Re: My light meter working OK?
The one thing I would add to my own comments below is to consider the lens you are using on the camera... Some lenses meter less accurately than others, and F-Stops are not T-Stops and things like light fall off, the numbers of elements int he lenses, etc can have an effect on the exposure. (F Stops are calibrated to aperture size, T-Stops are calibrated to actual light transmission.) It should all be minimal but if you are having unusual results try a different lens and see what happens. MCC On 5/25/2012 10:53 PM, Mark C wrote: If I were testing the meters, I'd do the following: 1. Be sure to compare both meters in spot metering mode. You probably did this but just in case... 2. Verify what the 'spot' in the spot metering is. Put a small saucer sized white paper plate on a piece of black foam core. With the K5 - fill the frame with the plate and then slowly walk away from it, letting the black foam core start to fill the frame. Keep the paper plate centered in the finder - you will see the meter reading stay steady and then rapidly change as the plate gets smaller than the area being metered. You can verify that the "spot" being measured correlates the to the circle in the center of the frame. You could do that with the Sekonic as well. 3. Test both the K5 and Sekonic on a gray card, using your knowledge of the size of the spots to be sure that you are only metering off the grey card. 4. If there is a material difference in the readings off the gray card, then test the meters off a gray card in direct noon sunlight and compare to the sunny 16 rule. Hopefully one of the meters will comply with that. 5. Use the meter that complies with sunny 16 to work up an adjustment factor for the other. 6. Spot meter off various colored items and see if the meters perform consistently. If they vary, they may be more or less sensitive to different colors. This can be a bugger because you have no control point. One meter may be more sensitive to green, another to red, you can't use one to calibrate the other. You can try the sunny 16 rule with different colors, of course.. Are you shooting slide film, color neg, or silver B&W? If B&W, I'd just go out and shoot, take notes (mental or otherwise) and compensate the workflow. That means tweaking your metering / film ISO setting (same thing), your development times and agitation regimen. Use the data printed along the edge of the film as a control point for developing. If you are shooting slide film you have to be more careful with metering. Here's a story about metering and slide film: I visited the beach with a friend of mine one day, and we both shot this lighthouse: http://www.markcassino.com/newsite/portfolios/lighthouses/pages/0204l07.htm He had a Nikon F5 with a super sophisticated evaluative / color corrected metering system that he relied on. I had a Pz-1p. I spot metered off the black metal frame, did some quick zone calcs in my head, and set the exposure manually. We both shot ISO 100 slide film (him Provia, me E100S.) My shots came out very well - maybe 1/4 to 1/2 stop over exposed, but very usable. His were a mess. SO taking control of metering with film is important. Good luck! MCC On 5/21/2012 8:27 PM, Kenton Brede wrote: I'm making a foray into film and decided I should get a light meter. I bought a used Sekonic L-508 which has both incident and spot metering. Messing around with the K-5 and Sekonic, I found the readings didn't really match up. So I took a picture of the blue sky, the histogram was spiked in the center. I then spot metered the sky. I used the compensation function to dial in 3AV to bring the meter in line with the K-5's shutter, ISO and aperture. I used a gray card in the shade to meter off of with the K-5, and then matched those settings on the Sekonic by dialing in a -1AV for the incident reading. Does this sound like a decent calibration method? I went around metering things and taking shots with the K-5. I found that if I spot metered off a shaded green bush, I needed to speed up the shutter 2 stops to bring the histogram near center. When metering off a gray cloud, with silver lining, I sped up the shutter a couple stops to bring the histogram to center. The incident meter seemed to get the K-5 in the ballpark when metering in front of a tan shed, while the meter was facing the direction the sun. In shade, facing away from the sun, I generally had to slow the shutter down a couple stops. Does this sound like the way an accurate light meter works? I've never used one. Any thoughts appreciated. I realize all this hinges on the K-5 being accurate, and assuming the film cameras will work with the same meter readout as the K-5. I probably should have just purchased a new model, but good ones are expensive! Thanks, -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link di
RE: My light meter working OK?
[...] > > 3. Test both the K5 and Sekonic on a gray card, using your knowledge > of the size of the spots to be sure that you are only metering off the > grey card. > > 4. If there is a material difference in the readings off the gray > card, then test the meters off a gray card in direct noon sunlight and > compare to the sunny 16 rule. Hopefully one of the meters will comply > with that. > > 5. Use the meter that complies with sunny 16 to work up an adjustment > factor for the other. > Well though out, but I don't think that's precise enough to get an > accurate calibration. Sunlight intensity varies by the season and by > atmospheric conditions. The only way to be sure a meter is accurate is > to have it checked by a professional calibration service. Quality Light > Metric in L.A. 323-467-2265 is among the very best. They calibrate > meters for many of the DPs who work in the film industry. > > Paul That's not really necessary if the object of the exercise is to understand how the cameras and meter relate to each other, although it is of course useful in its own right. I've started replies to this question several times, and given up each time because giving a full and (hopefully useful) reply takes such a long time - email is not the best medium for extensive stuff like this. There is a site here which is pretty good advice about calibrating the meter, but it involves studio lights rather than sunny-16: http://www.frankdoorhof.com/site/2011/08/calibrating-the-light-meter-some-qu ick-notes/ The method I was trying to describe in my abortive replies was based around sunny-16 but it foundered when it came to checking the results against rgb values in Lightroom or similar because you need to know the light temperature to get a reference point. Studio lights overcome this. Even so, there seem to me to be 2 aspects to the calibration. One is trying to make sure that each meter recommends the same settings in the same light conditions, the other is making sure that all your cameras get the same results at the same settings. Or knowing what to adjust and when to ensure that you get consistent & predictable results. And while I think its possible to do this in a home-workshop sort of way, I've found myself getting too bogged down in the description to be any use... So my recommendation is lots of thought and googlage. B -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: My light meter working OK?
On May 25, 2012, at 10:53 PM, Mark C wrote: > If I were testing the meters, I'd do the following: > > 1. Be sure to compare both meters in spot metering mode. You probably did > this but just in case... > 2. Verify what the 'spot' in the spot metering is. Put a small saucer sized > white paper plate on a piece of black foam core. With the K5 - fill the frame > with the plate and then slowly walk away from it, letting the black foam core > start to fill the frame. Keep the paper plate centered in the finder - you > will see the meter reading stay steady and then rapidly change as the plate > gets smaller than the area being metered. You can verify that the "spot" > being measured correlates the to the circle in the center of the frame. You > could do that with the Sekonic as well. > 3. Test both the K5 and Sekonic on a gray card, using your knowledge of the > size of the spots to be sure that you are only metering off the grey card. > 4. If there is a material difference in the readings off the gray card, then > test the meters off a gray card in direct noon sunlight and compare to the > sunny 16 rule. Hopefully one of the meters will comply with that. > 5. Use the meter that complies with sunny 16 to work up an adjustment factor > for the other. Well though out, but I don't think that's precise enough to get an accurate calibration. Sunlight intensity varies by the season and by atmospheric conditions. The only way to be sure a meter is accurate is to have it checked by a professional calibration service. Quality Light Metric in L.A. 323-467-2265 is among the very best. They calibrate meters for many of the DPs who work in the film industry. Paul > 6. Spot meter off various colored items and see if the meters perform > consistently. If they vary, they may be more or less sensitive to different > colors. This can be a bugger because you have no control point. One meter may > be more sensitive to green, another to red, you can't use one to calibrate > the other. You can try the sunny 16 rule with different colors, of course.. > > Are you shooting slide film, color neg, or silver B&W? > > If B&W, I'd just go out and shoot, take notes (mental or otherwise) and > compensate the workflow. That means tweaking your metering / film ISO setting > (same thing), your development times and agitation regimen. Use the data > printed along the edge of the film as a control point for developing. If you > are shooting slide film you have to be more careful with metering. > > Here's a story about metering and slide film: > > I visited the beach with a friend of mine one day, and we both shot this > lighthouse: > > http://www.markcassino.com/newsite/portfolios/lighthouses/pages/0204l07.htm > > He had a Nikon F5 with a super sophisticated evaluative / color corrected > metering system that he relied on. I had a Pz-1p. I spot metered off the > black metal frame, did some quick zone calcs in my head, and set the exposure > manually. We both shot ISO 100 slide film (him Provia, me E100S.) My shots > came out very well - maybe 1/4 to 1/2 stop over exposed, but very usable. His > were a mess. SO taking control of metering with film is important. > > Good luck! > > MCC > > > > > On 5/21/2012 8:27 PM, Kenton Brede wrote: >> I'm making a foray into film and decided I should get a light meter. >> I bought a used Sekonic L-508 which has both incident and spot >> metering. Messing around with the K-5 and Sekonic, I found the >> readings didn't really match up. So I took a picture of the blue sky, >> the histogram was spiked in the center. I then spot metered the sky. >> I used the compensation function to dial in 3AV to bring the meter in >> line with the K-5's shutter, ISO and aperture. I used a gray card in >> the shade to meter off of with the K-5, and then matched those >> settings on the Sekonic by dialing in a -1AV for the incident reading. >> >> Does this sound like a decent calibration method? >> >> I went around metering things and taking shots with the K-5. I found >> that if I spot metered off a shaded green bush, I needed to speed up >> the shutter 2 stops to bring the histogram near center. When metering >> off a gray cloud, with silver lining, I sped up the shutter a couple >> stops to bring the histogram to center. The incident meter seemed to >> get the K-5 in the ballpark when metering in front of a tan shed, >> while the meter was facing the direction the sun. In shade, facing >> away from the sun, I generally had to slow the shutter down a couple >> stops. >> >> Does this sound like the way an accurate light meter works? I've >> never used one. >> >> Any thoughts appreciated. I realize all this hinges on the K-5 being >> accurate, and assuming the film cameras will work with the same meter >> readout as the K-5. I probably should have just purchased a new >> model, but good ones are expensive! >> Thanks, >> > > > -- > PDML Pentax-Discuss Mail List >
Re: My light meter working OK?
If I were testing the meters, I'd do the following: 1. Be sure to compare both meters in spot metering mode. You probably did this but just in case... 2. Verify what the 'spot' in the spot metering is. Put a small saucer sized white paper plate on a piece of black foam core. With the K5 - fill the frame with the plate and then slowly walk away from it, letting the black foam core start to fill the frame. Keep the paper plate centered in the finder - you will see the meter reading stay steady and then rapidly change as the plate gets smaller than the area being metered. You can verify that the "spot" being measured correlates the to the circle in the center of the frame. You could do that with the Sekonic as well. 3. Test both the K5 and Sekonic on a gray card, using your knowledge of the size of the spots to be sure that you are only metering off the grey card. 4. If there is a material difference in the readings off the gray card, then test the meters off a gray card in direct noon sunlight and compare to the sunny 16 rule. Hopefully one of the meters will comply with that. 5. Use the meter that complies with sunny 16 to work up an adjustment factor for the other. 6. Spot meter off various colored items and see if the meters perform consistently. If they vary, they may be more or less sensitive to different colors. This can be a bugger because you have no control point. One meter may be more sensitive to green, another to red, you can't use one to calibrate the other. You can try the sunny 16 rule with different colors, of course.. Are you shooting slide film, color neg, or silver B&W? If B&W, I'd just go out and shoot, take notes (mental or otherwise) and compensate the workflow. That means tweaking your metering / film ISO setting (same thing), your development times and agitation regimen. Use the data printed along the edge of the film as a control point for developing. If you are shooting slide film you have to be more careful with metering. Here's a story about metering and slide film: I visited the beach with a friend of mine one day, and we both shot this lighthouse: http://www.markcassino.com/newsite/portfolios/lighthouses/pages/0204l07.htm He had a Nikon F5 with a super sophisticated evaluative / color corrected metering system that he relied on. I had a Pz-1p. I spot metered off the black metal frame, did some quick zone calcs in my head, and set the exposure manually. We both shot ISO 100 slide film (him Provia, me E100S.) My shots came out very well - maybe 1/4 to 1/2 stop over exposed, but very usable. His were a mess. SO taking control of metering with film is important. Good luck! MCC On 5/21/2012 8:27 PM, Kenton Brede wrote: I'm making a foray into film and decided I should get a light meter. I bought a used Sekonic L-508 which has both incident and spot metering. Messing around with the K-5 and Sekonic, I found the readings didn't really match up. So I took a picture of the blue sky, the histogram was spiked in the center. I then spot metered the sky. I used the compensation function to dial in 3AV to bring the meter in line with the K-5's shutter, ISO and aperture. I used a gray card in the shade to meter off of with the K-5, and then matched those settings on the Sekonic by dialing in a -1AV for the incident reading. Does this sound like a decent calibration method? I went around metering things and taking shots with the K-5. I found that if I spot metered off a shaded green bush, I needed to speed up the shutter 2 stops to bring the histogram near center. When metering off a gray cloud, with silver lining, I sped up the shutter a couple stops to bring the histogram to center. The incident meter seemed to get the K-5 in the ballpark when metering in front of a tan shed, while the meter was facing the direction the sun. In shade, facing away from the sun, I generally had to slow the shutter down a couple stops. Does this sound like the way an accurate light meter works? I've never used one. Any thoughts appreciated. I realize all this hinges on the K-5 being accurate, and assuming the film cameras will work with the same meter readout as the K-5. I probably should have just purchased a new model, but good ones are expensive! Thanks, -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: My light meter working OK?
If I were testing the meters, I'd do the following: 1. Be sure to compare both meters in spot metering mode. You probably did this but just in case... 2. Verify what the 'spot' in the spot metering is. Put a small saucer sized white paper plate on a piece of black foam core. With the K5 - fill the frame with the plate and then slowly walk away from it, letting the black foam core start to fill the frame. Keep the paper plate centered in the finder - you will see the meter reading stay steady and then rapidly change as the plate gets smaller than the area being metered. You can verify that the "spot" being measured correlates the to the circle in the center of the frame. You could do that with the Sekonic as well. 3. Test both the K5 and Sekonic on a gray card, using your knowledge of the size of the spots to be sure that you are only metering off the grey card. 4. If there is a material difference in the readings off the gray card, then test the meters off a gray card in direct noon sunlight and compare to the sunny 16 rule. Hopefully one of the meters will comply with that. 5. Use the meter that complies with sunny 16 to work up an adjustment factor for the other. 6. Spot meter off various colored items and see if the meters perform consistently. If they vary, they may be more or less sensitive to different colors. This can be a bugger because you have no control point. One meter may be more sensitive to green, another to red, you can't use one to calibrate the other. You can try the sunny 16 rule with different colors, of course.. Are you shooting slide film, color neg, or silver B&W? If B&W, I'd just go out and shoot, take notes (mental or otherwise) and compensate the workflow. That means tweaking your metering / film ISO setting (same thing), your development times and agitation regimen. Use the data printed along the edge of the film as a control point for developing. If you are shooting slide film you have to be more careful with metering. Here's a story about metering and slide film: I visited the beach with a friend of mine one day, and we both shot this lighthouse: http://www.markcassino.com/newsite/portfolios/lighthouses/pages/0204l07.htm He had a Nikon F5 with a super sophisticated evaluative / color corrected metering system that he relied on. I had a Pz-1p. I spot metered off the black metal frame, did some quick zone calcs in my head, and set the exposure manually. We both shot ISO 100 slide film (him Provia, me E100S.) My shots came out very well - maybe 1/4 to 1/2 stop over exposed, but very usable. His were a mess. SO taking control of metering with film is important. Good luck! MCC On 5/21/2012 8:27 PM, Kenton Brede wrote: I'm making a foray into film and decided I should get a light meter. I bought a used Sekonic L-508 which has both incident and spot metering. Messing around with the K-5 and Sekonic, I found the readings didn't really match up. So I took a picture of the blue sky, the histogram was spiked in the center. I then spot metered the sky. I used the compensation function to dial in 3AV to bring the meter in line with the K-5's shutter, ISO and aperture. I used a gray card in the shade to meter off of with the K-5, and then matched those settings on the Sekonic by dialing in a -1AV for the incident reading. Does this sound like a decent calibration method? I went around metering things and taking shots with the K-5. I found that if I spot metered off a shaded green bush, I needed to speed up the shutter 2 stops to bring the histogram near center. When metering off a gray cloud, with silver lining, I sped up the shutter a couple stops to bring the histogram to center. The incident meter seemed to get the K-5 in the ballpark when metering in front of a tan shed, while the meter was facing the direction the sun. In shade, facing away from the sun, I generally had to slow the shutter down a couple stops. Does this sound like the way an accurate light meter works? I've never used one. Any thoughts appreciated. I realize all this hinges on the K-5 being accurate, and assuming the film cameras will work with the same meter readout as the K-5. I probably should have just purchased a new model, but good ones are expensive! Thanks, -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
RE: My light meter working OK?
From: Kenton Brede I'm making a foray into film and decided I should get a light meter. I bought a used Sekonic L-508 which has both incident and spot metering. Messing around with the K-5 and Sekonic, I found the readings didn't really match up. So I took a picture of the blue sky, the histogram was spiked in the center. I then spot metered the sky. I used the compensation function to dial in 3AV to bring the meter in line with the K-5's shutter, ISO and aperture. I used a gray card in the shade to meter off of with the K-5, and then matched those settings on the Sekonic by dialing in a -1AV for the incident reading. Does this sound like a decent calibration method? I went around metering things and taking shots with the K-5. I found that if I spot metered off a shaded green bush, I needed to speed up the shutter 2 stops to bring the histogram near center. When metering off a gray cloud, with silver lining, I sped up the shutter a couple stops to bring the histogram to center. The incident meter seemed to get the K-5 in the ballpark when metering in front of a tan shed, while the meter was facing the direction the sun. In shade, facing away from the sun, I generally had to slow the shutter down a couple stops. Does this sound like the way an accurate light meter works? I've never used one. Any thoughts appreciated. I realize all this hinges on the K-5 being accurate, and assuming the film cameras will work with the same meter readout as the K-5. I probably should have just purchased a new model, but good ones are expensive! Thanks, I'm a little confused by what you wrote above, but I have a Sekonic L-408 & it has an exposure compensation function that lets you permanently (until you choose to change it) set a compensation. I had to dial in a little bit of compensation to get it to match my K10D, and then change to a different compensation when I got the K20D. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
