Anybody Play with Pentax Spotmatics?

Discussion in 'Camera Building, Repairs & Modification' started by Uncle Bill, May 29, 2005.

  1. Uncle Bill

    Uncle Bill Subscriber

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    My brother picked up a Pentax Spotmatic and two lenses for me today at a camera show I could not attend myself. First question is which battery should I get to run the meter and two I want to hear from Pentax Spotmatic fans to on where to find a good source for lenses out there preferably in Canada . My brother turned me onto this camera because he owns one as well and loves the lens system.

    Bill
     
  2. gma

    gma Member

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    You can get a zinc/air battery of the correct voltage to replace the unavailable mercury cell that was used originally. Freestyle and other mailorder firms sell the batteries. Spotmatics used different batteries in different models over the years. You can determine which you need with a little research on the web. Alkaline batteries are short lived and become inaccurate as they run down.
     
  3. Donald Qualls

    Donald Qualls Member

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    Actually, all Spotmatic models had one sort or another of bridge metering circuit, and are semi-independent of battery voltage. What you'll see is that as the battery voltage drops, meter needle deflection gets smaller, but the null (which is a simple comparison of metering cell resistance against a resistance selected by the ASA/speed dial) remains accurate (barring age-related problems with the dual CdS cells). I've used mine with silver oxide batteries for years, never a problem (though I don't shoot many slides) until coming up with an apparent shorted CdS cell recently.

    GMA's advice is correct for nearly every other battery operated meter of the day, however, whether installed in a camera or hand held -- most of them used mercury cells because of their long life and flat voltage curve as they discharged, and depend on the cell to provide a reference voltage; those require expensive and unreliable adapters, or short-lived zinc-air cells to give accurate results.

    Do watch polarity, though my 1967 SP only runs the meter in reverse (needle goes to minus with too much light) if I get the battery in backward. You can't reverse the original cell, but the modern ones, in an adapter, can be installed backward with a little effort...
     
  4. benjiboy

    benjiboy Subscriber

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    The Pentax Spotmatic used PX625 mercury battery which are no longer made, due to environmental issues with mercury, they have been replaced by Zinc Air one called a Wein cell,you can find by searching on Google
     
  5. resummerfield

    resummerfield Subscriber

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    Check eBay for Spotmatics and lenses. Right now the lenses are the cheapest I've seen, often $20-30. And quite a few sellers are in Canada.
     
  6. Steve Roberts

    Steve Roberts Member

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    Excellent cameras! Some fine photographs have been taken with the Spotmatic and its derivatives. I've always believed that every photographer should at some point own a Spotmatic. When I was getting interested in the early '70s they were beyond my pocket, but two days ago I bought another for my collection of Pentaxes (an SP2) in very good nick for ten quid (although they're cheap and easy to fix anyway). Excellent lenses, now to be had for peanuts on eBay, and even without the battery, all shutter speeds and are operative. As for the handling, I quote the adverts "Trust your hands to tell you it's Pentax!"
    Steve
     
  7. dr bob

    dr bob Member

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    Donald is correct, the bridge circuit in the meter of the SpotMatic is independent of the voltage and any approximately 1.5 volt cell will suffice. I tried the Zn/air cells with success but they constantly discharge as soon as the seal is removed. So it runs down whether you use the meter or not. They only lasted a month for me. I use a Ag/Zn now and check it against my spot meter regularly. It is a great camera - I even found a fa/2.8 Vivider 80-200 zoom. Never seen one before or after. According to my sources, that lens was made by a very reputable Japanese maker. Good luck - I'm sure you will enjoy the operation and the results.
     
  8. gma

    gma Member

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    I thought that the zinc/air batteries are supposed to last a year after the seal is opened. The only one I have used lasted almost exactly one year then failed completely without any warning. I bought a package of hearing aid batteries that read correctly for a split second then start dropping. Not at all reliable in my experience.
     
  9. titrisol

    titrisol Member

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    I use 395 batteries in mine, placed upside down. No problems so far.
     
  10. Nick Zentena

    Nick Zentena Member

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    I thought hearing aid batteries are zinc air?
     
  11. Donald Qualls

    Donald Qualls Member

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    Mine worked fine with silver oxide batteries -- the last one I had in there lasted almost two years before I accidentally left the meter on and ran it down. Now I have a bad CdS cell, so I'm shooting Sunny 16... :sad:
     
  12. Philippe-Georges

    Philippe-Georges Member

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    Good evening Uncle Bill,
    As I posted before, I am desperately looking for an electric cable release for a Pentax LX winder, could you help me with a hint?
    Much obliged,
    Philippe