Pentax Spotmatics, any fans out there?

Uncle Bill · May 29, 2005

There was a camera show here in Toronto today I could not attend due to work, my brother scored on behalf a Pentax Spotmatic with a 55/1.8 and a 28mm wideangle for a steal. Now which battery should I get for the meter and where can I get a good source for lenses as I want a telephoto/portrait lens. I can thank my brother for this as he is a fan of his spotmatic and I hear the lens system is really good.

Bill

geraldatwork · May 29, 2005

They are excellent cameras. During the late 60's and 70's they competed with different models from Nikon, Canon and Minolta. Probably the easiest place would be ebay.

gma · May 29, 2005

Congratulations. The Pentax/Praktica/Edixa 42mm screw "universal" mount was used by many camera manufacturers in the 1960's and 70's. There are a tremendous number of Asahi Pentax, Zeiss,Yashica, Mamiya and even more aftermarket lenses available at very low cost these days. Most consider the screwmount camera a cumbersome antique. If you have an early Spotmatic with stop down through the lens metering you can use automatic, preset or even manual lenses and still have the benefit of the through the lens meter. If you have the later Spotmatic F or the ES probably you will want to buy newer Pentax lenses with the extra lever that can be metered at full aparture. Batteries of the correct voltage can be purchased from Freestyle and other mail order sources. The original mercury batteries are no longer available. Do not try to use alkaline or hearing aid batteries. If you have an accurate hand held meter, by all means check the Pentax meter for accuracy before you shoot some important subjects. Old meters often are not accurate through the whole range. Pentax cameras were precision made and last a long time. A real bargain used 35mm SLR. You might want to pick up a spare body on the web for $30-50. Even if the meter does not work you can still use the camera to make quality photographs.

I have a Spotmatic SP500, three Prakticas and a Vivitar 220SL all of which are 42mm screwmount and all sorts of lenses.

fparnold · May 29, 2005

Not to flog the standard source, but KEH has a nice selection of real pentax screwmount lenses right now. The bargain choice would be the super-takumar 105 2.8, though the 85 1.8 is also there, or the 100 f4 macro. They'd be my first choice.

I've shot quite a bit with my scavenged and refurbished ones in the last year, and they're nice camera. Probably going to list them here shortly though, as I prefer my old Nikon F for most purposes. Nothing wrong with them, but I have too many blooming cameras around here.

Nick Zentena · May 30, 2005

Spoties aren't battery snobs. You can stick any silver oxide battery that fits the battery. Other then shorter life I'm not sure why you couldn't fit an alkaline battery. The meter is designed well enough to handle non-standard batteries.

Off the top of my head I don't remember the battery that fits perfectly. I want to say a 387 or 400 watch battery. When I was looking I had no lucky finding either in Toronto. The battery shop that Radio Shack runs had a smaller battery in a little rubber ring. Kind of expensive for just a little rubber washer.

The real bargain lenses tend to be the 135mm. Basically ignored by many but very common. Pentax made good ones. So did Mamiya. I've got a real nice Mamiya 135mm. You can also get various Soviet M42 lenses.

Dan Fromm · May 30, 2005

Uncle Bill, I'm a Spotmatic anti-fan. This for two reasons.

When I went shopping for my first SLR, I found stop-down metering an, um, impediment to progress. I fully appreciate that it can be lived with.

I spent 1970 in the US Army in Germany. Most of my fellow soldiers took their snapshots with Spotmatics, which were then the least expensive nice camera in the PX. I don't know whether it was due to the users or the cameras, but enough of the Spotmatics I was acquainted with to notice had shutter failures.

I didn't get a Spotmatic, instead bought a Nikkormat at the 4 Wing RCAF's spring photo fair, still think its the better choice. Heavier, though. Having the shutter speed control concentric with the lens mount still seems more natural than putting it on the top plate.

And your brother's right, there's a lot of very good used glass around for M42x1 SLRs that's now quite inexpensive.

Cheers,

Dan

cao · May 30, 2005

Dan Fromm said:
When I went shopping for my first SLR, I found stop-down metering an, um, impediment to progress. I fully appreciate that it can be lived with.

I spent 1970 in the US Army in Germany. Most of my fellow soldiers took their snapshots with Spotmatics, which were then the least expensive nice camera in the PX. I don't know whether it was due to the users or the cameras, but enough of the Spotmatics I was acquainted with to notice had shutter failures.

The Spot Fs can do open aperture metering with the SMC Tak lenses. Also, they can work with an Alk 625 cell since the meter is a bridge circuit. I am unsure the earlier Spotties
use that circuit. Nevertheless, I tend to use a Gossen or Minolta handheld meter most of the time.

I'm a comparative newcomer to photo, but I've run more than a bit of film through my Spotties for class work, school paper, and personal pics, and think the shutter failures were a matter of abuse. Were the cameras kicking about in a ditty bag?

For the counter, I've had the loan of an F3hp for a while from a friend who is unsure about shooting film again, and I'm just finding it a heavy awkward lump in my hands. This might have to do with only having my adaptall zooms and his 55/3.5 which don't suit my style that well, but the F3 didn't make my heart sing though I recognize it as a great camera, and I'll always be slightly envious of the butter smooth wind-on. The next few days, I'll be going through the same routine with an A-1 I've been given; I'm unsure the results will differ. I may just have a Spotmatic/RB67 shaped brain.

Uncle Bill · May 30, 2005

I also have a Nikkormat Ftn which is a tank. I am just getting a spotmatic as an inexpensive system when I don't want to shoot with my Nikon F/Nikkormat or the AE1 or definatly my M3.

Bill

Uncle Bill · May 30, 2005

Next Question I have a Hannimex 105/2.8

with a universal screwmount, would that fit a spotmatic or more importantly will it work with a spotmatic? Currently its on an Fmount adapter for my nikons.

Bill

Lee Shively · May 30, 2005

I've never owned a Pentax Spotmatic but the first "serious" camera I ever used was one. I got the photo bug due to those cameras. I really should buy one since they are available so cheap these days. They had some great lenses.

The "universal" 42mm screw mount fits the Pentax directly. It was also known as the "Pentax/Praktica" mount. It was replaced by the "K-mount" which became something of a "universal" bayonet mount in it's day.

There were other screw mounts. The 39mm "Leica thread" mount was used in rangefinders. The "T-mount" was a screw mount that took adapters to use on various SLRs. There were probably some others I'm not aware of.

John Koehrer · May 30, 2005

The battery for the original SP/500/1000 was the RM400 a 1.35V mercury cell. Current mfrs. produce 1.5V cells.
Considering age of the camera & availability of the batt. I think you would be better off with a small hand held meter.

Dan Fromm · May 30, 2005

Shaggy, one of the nice things about Spotmatics is that the meter uses a bridge circuit. Voltage doesn't matter very much. That's a weak point of most of the Spotmatics contemporaries, which relied on the battery giving the right voltage.

Dan Fromm · May 30, 2005

Ah, Cao, in 1970 the Spotmatic F didn't exist.

In its day, the Spotmatic was among the smallest and lightest of full frame 35 mm SLRs, both good attributes to have.

About having a "Spotmatic/RB67 shaped brain," well, our preferences do tend to conform to the tools we use. That's why its hard to get good advice on "the next camera for ME;" everyone recommends what he uses and knows best without regard for the quirks etc. of the person asking for advice.

Bounce around in ditty bags? Not likely, I was at Materiel Command HQ. Everyone there and their cameras were pretty pampered.

Cheers,

Dan

Donald Qualls · May 30, 2005

I have a 1967 Spottie. In the almost 25 years I've had it, it's never been serviced, though it has, in the last few weeks, come down with what appears to be a bad metering cell (a CdS cell close to 40 years old failed -- must be a bad design, right?). The shutter, mirror, etc. still work perfectly, though my two Ricoh Singlex II bodies (almost ten years newer, with metal shutters) are both in a failed state with different failures. I've never found stop-down metering a big deal -- never used a camera with TTL that didn't require stop-down, so know no other way (and honestly, I don't even meter all the time, I often just set the exposure by Sunny 16 so I don't have to mess with metering). About the only thing I wish for on my Spottie is a hot shoe.

Paul Howell · May 31, 2005

You can buy an adaptor for the Spotmatic that will convert a current battery to the same voltage as the mercury 625. Although most 42mm lens are interchangable you do need to be careful. Late model Fuji Yashica's 42mms (designed for AX body) do not mount well and will not couple with standard 42mm bodies. On the rear of the standard 42mm lens is a pin that controls the aperture to close it down when metering or firing the shutter. When looking for bellows or extension tubes look for the pin. The Spotmatic F meters at full aperture, as does the ES. Fs and ES that have motor drive written on the base plate will take a motor drive. GAF (Chinon) made a body with shutter priority exposure like the ES, and Chinon also made a body with a motor winder (very slow 1.5 to 2 FPS) but sounds like a sewing machine. Cosinga (sp?) makes a current 42mm body. You can also get a 42mm to K mount adaptor and shoot with most K mount bodies with most lens in stop down metering. I have a ME with an adaptor, also a Nikon 42mm adaptor, but my 28 and 24 mm don't seem to meter with the ME and 300mm and longer cut off the corners on the Nikon. Most electronic bodies from the 70s (including the ES) are failing and unless you have a body to cannibalize will be difficult to repair.

All said I have gone though many Nikons, (F, F2, F3 FE and FG) but the Spotmatics keep on trucken along. Great basic body with excellent glass.

Donald Qualls · Jun 1, 2005

That adapter is redundant on a Spottie, though. They have a bridge type meter -- that is, the meter needle is measuring the *difference* in current through the metering cells and the speed dial potentiometer; higher or lower supply voltage will result in more or less needle displacement with incorrect exposure, but the center null will be correct (at least if you don't have a completely dead battery or so much voltage you fry something from the excess current).

I've used my Spottie with silver oxide cells, with about 25% higher voltage than the original mercury cells, for a couple years at least, and the exposures are fine.

cao · Jun 2, 2005

Donald Qualls said:
That adapter is redundant on a Spottie, though.

I'm not absolutely sure, but I think that may apply to only the Spot-F which uses a nulling bridge. The Spot II requires 3ua through the galvanometer to center it. I think the other non-F Spotties are the same. Won't the meter current for given potentiometer and photocell values increase with the battery voltage?

dr bob · Jun 2, 2005

cao said:
I'm not absolutely sure, but I think that may apply to only the Spot-F which uses a nulling bridge. The Spot II requires 3ua through the galvanometer to center it. I think the other non-F Spotties are the same. Won't the meter current for given potentiometer and photocell values increase with the battery voltage?

You are correct that bridge circuites require a minimum current for operation. However at null that current flows equally through both legs of the bridge. So unless there is insufficient voltage to pass the minimum current most any power source, in keeping with the basic component, design can be used. That is, too much voltage will certainly burn out something and too little will cause drifting. But in the case of light meters, a couple of tenths of a volt shouldn't matter.

I've used several cells in my Spot and also a Vivitar strap-on (a very miniature meter indeed!), and checked the accuracy with my Minolta Spot meter. No problem.

cao · Jun 2, 2005

dr bob said:
You are correct that bridge circuites require a minimum current for operation. However at null that current flows equally through both legs of the bridge.

I am having trouble convincing myself. I think there will be 15% greater current through the meter with the Ag cells. So the meter should read slightly higher. Maybe setting the meter's hairspring tension to center at 3.4ua would work. In short, why is the meter current not linearly dependent on the supply voltage?

modafoto · Jun 2, 2005

I started out in the SLR world with the camera that took the first pictures of me when I was born - My father's nice Spotmatic with 50 mm and 135 mm lenses.

GREAT CAMERA!

titrisol · Jun 2, 2005

The meter system does not rely on the voltage of the battery by itself, but compares voltages between two parts of a circuit. The first part has a set resistance and the second part has the CdS cell (photo-resistor). Once this has been calibrated for the resitnace of the CdS cell, the input volatge is not so important (within certain limits).
The Spotmatics (and the K1000) used a 0-meter or a needle that goes to the 0 position when balanced.

I have used silver batteries in the spotmatic for ages, in fact my dad did so in the mid 80s when mercury batteries became expensive. The only think I've found is that fresh Silver oxide batteries tend to make the needle overreact to changes, after a month or so the movement is a lot smoother and works like that for years. (a 395 cell should last 2+ years)

After all this hoollaballo of replacing with zinc-air batteries started about a couple of years ago, I bit the hook and spent a lot of money on those batteries... they last a month or two. So I checked with a Minolta SpotMeter and a 395 battery... it was within 1/3 stop for bright sky, neutral wall and shady spots so I decided to save me some money and let the camera run as it should.

I'd reccomend joining the Spotmatic list (http://groups.yahoo.com/group/Spotmatic/), where there are documents on replacing batteries as well. Diagrams of the metering circuits can be found there as well

cao said:
I am having trouble convincing myself. I think there will be 15% greater current through the meter with the Ag cells. So the meter should read slightly higher. Maybe setting the meter's hairspring tension to center at 3.4ua would work. In short, why is the meter current not linearly dependent on the supply voltage?

cao · Jun 2, 2005

If you read the Asahi or Nat Cam service manuals, you'll see that in some cases the Spotmatics didn't use a balanced bridge, and there was a specific non-zero meter curent for a centered needle. Would someone please show me the network analysis proving the current doesn't change at all? While everyone may be right in practice (the change is small), I want to be convinced of the theoretic soundness (the change is zero). Every fiber of my being says current flow is linearly dependent on voltage in a resistor net. Prove me wrong please!

titrisol · Jun 2, 2005

I don't have an answer to our question then,.... all i can say is that it worked or me :-|

Paul Howell · Jun 2, 2005

I have 2 bodies, one works fine with standard battery, the other was 2 stops high and the needle seem to bounce around a lot. Hearing aid batteries worked, but I bought an adapter for that body and all of the ills seem to resovle, it may that over the years the metering system evolved.

Donald Qualls · Jun 2, 2005

Or it may be that the one with the bouncy needle had a problem in the speed dial resistor or one of the meter cells. The CdS cells in the meter, as semiconductor devices, could potentially fail in a manner that would make their conductance voltage dependent, like a zener diode (though more commonly they fail as simple open circuit or high conductance, insensitive to light). A noisy (i.e. dirty) resistance strip or wiper in the speed dial could do the same thing, with increasing voltage amplifying an effect that's still there, but less noticeable, at lower voltages.

Pentax Spotmatics, any fans out there?

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