Light Meter

sam.p · 08-02-2010, 12:34 PM - **1 Like**

Hello,
I'm having an issue with my light meter on my MX. Is there any way I can calibrate it without having to send it into a camera shop?

Thanks.

Adam · 08-02-2010, 12:55 PM

Not without opening the camera, no. Chances usually are that the battery is low- have you tried replacing it?

stevebrot · 08-02-2010, 01:08 PM

Most repair shops will check the calibration for you without charge. If you are in the Portland area, there are several shops that do good work.

Steve

sam.p · 08-02-2010, 02:35 PM

I have tried replacing the battery. I went to Blue moon camera and they said the light meter was off and the film advance wasn't the way they like it and that it would take $150 to fix it. I figure, since the film advance works I wanted to try to take care of the light meter myself. If not, thats fine. I want to sell the camera and some lenses.

stevebrot · 08-02-2010, 06:23 PM

Originally posted by sam.p

I have tried replacing the battery. I went to Blue moon camera and they said the light meter was off and the film advance wasn't the way they like it and that it would take $150 to fix it. I figure, since the film advance works I wanted to try to take care of the light meter myself. If not, thats fine. I want to sell the camera and some lenses.

Blue Moon is pretty good, though Eric would probably charge about half that. I would not suggest the do-it-yourself route on any camera that has any potential value. Even meter calibration often requires balancing multiple "pots" against a standardized light source. Unless you know what you are doing, the moment you pop the top cover off and start messing with things, all bets are off the camera ever going back together the way it is supposed to be. Did I mention too, that special tools are needed? Those eety beety screws...well, they are not phillips head.

If you want to sell the camera rather than getting it fixed, I might be willing to buy it from you for parts value.

BTW...Welcome to the Pentax Forums!

Steve

(Just got done doing a bit of minor surgery on my Lynx 1000...not fun, but I have two parts bodies that I used to practice on first.)

**pacerr** · 08-02-2010, 07:42 PM

Originally posted by sam.p

Hello,
I'm having an issue with my light meter on my MX. Is there any way I can calibrate it . . .

You didn't say what sort of miss-calibration you were experiencing. If the exposure is consistently and linearly off (high or low) it may be dirty contacts in the ASA (ISO) setting mechanism. Just exercising the dial might solve the problem. Unfortunately, the electrical contacts aren't as accessible for cleaning in the MX as they are in the ME/K1000/SP bodies.

If the issue isn't linear throughout the exposure range, or varies with exposure settings, the issue may be with either the aperture (lens) or shutter mechanism (camera) -- or both.

You can define the problem fairly simply by making an exposure table and taking readings of the clear north sky. Readings should follow the standard reciprocal pattern of speed versus aperture. You might also do a comparison with a second light meter or TTL camera as a confidence factor.

Define your exposure error through trial first. You may find an internal calibration isn't the solution. As a user camera, sometimes just compensating a known EV error with the ASA dial is the easy/economical solution (even if it's not a linear error).

H2

sam.p · 08-02-2010, 09:54 PM

Originally posted by ChrisPlatt

Suggest you send it to Eric Hendrickson.
He charges much less, about half what you were quoted.
It will come back working like new.

Link: Camera Repair by Eric Hendrickson

Chris

Thanks but no thanks. From Eric's website, it looks like he's in Tennessee which is out of the question for me. It would be nice if there was someone in Portland like Eric.

The issue that was pointed out to me was that the meter was showing a shutter speed of 60 and the film speed setting was 400, which isn't correct.

Portland Pete · 08-03-2010, 03:26 AM

Your example of ISO 400 and 1/60 seems to be missing a couple pieces. What light and aperture were used to obtain that reading? I like the folks a Blue Moon, and will usually spend the extra money because its a local North Portland business, but I sent my SV to Eric and it was well worth it. He charges just about half of what they want at Blue Moon, which includes return shipping.

PS: There is a Portland Pentaxians group on the forums started by SteveBrot. Check it out.

sam.p · 08-04-2010, 04:46 PM

The aperture was completely open at about 2.4, I'm not too sure of the f stop. I pointed the camera at the blue sky on a sunny day.

Portland Pete · 08-05-2010, 08:48 AM

That does sound like its reading pretty slow. Sunny 16 tells us f/16 at 1/500 [400 for ISO 400 film in broad daylight. You might try Knight's Camera in Vancouver for the service if you want to stay local. They are at about 103rd and Mill Plain. Out of curiosity, why is Tennessee out of the question?

Pete

**pacerr** · 08-05-2010, 03:51 PM - **1 Like**

I'd only hijack it on the way by for a few days to see if it'd mate with mine. If it works, I'd give you second choice of the litter.

H2

08-02-2010, 12:34 PM - 1 Like	#1
sam.p New Member Join Date: Aug 2010 Location: Oregon Posts: 5	Light Meter Hello, I'm having an issue with my light meter on my MX. Is there any way I can calibrate it without having to send it into a camera shop? Thanks.

08-02-2010, 12:55 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Not without opening the camera, no. Chances usually are that the battery is low- have you tried replacing it? Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

08-02-2010, 07:42 PM	#6
pacerr Loyal Site Supporter Join Date: Jan 2008 Location: Paris, TN Photos: Gallery \| Albums Posts: 3,350	Depends Originally posted by sam.p Hello, I'm having an issue with my light meter on my MX. Is there any way I can calibrate it . . . You didn't say what sort of miss-calibration you were experiencing. If the exposure is consistently and linearly off (high or low) it may be dirty contacts in the ASA (ISO) setting mechanism. Just exercising the dial might solve the problem. Unfortunately, the electrical contacts aren't as accessible for cleaning in the MX as they are in the ME/K1000/SP bodies. If the issue isn't linear throughout the exposure range, or varies with exposure settings, the issue may be with either the aperture (lens) or shutter mechanism (camera) -- or both. You can define the problem fairly simply by making an exposure table and taking readings of the clear north sky. Readings should follow the standard reciprocal pattern of speed versus aperture. You might also do a comparison with a second light meter or TTL camera as a confidence factor. Define your exposure error through trial first. You may find an internal calibration isn't the solution. As a user camera, sometimes just compensating a known EV error with the ASA dial is the easy/economical solution (even if it's not a linear error). H2

08-05-2010, 03:51 PM - 1 Like	#11
pacerr Loyal Site Supporter Join Date: Jan 2008 Location: Paris, TN Photos: Gallery \| Albums Posts: 3,350	[B]Yeah, why is Tennessee out of the question?[/B] I'd only hijack it on the way by for a few days to see if it'd mate with mine. If it works, I'd give you second choice of the litter. H2

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
K-x as a light meter	Eagle_Friends	Pentax DSLR Discussion	7	10-15-2010 05:32 AM
Help with light meter	srpickel	Troubleshooting and Beginner Help	6	02-18-2010 03:49 PM
Light Meter	daacon	Pentax Camera and Field Accessories	16	12-25-2009 10:09 PM
Using the K-m light meter - if it has one	kitkat	Troubleshooting and Beginner Help	14	07-11-2009 06:23 PM
recommend a light meter	volosong	Pentax Camera and Field Accessories	7	12-14-2006 12:49 AM

08-02-2010, 01:08 PM	#3
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Most repair shops will check the calibration for you without charge. If you are in the Portland area, there are several shops that do good work. Steve

08-02-2010, 02:35 PM	#4
sam.p New Member Join Date: Aug 2010 Location: Oregon Posts: 5 Original Poster	I have tried replacing the battery. I went to Blue moon camera and they said the light meter was off and the film advance wasn't the way they like it and that it would take $150 to fix it. I figure, since the film advance works I wanted to try to take care of the light meter myself. If not, thats fine. I want to sell the camera and some lenses.

08-02-2010, 06:23 PM	#5
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by sam.p I have tried replacing the battery. I went to Blue moon camera and they said the light meter was off and the film advance wasn't the way they like it and that it would take $150 to fix it. I figure, since the film advance works I wanted to try to take care of the light meter myself. If not, thats fine. I want to sell the camera and some lenses. Blue Moon is pretty good, though Eric would probably charge about half that. I would not suggest the do-it-yourself route on any camera that has any potential value. Even meter calibration often requires balancing multiple "pots" against a standardized light source. Unless you know what you are doing, the moment you pop the top cover off and start messing with things, all bets are off the camera ever going back together the way it is supposed to be. Did I mention too, that special tools are needed? Those eety beety screws...well, they are not phillips head. If you want to sell the camera rather than getting it fixed, I might be willing to buy it from you for parts value. BTW...Welcome to the Pentax Forums! Steve (Just got done doing a bit of minor surgery on my Lynx 1000...not fun, but I have two parts bodies that I used to practice on first.)

08-02-2010, 09:54 PM	#7
sam.p New Member Join Date: Aug 2010 Location: Oregon Posts: 5 Original Poster	Originally posted by ChrisPlatt Suggest you send it to Eric Hendrickson. He charges much less, about half what you were quoted. It will come back working like new. Link: Camera Repair by Eric Hendrickson Chris Thanks but no thanks. From Eric's website, it looks like he's in Tennessee which is out of the question for me. It would be nice if there was someone in Portland like Eric. The issue that was pointed out to me was that the meter was showing a shutter speed of 60 and the film speed setting was 400, which isn't correct.

08-03-2010, 03:26 AM	#8
Portland Pete Senior Member Join Date: Dec 2009 Location: Oregon Photos: Albums Posts: 144	Your example of ISO 400 and 1/60 seems to be missing a couple pieces. What light and aperture were used to obtain that reading? I like the folks a Blue Moon, and will usually spend the extra money because its a local North Portland business, but I sent my SV to Eric and it was well worth it. He charges just about half of what they want at Blue Moon, which includes return shipping. PS: There is a Portland Pentaxians group on the forums started by SteveBrot. Check it out.

08-04-2010, 04:46 PM	#9
sam.p New Member Join Date: Aug 2010 Location: Oregon Posts: 5 Original Poster	The aperture was completely open at about 2.4, I'm not too sure of the f stop. I pointed the camera at the blue sky on a sunny day.

08-05-2010, 08:48 AM	#10
Portland Pete Senior Member Join Date: Dec 2009 Location: Oregon Photos: Albums Posts: 144	That does sound like its reading pretty slow. Sunny 16 tells us f/16 at 1/500 [400 for ISO 400 film in broad daylight. You might try Knight's Camera in Vancouver for the service if you want to stay local. They are at about 103rd and Mill Plain. Out of curiosity, why is Tennessee out of the question? Pete