Hi, > PS: If your camera allowed you to set the aperture through the camera or the > aperture ring, don't be surprised if the chosen shutter speed differs a bit. > This is due to the rather "loose" manufacturing tolerance.
aren't you assuming the very point that's at question here? In other words, if your camera meter disagrees with the external meter, you're assuming that the camera meter is accurate and that the aperture or shutter are inaccurate. But the purpose of the exercise is to determine the accuracy of your meter, so you've made a circular argument and undermined everything else you wrote. --- Bob mailto:[EMAIL PROTECTED] Wednesday, July 10, 2002, 8:27:19 AM, you wrote: >>Can you explain in more detail? >>If I take a picture of a Kodak grey card in bright sunshine (say) and then >>compare the slide >>how do I know that I am not being fooled by the 'characteristics' of the >>film rather then exposure? >>I am sorry if this is obvious to you but it is not to me. >>I used to work on optical analytical equipment and perhaps I am thinking in >>to exact terms. >>With my cameras I just get to know the 'personality' of each >>and beat it around the head a bit until it does what I want ;-) >>I would like to be able to explain the procedure of 'calibrating' to my >>wife >>who is just getting into macro photography (MZ7 and either velvia or Kodak >>100 extra colour). >>Do you know of any links to articles about this? > My approach was rather simple. I have a Minolta IV F handheld meter which is > accurate up to 1/10EV (confirmed by the Minolta service centre). > 1) Place the Kodak card (the larger, the better) on a table. > 2) Light the card evenly, and the light source must be stable. (sunlight is > not a good choice because it varies every second even it appears perfectly > identical to human eyes). > 3) Place the light meter on different position of the grey card and take > some incident readings. If all reading are identical, the grey card will be > evenly lighted. > 4) Point the camera to the centre of the grey card to take some readings and > see if they match the incident readings from the handheld meter. This should > work for centre-weighted, spot & multi-segment meterings (since the grey > card was evenly lighted, the multi-segment metering should not do any > auto-adjustment itself, and would behave just like centre-weighted > metering). > PS: If your camera allowed you to set the aperture through the camera or the > aperture ring, don't be surprised if the chosen shutter speed differs a bit. > This is due to the rather "loose" manufacturing tolerance. > regards, > Alan Chan - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
