/Wind Lever

• Exhibit B: Now a case of copying and improving upon a Nikon design ;-). On the F2, Nikon integrated the depth-of-field (DOF) preview button with a lever-collar to activate manual mirror-lock-up (MLU). With your middle finger you would press and hold the DOF button in while pulling the lever collar to the right with your index finger to raise the mirror. To lower the mirror, you then just gave the collar lever a flick back to the left with your index or middle finger. They would retain this for the F3, as well. On the KX, Pentax copied this control layout for these two functions but reversed the maneuver (thus cleverly avoiding any Nikon patents): first, you pulled the lever-collar to the right and then pressed the DOF button in to raise the mirror. To lower the mirror, flick to the left just as on the Nikon. The advantage to Pentax' method was that you could do everything with one finger.

Nikon F2 DOF/MLU Controls

Pentax KX DOF/MLU Controls

• Exhibit C: We move to the viewfinder. With the Nikkormat EL, Nikon had come up with an elegant solution to displaying both the meter-recommended shutter speed (with a black needle) and the actual mode or shutter speed setting (with a transparent green pointer that overlapped the corresponding number on the scale on the left side of the viewfinder. Lovely, and a feature that would survive on the EL2, FE, FE2, and FM3A models. On the KX (and K2) Pentax handily lifted this little pointer, changed the color to blue and placed it on the right side of the viewfinder, where their shutter speed scale was already located from the ES and ES II models, et voila: second patent avoidance maneuver successful ;-). But again, as with the DOF/MLU thing, Pentax made an improvement: they increased the font size of the numerals in the viewfinder, making them easier to see than in the Nikkormat and later Nikons. Interestingly, by the time the FM3A came along (over 25 years later), Nikon had adopted blue for the pointer color. Hmmm?

Nikon EL2 Shutter Speed Pointer

Pentax KX Shutter Speed Pointer

• ​​Exhibit D: Now comes the big one, the one where Pentax was going all-out: Lenses. The rivalry between Pentax and Nikon became the biggest when it came to optics, as noted above. With the first series of K-mount lenses, Pentax was desperate to try and wrest back some of the market share they had frittered away to Nikon (and Canon) by hanging on to the M42 screwmount for too long. First off, in response to Nikon's pooh-poohing of SMC, Pentax started slapping the full seven-layer treatment on even their basic 55 and 50mm lenses, and went so far as to apply it in between cemented surfaces (where the gains would be minimal). That was more of a pride thing, but the second area was all about grabbing back defectors to Nikon. For well over a decade, Pentax had used 49mm as their standard filter thread size on their Takumar line of lenses, which were some of the most compact on the market. And only a year after introducing the K-mount they would return to that 49mm standard with their compact SMC-M Pentax lens line that accompanied their new super-compact MX and ME SLR bodies in 1976. Which makes the adoption of 52mm as the standard filter thread size (covering 24 - 150mm except the 135/2.5) for the first generation SMC K lenses all the more telling. Really...three measly millimeters? Not just any three measly millimeters, you see. Canon's and Minolta's then-standard filter thread size? 55mm. Olympus? Good ol' 49mm. I wonder who had 52mm standard filter threads...? Hmmm, that only leaves one member of the Big 5...nattering Nikon. And there is your final indicator of who Pentax really was fixated on when the KX (and the entire K-Series, for that matter) was conceptualized and created. So what's the big deal? What would matching Nikon's standard filter size accomplish? Well, what do photographers use filter threads for? To mount filters...which are extra accessories that they have to buy. What Pentax was trying to do with the SMC K lenses was to lure Nikon owners to the K-Series SLRs by not having to replace their existing 52mm filters and other thread-on accessories.   

50/2 Pre-AI Nikkor Reverse-Mounted w/ Nikon 52mm BR-2A Adapter

55/1.8 SMC PENTAX Reverse-Mounted w/ Nikon 52mm BR-2A Adapter

    The crazy thing was, from a marketing perspective, it worked. After seven straight years of declining sales, in 1975, Pentax moved just under 600,000 SLRs, an increase of nearly 65% over 1974. And half of those were K-Series, without which it would have been an eighth consecutive year of decline. All this while Nikon sales had plateaued temporarily at just under 400,000. Both manufacturers would see much more sales success during the final manual focus SLR boom from 1976 - 82, but it was the K-Series that got Pentax back in the game, and that was a result, at least in part, of Nikon's trash-talking lighting a fire under them ;-). Okay, okay...so the KX isn't really a Nikon, just the closest any other manufacturer came to one ;-). So what makes it my favorite Pentax? 

  KX Kudos

    Balance is the keyword for me when it comes to the KX. From its feature-set to the way it feels in the hand, it hits closest to my personal Pentax-shaped bullseye (YMMV, of course :-)). Even with all those pilfered Nikon tidbits it still handles like a classic Pentax, not too big, not too small...it's the Mama Bear of the clan (630 grams/22.2 oz). It inherited the brighter silver-coated prism, SMC eyepiece, silicon photodiode (SPD) centerweighted meter of the K2, and it even outdoes its higher-end sibling when it comes to displaying the aperture readout in the viewfinder (you would have to upgrade to the newer, more-expensive K2DMD to equal that). No jamming your eye socket into the eyepiece in a vain attempt to try and see the entire field of view (Looking at you MX ;-)). The shutter release lock allows for (T)ime exposures when used in concert with the (B)ulb shutter setting. The ISO range of 8 - 6400 is more than enough for any modern film shooter. Batteries for the meter are the still-current SR44/357/S76, so no conversion hassles there. With its beveled bottom plate and other subtle ergonomic adjustments to the already-excellent Spotmatic paradigm, Pentax' long-time slogan of "just hold a Pentax" definitely fits the KX, for me anyways :-). Slap an SMC Pentax 55/1.8 (an under-the-radar gem of a lens, with stellar optical and build quality) on the front and you have one of the sweetest, simplest, yet still very capable mechanical 35mm packages ever, full stop. Oh, and just one more thing: slip the K-to-M42 adapter into the gaping maw of the KX and you can use any Pentax M42 screwmount lens (and almost any other brand, for that matter; just check carefully first before getting all ham-handed ;-)) with stop-down metering and perfect infinity focusing making for even more versatility. Conversely, you can mount any newer Pentax lens, as long as it has an aperture ring, and get full-aperture metering. 

    The balance of the KX is also typified in comparison with its competitors from 1975:

• Canon FTbN - the Canon is almost 20% heavier; doesn't display the aperture value in the viewfinder, uses the obsolete 625 mercury cell (requiring a diode conversion to use a modern 357 silver-oxide cell) to power its less-sensitive (2.5 - 18 EV) CdS meter; a much smaller ISO range of 25 - 2000; it does have DOF preview & MLU; a dimmer viewfinder with 0.85x magnification @ 88% coverage vs. 0.88x/93% w/ 50mm lens
• Minolta SRT-202/SR-505 - 10% heavier; does have a full-info viewfinder but it is busier and less-intuitive than that of the KX; same type of meter (CdS 3 - 17 EV) and battery (625) limitations as the FTbN; ISO range very slightly larger (by 2 whole ISO) than the KX of 6 - 6400; has DOF preview, but MLU was deleted from SR-Ts from 1973-74 onward; multiple exposure capability that the KX lacks; slightly dimmer viewfinder @ 0.86x/94% 
• Nikkormat/Nikomat FT2 - nearly 25% heavier; no aperture display in viewfinder; same meter (CdS 3 - 17 EV) and battery (625) limitations of the SRT-202 & FTbN; smaller ISO range of 25 - 1600; does have DOF preview & MLU; dimmer viewfinder @ 0.9x/92%; has a louder vertical-travel shutter with 1/125 sec. flash sync. vs. the typical 1/60 sec. horizontal-travel KX flash sync.
• Olympus OM-1 - the newest design (1972; the others all originally dated from the mid-'60s with minor improvements and some deletions) and most formidable challenger to the KX; almost 25% lighter than the KX; doesn't display shutter speed or aperture value in viewfinder; same meter (CdS 2 - 17 EV) and battery (625) limitations as the Canon, Minolta, and Nikkormat; smaller ISO range of 25 - 1600; has DOF preview included on every lens and MLU (the only Olympus OM to ever have it); superior viewfinder specs of 0.92x/97% coverage with a small penalty in eye relief (Pentax would directly target the OM-1 viewfinder with the MX viewfinder @ 0.97x/95% with more of an eye-relief penalty ;-)); 14 user-interchangeable focusing screens (none of the others in this category had that feature)

​
  These are all excellent mechanical SLRs that I enjoy using, and the point of this comparison is not to slight any of them, but rather to illustrate the overall competence of the KX. No, it is not the "perfect" SLR (a mythical creature if ever there was one :-)). Like every other match-needle SLR, the KX is limited by the amount of light that the viewfinder admits to illuminate the display, making it difficult to use in low-light situations. There is the poky advance lever for left-eyed shooters. Yes, the 1/60 flash-sync. speed is slow. But...it...does...not...matter. Pictures are taken with cameras, not spec sheets. And the KX is simply flat-out fun to use and feels great in the hand and to the eye. Original SMC PENTAX glass takes a back seat to none of its contemporaries and the focusing feel (good ol' aluminum-on-brass) will make a Nikkor whimper ;-).

    With the inflated prices of K1000s nowadays, you can score yourself a KX for the same or less money with a bit of patience. Sure, they are less common than K1000s (by about 10 to 1 ;-)), but that relative obscurity has also helped to keep values down. The KX was available new for only two years, with about 200,000 produced, so they are below many people's radar and have basically zero Interweb notoriety compared to the K1000 (not a bad camera at all, but currently overrated for what it is) and MX (too cramped for my hands and eye socket, and lacks MLU, but you might love it ;-)) as far as mechanical K-mount Pentaxes are concerned. The fiddly ISO control of the K2 and its more common electrical issues also swing my vote towards the KX. Problems with the meter are probably the biggest potential issue with the KX, but they seem no more prevalent than with any of its contemporary competitors in my limited experience.

    To sum up, the KX is not actually a Nikon, nor does it need to be. There are plenty of old Nikons to choose from should you prefer. And there are other Pentaxes that may suit your fancy more. But for me, the KX symbolizes Pentax at its best, with some fire in its belly and not taking any guff from Nikon...and I like it like that :-).

  References:

     Flare control in multi-coated lenses of the Seventies - Dario Bonazza
     The Honeywell Hotline Newsletter Sept./Oct. 1975 @ www.pacificrimcamera.com
     Nikkor Lenses @ www.pacificrimcamera.com
     Pentax KX Brochure @  http://www.pentax-manuals.com/literature/literature.htm
​     Various SLR Manuals @ www.butkus.org/chinon/
     Knippsen SLR Production Numbers Asahi Pentax @ http://knippsen.blogspot.com
     Knippsen SLR Production Numbers Nikon @ http://knippsen.blogspot.com