Pentax K1000 Light Meter Adjustment

[KPT]

I just pick up another K1000 and found that the light meter is not correct. Is there an adjustment under the bottom cover for the meter or is the meter no good?

Thanks!

 

[nickandre]

Change the ISO to compensate. In short last time I brought a camera in for repair with the light meter ring squeaky and off by 2/3 stop they claimed it was fried and they had a lovely $200 camera body for me to try out.

 

[KPT]

Change the ISO to compensate. In short last time I brought a camera in for repair with the light meter ring squeaky and off by 2/3 stop they claimed it was fried and they had a lovely $200 camera body for me to try out.

How much would i compensate? The correct reading should be f4 125th iso400 but the second k1000 with incorrect meter is showing f4 250th iso400.

Thanks!

 

[nickandre]

that's an underexposure of 1 entire stop. how are you measuring this? you would change the ISO to 200 because that gives the film twice as much light. When I did mine I just adjusted the meter until I got optimal density on my negs.

 

[KPT]

One thing i forgot to mention is that the camera was sitting for several years before i got it. i had to remove the bottom plate to get access to the battery because the battery cover is frozen shut and wont turn. the connections for the battery were o.k because the battery leaked down and froze the cover. i put the battery from my other K1000 in this one thats when i found the meter to be incorrect. I dont know if any of this matters but i feel i should mention it.

Thanks.

 

[KPT]

that's an underexposure of 1 entire stop. how are you measuring this? you would change the ISO to 200 because that gives the film twice as much light. When I did mine I just adjusted the meter until I got optimal density on my negs.

Thank you for the advice! I will change the iso to 200 and see if its o.k but now i have the bottom plate soaking in oil to see if i can un-screw the battery cover.

Thanks!

 

[chriscrawfordphoto]

The camera body itself, the bottom cover and battery cover, serve as one of the cantacts in the circuitry of the K1000. If there is any corrosion on the bottom or the battery cover, it will cause incorrect readings

 

[KPT]

The camera body itself, the bottom cover and battery cover, serve as one of the cantacts in the circuitry of the K1000. If there is any corrosion on the bottom or the battery cover, it will cause incorrect readings

Thanks! That makes sense! The cover has some corrosion and i will clean it as soon as i can bust the cover loose from the bottom plate. Thanks again for that info!

 

[KPT]

that's an underexposure of 1 entire stop. how are you measuring this? .

I took the lens and battery from my K1000 that has a correct meter and put them on the new K1000. The new K1000 meter is requiring a 250th shutter speed compared to the good camera that requires only a 125th shutter speed.

 

[removed account4]

hi kpt

i have a k1000 that i got in 81? and the meter was never dead on.
the best exposures were when it was about 1stop off,
so the needle up towards the "+" about 1 stop ...
i still use my k1000, and love it

good luck getting the little battery cover off!

john

 

[Pinholemaster]

Meter readings are just a suggestion. Some films are never the ISO listed on the box. You can set the camera's ISO to whatever you want as long as the results match your vision. That said, if the meter is consistently off by 2/3 of a stop no matter what film you use, dial in the 2/3 correction instead of giving you money to a repair shop.

 

[Polybun]

I just pick up another K1000 and found that the light meter is not correct. Is there an adjustment under the bottom cover for the meter or is the meter no good?

Thanks!

On the k1000, you adjust its meter by soldering in and out resitors of differing values at specific points on the metering circut. What ever you do, don't touch the two variable resistors on the clc board! Those are there to correct linearity issues between the two clc's.

Easiest method, push the iso dial till you get the reading you want. Althougn, it is possible that one of the clc's has gone bad, or is block with dust. That will cause a reading error of exactly one stop every time! The only way to check this is to remove the clc board and desolder the clc's themselves and check them with an ohm meter of suffient imput impedance.

http://www.mypentax.com/K100Calibration.html

This is how it is done, don't even remove screw one unless you understand everything said on that page!

 

[Steve Smith]

I would try to compare them with a known good lightmeter. You have two identical cameras and you are assuming that your original one is correct and the new one is off by one stop. It could be the other way round.



Steve.

 

[KPT]

I would try to compare them with a known good lightmeter. You have two identical cameras and you are assuming that your original one is correct and the new one is off by one stop. It could be the other way round.



Steve.

Since i dont have a hand held meter i use the readings from my Canon Eos to set the exposure on my other cameras. The Canon and the K1000 that i refer to as (The Good One) has the exact same readings and also i use the Canon reading to set the exposure on my Mamiya C330F and my Speed Graphic and have been please with the results. I guess i should quit buying cameras and invest the money in a good hand held meter.

 

[Steve Smith]

How much would i compensate? The correct reading should be f4 125th iso400 but the second k1000 with incorrect meter is showing f4 250th iso400.

Is it a repeatable 1 stop out at other apertures?

i.e.

Camera 1.........Camera 2
f4 1/125..........f4 1/250
f5.6 1/60.........f5.6 1/125
f8 1/30............f8 1/60
f11 1/15..........f11 1/30
f16 1/8............f16 1/15

etc.

If not it could be the aperture coupling at fault rather than the light sensor.


Steve.

 

[KPT]

Update on the meter. After the cover and bottom plate was cleaned of all corrosion the meter is either 2 stops over or 2 stops under, it does what it wants to and its very slow to react when i change the shutter speed. When i used it in a brighter situation the meter is correct! My other k1000 meter is exact in dim or bright light. Did Pentax use different meters in the same model through out the years? The k1000 with the meter that is good in dim or bright situations has a serial #79xxxxx and the k1000 with the meter that goes nuts in dim situations has a serial #68xxxxx. The meter works great in bright situations.

 

[chriscrawfordphoto]

If it isn't linear after cleaning the corrosion it needs adjusted professionally. If its too expensive (and camera repair often is) then you could just use another meter and ignore whats in the camera

 

[John Koehrer]

The meter adjustment is under the top cover.
If the soak doesn't loosen the battery cover, you can drill two small holes in the cover & use a spanner or snap ring pliers to remove it. As a note though, snap ring pliers are very brittle & if the cover's tight enough they will break.

 

[Polybun]

Update on the meter. After the cover and bottom plate was cleaned of all corrosion the meter is either 2 stops over or 2 stops under, it does what it wants to and its very slow to react when i change the shutter speed. When i used it in a brighter situation the meter is correct! My other k1000 meter is exact in dim or bright light. Did Pentax use different meters in the same model through out the years? The k1000 with the meter that is good in dim or bright situations has a serial #79xxxxx and the k1000 with the meter that goes nuts in dim situations has a serial #68xxxxx. The meter works great in bright situations.

Sounds like one of the cds cells is dead. You'll want to send it off to a pro, unless your REALLY handy with a soldering iron, and have another k1000 to scrap for its cds board.

 

[waynecrider]

I have a body that I ahd cla'd and the bad meter replaced and it went bad after a short amount of time. It is definitely non-linear now or I'd being adjusting the ISO as well. An old acquaintance who I remembered works on Pentax told me that the meters are a pain to work on and it's not worth the money to get them fixed. Best solution is a handheld.

 

[John Koehrer]

Meters can be non-linear. There are as I recall both high and low light adjustments on the circuit board.
Several things can happen. Electronic components will age, the cell can age, the adjustment pots can become dirty or tarnished, a solder joint can become "cold" or even the wiring can be corroded. As in from the battery.
If I had the camera apart on my bench, the first thing I would do is clean the pots and the ISO resistor. second, touch up the solder joints related to the meter, third, suspect the wire or cell. When frustrated I'd consider drop-kicking the thing down the street. They're quite rugged, you know.

 

[Polybun]

Meters can be non-linear. There are as I recall both high and low light adjustments on the circuit board.
Several things can happen. Electronic components will age, the cell can age, the adjustment pots can become dirty or tarnished, a solder joint can become "cold" or even the wiring can be corroded. As in from the battery.
If I had the camera apart on my bench, the first thing I would do is clean the pots and the ISO resistor. second, touch up the solder joints related to the meter, third, suspect the wire or cell. When frustrated I'd consider drop-kicking the thing down the street. They're quite rugged, you know.

LOL christ i thought i was the only one! That little neck strap they came with, sure isn't worth a shit for anything else! You can really get one flying on the end of it though!

Yes there is a linearity adjustment on the cds board, thats what the two pots are for. BUT, if the cells are no longer somewhat matched, IE< one is starting to fail, you will never get it run linear.

Oh, the spotmatic seems a bit tougher than the k1000, GO GO SCREWMOUNT HAMMER!