Green Button Metering with Manual Lens

zombieCat · 02-14-2010, 01:59 PM

I'm in the process of trying to figure out the metering on my manual 50 f/1.7. I'm using the M mode on my K20D and using the green button to set the initial shutter speed. I saw a post the other day that mentioned the "Sunny 16" rule so I thought I'd try it out. Using f/16 at ISO 200, this guideline should put me at a speed of 1/250 (closest to 1/200). I found that's a bit underexposed, and that 1/180 seems to be the proper shutter speed with this lens. I hit the green button to see if it would set it to 1/180 rather than 1/250, and to my surprise, it set the shutter to 1/20. I tried various compositions, and the green button takes me to the 1/15-1/30 range. I stopped down to f/8 and found similar results. Here are a few examples (taken in full sun at round 1:00pm):

f/16, ISO200, 1/20 second (this is the speed the green button set)

f/16, ISO200, 1/180

f/8, ISO200, 1/30 second (this is the speed the green button set)

f/8, ISO200, 1/125

Why would my K20D's green button be setting the shutter so low? There's no exposure compensation, and I tried center-weighted and spot focusing, both of which had similar results.

Thanks,

jeff

indytax · 02-14-2010, 07:21 PM

No one definitively knows why some cameras meter inconsistently with pre-A manual lenses, but it's a well documented fact here in the Forums and elsewhere. The consensus is that the focusing screen causes a metering error with these legacy lenses. Some people have changed their screen to the one found in the *istD series cameras and found the metering to be improved. Do a search of the Forums and you will find many threads on the subject. My solution is to learn how your manual lenses meter and dial in EV comp (or adjusting shutter speed/ISO if in M mode on by K10D) as appropriate for the aperture.

JETninja · 02-14-2010, 11:15 PM

Same with my K200D, I just shoot a few to get an Idea of what the proper speed should be looking at the Pic & Histogram....I shoot a ton with old manual lenses....

zombieCat · 02-15-2010, 12:42 AM

Thanks for the replies indytax and JETninja. I should have been more diligent in using the search function. I think dialing in EV is the best solution. I'll put the lens to work to figure out what compensation for a given scenario. Thanks again.

**Lowell Goudge** · 02-15-2010, 06:07 AM

the K10D and K10D have very poor metering with manual lenses.

I made the following using my *istD, K10D and K7D. It seems to be highy related to the focusing screen on the K10D and K20D (they are the same)

02-14-2010, 01:59 PM	#1
zombieCat Forum Member Join Date: Nov 2009 Location: Idaho Posts: 95	Green Button Metering with Manual Lens I'm in the process of trying to figure out the metering on my manual 50 f/1.7. I'm using the M mode on my K20D and using the green button to set the initial shutter speed. I saw a post the other day that mentioned the "Sunny 16" rule so I thought I'd try it out. Using f/16 at ISO 200, this guideline should put me at a speed of 1/250 (closest to 1/200). I found that's a bit underexposed, and that 1/180 seems to be the proper shutter speed with this lens. I hit the green button to see if it would set it to 1/180 rather than 1/250, and to my surprise, it set the shutter to 1/20. I tried various compositions, and the green button takes me to the 1/15-1/30 range. I stopped down to f/8 and found similar results. Here are a few examples (taken in full sun at round 1:00pm): f/16, ISO200, 1/20 second (this is the speed the green button set) f/16, ISO200, 1/180 f/8, ISO200, 1/30 second (this is the speed the green button set) f/8, ISO200, 1/125 Why would my K20D's green button be setting the shutter so low? There's no exposure compensation, and I tried center-weighted and spot focusing, both of which had similar results. Thanks, jeff

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02-14-2010, 07:21 PM	#2
indytax Veteran Member Join Date: Jan 2009 Location: Indianapolis, Indiana, USA Photos: Gallery Posts: 312	No one definitively knows why some cameras meter inconsistently with pre-A manual lenses, but it's a well documented fact here in the Forums and elsewhere. The consensus is that the focusing screen causes a metering error with these legacy lenses. Some people have changed their screen to the one found in the *istD series cameras and found the metering to be improved. Do a search of the Forums and you will find many threads on the subject. My solution is to learn how your manual lenses meter and dial in EV comp (or adjusting shutter speed/ISO if in M mode on by K10D) as appropriate for the aperture.

02-14-2010, 11:15 PM	#3
JETninja Senior Member Join Date: Jul 2008 Location: Sammamish, WA Photos: Gallery Posts: 161	Same with my K200D, I just shoot a few to get an Idea of what the proper speed should be looking at the Pic & Histogram....I shoot a ton with old manual lenses....

02-15-2010, 12:42 AM	#4
zombieCat Forum Member Join Date: Nov 2009 Location: Idaho Posts: 95 Original Poster	Thanks for the replies indytax and JETninja. I should have been more diligent in using the search function. I think dialing in EV is the best solution. I'll put the lens to work to figure out what compensation for a given scenario. Thanks again.

02-15-2010, 06:07 AM	#5
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,144	the K10D and K10D have very poor metering with manual lenses. I made the following using my *istD, K10D and K7D. It seems to be highy related to the focusing screen on the K10D and K20D (they are the same)

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