Asahi Pentax Spotmatic SP500

Classic Pentax M42 & K Mount SLRs:

Asahi Pentax Spotmatic SP500

by Karen Nakamura


Overview and Personal Comments

In 1971, Asahi Optical Corporation released a series of cameras. The first was the Spotmatic SPII, its flagship model and the second was the SP500 which was designated the budget model. Using the text or images on this website without permission on an ebay auction or any other site is a violation of federal law.

Unfortunately, Asahi didn't know how to make a budget model so all they did was change the shutter speed dial to make 1/500 the top speed and not 1/1000. But all they changed was the painting/etching on the dial and not the shutter mechanism itself. So you can actually turn the dial one more click past 1/500 and get a 1/1000 sec shutter speed.

So other than from that oddness, the SP500 is identical to the SPII. Odd how marketers work, huh?


Interesting quirks

The SP500 has stop-down, match-needle exposure metering. You flip a switch on the left side of the lens mount, which 1) stops down the viewing lens to the aperture you've selected and 2) turns on the metering circuitry. There's a little needle on the right side of the viewfinder that goes from high (too much light, stop down) to low (too little light, open up). What I like about match-needle exposure metering (as opposed to match-diode) is that you can tell exactly how much light you need to add or lose. What I also like about the SP500 is that when you engage the meter, you automagically get Depth of Field (DoF) preview, something that even some expensive contemporary cameras don't have.

The fixed focal length Super-Takumars that came with the Spotmatics easily were at the top of their class when they came out and they still best all of the consumer level zoom lenses that people buy. They were multi-coated with a very hard coating process. If you see a Super-Takumar, buy it.

Although photography teachers like to recommend the Pentax K1000 and its clones for their students, I think they'd be better off recommending early screwmount Spotmatics. The lenses are excellent and in good supply, the metering is still spot on, and best of all, prices are still reasonable. The Pentax K bayonet mount is excellent, but I still have a soft spot for the screw mounts.

Availability of batteries for the Spotmatic is better than other cameras of the era because the Asahi engineers built in a bridge circuit in the metering which makes it battery voltage independent. This means you can use the original 1.35 mercury PX400 battery, or a 1.5V silver-oxide replacement without problems. An exact fit PX400S is available, or you can use a #392 cell with a small rubber-O ring (purchasable at any fine home repair center or DIY store) as a spacer. I believe a #397 also fits as well.


Technical Details

Camera Name
Pentax Spotmatic SP500
Asahi Optical
Place of Manufacture


Date of Manufacture
Focusing System

Single-lens reflex with pentaprism eye-level viewfinder

Lens use helicoid focusing

Lens Mount

Pentax/Praktica screwmount (M42)


Focal plane shutter
1 sec ~ 1/500 + 1/1000 (hidden)
X-sync = 1/60

Metering System

CdS TTL metering (stopped down only)
EV 1.7 ~ 18 (ISO 100)


Hotshoe, PC connection

Film type / speeds

135 type (35mm standard film)
ASA - 3200

Battery type

1.3v mercury PX400

(when Mark Hama repaired my camera, he replaced the battery with a silver-oxide "Exell S400PX" cell).

Dimensions and weight

Retail price


My Pentax Screw Mount Lens Collection

(17mm, 35mm, 50mm, 55mm, 135mm)
with some for sale!



About Asahi Optical Co.

You see both Asahi Pentax and Honeywell Pentax cameras on the market, what's the difference? Asahi Optical Company is the manufacturer of the cameras and has a very hallowed history. It was founded in 1919 to make optical lenses. It came out with its first SLR, the Asahiflex I in 1951. Pentax is the name of their first SLR with a pentaprism (penta-prism = pentax) which came out in 1957. Since then, it's been their tradename for their series of SLRs, just as EOS is the trade name for Canon's electronic SLRs.

Honeywell was the U.S. importer for Asahi cameras until the mid-1970s. Cameras that they imported are stamped "Honeywell Pentax" on the nameplate, not Asahi Pentax. With the minor except of one camera that was designed to accomodate a Honeywell flash unit, Honeywell Pentaxes are identical to Asahi Pentaxes.

About the only things with a stronger cult following than the Pentax screw mount cameras (Spotmatics) are their K-mount cameras, including the K1000. The K1000 which is now being made by Chinese companies and branded under Chinon and other labels, is often recommended by photography instructors. This has caused the price to stay about $200 for a new set. My own recommendation is to stay with the screw mounts. There is a wider variety of lenses and prices are relatively good. There's also a very strong cult following around their gargantuan Pentax 67 medium format SLRs.

Trivia: "Pentax" was one of the names the Nippon Optical Corporation cycled through when coming up with the name of their new camera in 1948. They ended up calling it the "Nikon" instead.


On the Net

Praktica/Pentax M42 Screwmount




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