[...] > > 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.
