Is there a way to calibrate a Pentax ESII meter at home?

[Tim Murphy]

Dear Board,

I had the camera refurbished by highly reputable someone 2 years ago and 3 exposures into the roll I realized that the meter was easily reading 2 to 3 stops high, sometimes even higher. I haven't even finished the roll of film in it. I should have returned it but sadly I didn't and wonder if it is even worth the bother anymore.

Metering this exact screen with ISO 200 film in the camera it reads 1/500th at f1.8. A Gossen Luna-Pro F and both a known good Pentax ME Super and Nikon FTN read 1/60th at f1.8. Clearly something is off.

I am wondering if there is a simple adjustment on the camera to tone things down, and if anyone can talk me through it or provide instructions?

Regards,

Tim Murphy

Harrisburg PA 🙂

 

[Tim Murphy]

Dear Board,

I contacted a camera repair service that I had used previously, and the owner emailed me a suggestion for a work-around. It's so simple that I appreciate that he didn't call me a dummy for not trying it myself. The simple fix of using a known good meter and obtaining a reading and then changing the ISO on the ESII to get the same result shows that with ISO 200 film in the camera the meter is correct when the ISO is set to 32.

I'll monitor the situation and make adjustments accordingly when I change the film loaded in the camera. Since I mostly shoot 100, 200, or 400 ISO film everything should be OK, and I won't need to spend more money so that's a win for me! 😉

Regards,

Tim Murphy

Harrisburg PA 🙂

 

[bjolester]

iFixit have "how to repair" guides for several Pentax cameras:
Pentax Camera Repair Help: Learn How to Fix It Yourself.

There is also a guide how to calibrate the lightmeter on the Pentax Spotmatic:
Pentax Spotmatic Light Meter Calibration

*Some of these guides have been written by a very knowledable member (vandergus) of Pentaxforums.com

 

[Chriscrawfordphoto]

The problem with the 'change the ISO' method is that it usually doesn't work. Meters almost NEVER simply become off by a certain amount. What actually happens is they become non-linear, meaning that the amount of error varies depending on the light level. It needs to be properly repaired, and may need the meter cells replaced, as they become less linear with age.

 

[Tim Murphy]

The problem with the 'change the ISO' method is that it usually doesn't work. Meters almost NEVER simply become off by a certain amount. What actually happens is they become non-linear, meaning that the amount of error varies depending on the light level. It needs to be properly repaired, and may need the meter cells replaced, as they become less linear with age.

Dear Chris,

That is precisely what I paid to have done to the camera when I sent it for repair. Upon first receiving the camera it appeared all was in order. But when I began to use the camera several months later it was clear something was wrong. Replacing the batteries still yielded exposure readings that were at least 2 to 3 stops high in all cases. Clearly the issue is with the repair that was done and paying for it a second time is not a sensible option to me. Having close to $ 400.00 in repair bills for a camera I paid $ 50.00 for when I bought it just doesn't work, especially when I have an $ 18.00 Goodwill Spotmatic F that works perfectly.

I like to have fully operational gear, but I also have financial and practical limits to consider. I just thought the ESII might be a neat addition, but it may wind up being a display piece as time goes on.

In the meantime, checking the meter against a known good meter and adjusting the ISO on the camera to match when I use it should be more than sufficient for my occasional use. I may investigate the repair guide bjolester provided, but for now I suspect I'll be OK doing as was suggested, and in the worst case I'll try shooting sunny f16 if that doesn't work out.

Regards,

Tim Murphy

Harrsiburg PA 🙂

 

[bjolester]

In the meantime, checking the meter against a known good meter and adjusting the ISO on the camera to match when I use it should be more than sufficient for my occasional use. I may investigate the repair guide bjolester provided, but for now I suspect I'll be OK doing as was suggested, and in the worst case I'll try shooting sunny f16 if that doesn't work out.

Regards,

Tim Murphy

Harrsiburg PA 🙂

I tend to use a lightmeter app on my iPhone when photographing with my Pentax Spotmatic, KX or MX. It is less convenient but more precise. I use this app:

Pocket Light Meter

 

[Retro-Grouch]

The problem with the 'change the ISO' method is that it usually doesn't work. Meters almost NEVER simply become off by a certain amount. What actually happens is they become non-linear, meaning that the amount of error varies depending on the light level. It needs to be properly repaired, and may need the meter cells replaced, as they become less linear with age.

What Chris says is very true. But it's very easy to check whether the error is non-linear. Take a camera reading in moderate light and adjust the camera's ISO until the camera's meter reading matches that of a known accurate meter set to, say, ISO 100, with the identical subject. Then take a reading in low light, and another in very bright light, both without changing the ISO of either meter. If the error is linear, then your camera's meter reading under the dimmer and brighter conditions will still match that of the accurate meter when both are pointed at the same subject. In that case you are lucky, and the camera's meter cell hasn't deteriorated. Fingers crossed!

 

[Tim Murphy]

I tend to use a lightmeter app on my iPhone when photographing with my Pentax Spotmatic, KX or MX. It is less convenient but more precise. I use this app:

Pocket Light Meter

Dear bjolester,

I had that on my iPhone but have since replaced that phone with an Android phone and that app is not compatible. I do have an Android light meter app. Coincidently, it when set to ISO 200 it exactly matches the readings I get from the ESII when it is set to ISO 32. I may dig up my old Apple 5C and charge it to see if the app still works.

Regards,

Tim Murphy

Harrisburg PA 🙂

 

[Chriscrawfordphoto]

Dear Chris,

That is precisely what I paid to have done to the camera when I sent it for repair. Upon first receiving the camera it appeared all was in order. But when I began to use the camera several months later it was clear something was wrong. Replacing the batteries still yielded exposure readings that were at least 2 to 3 stops high in all cases. Clearly the issue is with the repair that was done and paying for it a second time is not a sensible option to me. Having close to $ 400.00 in repair bills for a camera I paid $ 50.00 for when I bought it just doesn't work, especially when I have an $ 18.00 Goodwill Spotmatic F that works perfectly.

I like to have fully operational gear, but I also have financial and practical limits to consider. I just thought the ESII might be a neat addition, but it may wind up being a display piece as time goes on.

In the meantime, checking the meter against a known good meter and adjusting the ISO on the camera to match when I use it should be more than sufficient for my occasional use. I may investigate the repair guide bjolester provided, but for now I suspect I'll be OK doing as was suggested, and in the worst case I'll try shooting sunny f16 if that doesn't work out.

Regards,

Tim Murphy

Harrsiburg PA 🙂

Damn, I'd have asked the repairer to fix it again!

 

[Tim Murphy]

Damn, I'd have asked the repairer to fix it again!

Dear Chris,

I sent you a PM with more information just so you understand better the situation I am in with the camera.

Thanks for the discussion, and information about metering systems.

Regards,

Tim Murphy

Harrisburg PA 🙂