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Possible problem with my Pentax K1000 light meter?

Robert Pyon , Jan 09, 2010; 08:29 p.m.

I bought a Pentax K1000 a little over a month ago. All the controls seem to work properly, but I think there's a problem with my light meter. When I set the camera to ISO 100 and the shutter speed to B, the meter needle tends to go all the way up to the "+" side of the scale, which is as it should be. However, the needle moves at certain shutter speeds, but stands stock still at others. The same thing happens when I use the aperture ring.
Another thing that bugs me is that when I manage to get the needle centered, cocking the rapid wind lever and/or pressing the shutter button causes the needle to move off-center.
I've tried cleaning the batter cover and contact points as well as the battery itself. I've even switched out the batteries and still get the same problem.

I've heard the Pentax K1000's light meter is slow to respond, but I don't think that is the problem I'm having here.

Can someone help me out?


John Shriver , Jan 09, 2010; 09:42 p.m.

Have a look at this page , which has the National Camera service manual for the K1000. Sounds like there's a problem with the resistor that reads out the sum of shutter speed and film speed. You could be lucky, and someone assembled it wrong, "out of sync". You could be unlucky, and that resistor is worn out or broken. I doubt Pentax still sells spare parts for the K1000.
Good affordable repair service at http:/www.pentaxs.com. But another K1000 might be cheaper than repairs, they are common, although the "camera course" phenomenon causes them to fetch a somewhat inflated price. (An MX, KX, or K2 are really better cameras, and often cheaper. But the K1000 is a nice camera.)

John O'Keefe-Odom , Jan 10, 2010; 11:45 a.m.

Sometimes it helps to "wake up" the light meter by rotating through some shutter speeds.

This problem could manifest itself under normal operating conditions, without much mechanical trouble from the camera. Try using a basic TtL metering procedure to match the equipment up better. One suggested below.

Think also of the concept of key f/stop for light metering. Some of that is addressed in "The Negative" by Ansel Adams. The key f/stop for metering is the aperture number that is closest to the square root of the film speed number. For example, if you were using 100ASA film, the square root of 100 is 10. Ten is between f/11 and f/8. I would begin metering at f/8 because it is the closest f/stop which would allow enough light to strike the film. f/11 would be slightly too small.

From the key f/stop, make your adjustments to meet your exposure needs. It's common to have to extrapolate the answer after reading.

  • Measure the light at the key f/stop to determine shutter
  • Extrapolate that reading to suit your photographing conditions (f/stop for metering against f/stop for making the picture, for example. You may not be metering at the same optical settings you prefer for making the photograph itself with a basic TtL meter.)
  • Add in increases or decreases in the amount of light for tonal shifts or other factors not yet accounted for
  • Make the picture.

Using that method, you can smoothly operate the more basic light meters. Some of the crudest will be little more than a photocell with a battery and a needle gauge, like on the Yashicamat TLRs. [Obviously, not a TtL meter, but I offer it as an example of its very basic solid state electronics.]

It's the choosing of an aperture at key f/stop that's helping to eliminate other, usually stronger-lit, answers from the solution set. It'll keep you from accidentally overexposing as much. That is, of the ones that the basic light meter will tell you are "okay" exposures, the one at the key f/stop will usually be the one that lets in the least amount of light and still register the needle at the mid-point mark. You're still going to have to use your judgement, but that's one method you can use.

John O'Keefe-Odom , Jan 10, 2010; 12:06 p.m.

The reason why the key f/stop idea works is because [,I think,] the logic of the solid state electronics is aimed more at the idea of, Do you have enough light to meet the minimum requirement of attaining mid-tone gray (18% reflective card) at that film speed?

They will register an overexposure; but, the circuit is more logically accurate for scrutinizing whether or not the minimum amount of light required is present.

Caveat: [Keep in mind, this has been my hypothesis behind understanding the logic of the old key f/stop method. I could be wrong about the reasons, but I have observed that it works with a tendency that way. I read about the method, and tried it with the older style of TtL meters and got good results. With more advanced metering systems, like in a DSLR or other metering system with ICs, I haven't seen this method have the same impact. I suspect that advances in design made the necessity for the operator to do this math obsolete. I suspect that later designs of light meters did a better job of limiting the answer in a way that excluded the too much light side of things.]

The meter in the K1000/Spotmatics will still work just fine without the key f/stop idea, but key f/stop helps to filter out some of the extraneous answers that might misguide an operator to the wrong solution.

Don Coppola , Jan 11, 2010; 02:50 p.m.

The idea of cleaning the pots by running back & forth between the settings might help. If not , then the top will have to come off to check the wiring. If the needle ctrs. w/o moving when changing aperture or shutter spd, then no power is going thru the circuit. Your problem could be an open or oxidation on the pots or a loose wire (bad solder connection). Best to take to a tech. Another thing to check is the black wire going to the battery box. You might have a loose connection (fairly common) where it makes intermittent contact. Again, this would cause the needle to ctr. The meter isnt any slower to respond than any other brand using cds cells.

Robert Pyon , Jan 11, 2010; 09:23 p.m.

Hey guys,
Thanks for your responses. Right now, I'm trying to decide between sending my K1000 for repairs or buying a handheld light meter. I've heard I can get my camera fixed like new at pentaxs.com for about $65, but it might be cheaper to buy a handheld light meter. Any suggestions on which route I should take?

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