other Pentax cameras in my collection:
Asahi Pentax (Spotmatic) SP500 [1971 - 1974]
In 1971, a number of minor internal improvements where implemented, leading to the new Spotmatic SP II model. The SP II was aesthetically different to the SP, since the more pointy apex of the pentaprism housing was slightly flattened to accommodate a fixed hot shoe. Pentax tended to allow older models to remain in production alongside their newer replacements, so the SP and SP II were sold in parallel for about 2 years.
At the same time, the old Spotmatic SP was rejuvenated as a budget model, becoming the almost identical SP500. The at-a-glance difference between the two models is that the SP500 lacks a self-timer. The SP500 was no lesser quality than the SP; Pentax simply removed a moderately ephemeral component in order to achieve a modest cost reduction, and twinned the new model with a slower lens. The name
Spotmatic did not appear on the camera nor in its instruction manual, but the SP500 was referred to as the Spotmatic 500 in advertising literature.
In brief, the SP500 was a slightly centre-weighted, full scene averaging, TTL, stop-down metering, 35mm SLR, with a viewfinder centre-the-needle exposure setting control. Not all possible shutter speed and aperture size combinations are always within the meter's measurable range, and the shutter speed dial's indexing mark changes from black to red as a warning of this limitation. For example, with the standard f/2 to f/16 lens fitted and 800 ASA film loaded, shutter speeds below 1/8th will be outside of the meter's measuring range, and with a 20 ASA film loaded, shutter speeds above 1/125th will similarly be outside of the meter's measuring range. Meter range limitations were not uncommon at the time, and can be found on other cameras such as the Miranda Auto Sensorex EE.
According to a 1971/2 photographic equipment catalogue published by Hastings based retailers Gifford Boyd, the SP500 sold with an f/2 55mm Super Takumar lens for £119.86. The original Spotmatic cost £149.94 with an f/1.8 55mm lens, or £178.04 with an f/1.4 50mm lens (the cost of the lenses sold separately were: f/2 = £43.03, f/1.8 = £49.01, and f/1.4 = £75.00). This suggests that the new SP500 body was priced at roughly £25 (or 25%) less than the old Spotmatic, which - given that it merely lacked a self-timer - made the SP500 an attractive option.
While the SP500 shutter speed dial shows a max speed of 1/500th (hence the model name), it can actually shoot at 1/1000th if the dial is turned to an unmarked stop after
500. Pentax did the same thing in 1962, when they left the 1000 stop unmarked for the S1a - a budget version of the Pentax S3.
The SP500 was sold until 1974, but replaced in 1973 by the SP1000, which was in turn identical, but for the
secret 1/1000th sec., shutter speed stop being engraved on the selector dial scale. The SP1000 was discontinued in 1976, but it's specification lived-on as the K1000.
Some Internet resources state that the SP1000 was made from 1970 until 1974, but magazine reviews and retailer advertising supports the dates I have quoted. Additionally, some Internet resources claim that the SP1000 was a low specification version of the SP II: it wasn't ... it was a derivative of the original Spotmatic.
Lens mount: M42 screw.
Focus: Fresnel lens and micro-prism centre. 0.88x magnification with 50mm lens. DOF preview.
Shutter: Horizontal rubberised silk focal plane with speeds of 1 sec - 1/1000th + B.
Meter: Stop-down aperture, Cds meter, TTL centre-weighted, average brightness, needle visible in viewfinder. DOF preview button switches the meter on/off, plus there is an automatic switch-off when the shutter is fired.
Film Speed: 20 to 1600 ASA.
Flash: Standard FP and X synch at 1/60th.
Film Advance: Ratchet type rapid wind lever. 10° pre-advance and 160° advance angle.
Frame Counter: Automatic count-up and reset.
Rewind: Via crank and bottom release button.
Size: 143 x 92 x 49mm (W x H x D).
Battery: 1.35V mercury PX-400. However, the Pentax Spotmatic has a bridge circuit, which means that you can put in a modern 1.5 volt battery and the metering circuit will ignore the voltage and still operate normally. Silver Oxide batteries are better because the discharge curve is much more even. The compatible modern equivalent is the 1.55v S400PX.
I got my SP500 in August 2018 for £7.16. It's in good condition and FWO, except for the mirror sticking up at slow speeds (the mechanism just needs a little lubrication), perished light seals, and doubts as to whether the meter works (I don't currently have a suitably sized battery for testing).
I sense that the SP500 might be the least well regarded of the Spotmatic types (save for the meter-less SL, which is redeemed by relative scarcity), hence the low price paid, but it's really little different to an SP1000, the original SP, or indeed a K1000. Despite the lower specification stop down metering, in some ways I prefer it to my Spotmatic F. I like that the meter has a on/off switch. I'm not bothered about the lack of a self-timer or hot shoe, as these are occasional use features. I also like the styling with its more elegantly pointed and tapered prism housing, making the SP500 evocative of the iconic original Spotmatic.
It didn't take me long to find a lens for this camera: a Super Tukumar 55mm f/2, which came with an Asahi Pentax S1a attached.