Re: Re: [pinhole-discussion] exposure outdoors using meter
Thanks for that Guillermo, so as understand it it doesn't matter what the shutterspeed is for you meter reading its the f-stop that counts as it will be converted recipricly anyway. i was using paper for this exercise and thought that you set the shutter speed to the iso of the neg material used, and make a light reading from there. Thanks again for the info :) From: Guillermo pen...@home.com Date: Wed, 18 Jul 2001 08:23:39 -0400 To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] exposure outdoors using meter - Original Message - From: heys...@xtra.co.nz With your info i got off your website, the sunny16 + iso exposure rule, when using a meter do you use the meter reading and the iso=shutterspeed to calculate your exposure? Did you mean iso+shutterspeed? if so, here is the answer (BTW, I may overexplain, my excuses in advance for doing that): When I use a meter, I set it for the ISO of the emulsion in use, then I take a reading and obtain a pair of exposure values, f/stop+shutter_speed, that is. Then I translate that pair of exposure values to an equivalent pair for when the f/stop is the one of my pinhole camera. For instance: My pinhole camera is f/512, a meter reading gives me f/45 @ 1/30, there are 7 stops between f/45 and f/512 (45 - 64,90,128,180,256,360,512), therefore the equivalent pair of exposures values f/45@1/30 for my pinhole camera would be f/512 @ (1/30 +7stops). 1/30 +7 stops is equal to doubling the time 7 times 1/30 - 1/15, 1/8, 1/4, 1/2, 1, 2, 4secs, my pinhole camera exposure should then be f/512@4 seconds plus any reciprocity correction needed for the emulsion in use. I used it to teach a class but had varying results, although i have suspitions that the cameras were dodgy. I just need a little clarification on this. But the ones that did turn out on my camera and one other were as near perfect as i could have hoped. The only way to get consistent results from many cameras is if you have measured the pinholes of all the cameras in a relatively accurate way, which in turn allow you to know the f/stop of your cameras. Obviously, pinhole of all the cameras should be clean, free of burrs and obstructions. Also if you have any info on Pinhole under studio flash conditions i would really appretiate it, i had a formula worked out which worked well for my camera but had limited success with the others. I used exposure = difference of stops from meter reading to camera aperture x 1.5 If you have any suggestions to improve this, that would be great. Here is what the Laws of physics MANDATE: you should give a number of flash pops equal to 2 multiplied by itself a number of times equal to the difference of stops. For instance, stops of difference = 5, number of pops= 2x2x2x2x2 = 32 pops And then you will have to give few pops more to compensate for INTERMITTENCY (sp) EFFECT which for the above example would state: an exposure of 32 pops of low power flashes (flash-A) is less effective that one single pop of a flash-B with a power equal 5 times the power of flash-A. If shooting negative material, you may obtain printable results for up to 4 stops of difference when using your formula, but for the more stops of difference the more unlikely you will. Hope it helps, Guillermo ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
[pinhole-discussion] exposure outdoors using meter
Guillermo, With your info i got off your website, the sunny16 + iso exposure rule, when using a meter do you use the meter reading and the iso=shutterspeed to calculate your exposure? I used it to teach a class but had varying results, although i have suspitions that the cameras were dodgy. I just need a little clarification on this. But the ones that did turn out on my camera and one other were as near perfect as i could have hoped. Also if you have any info on Pinhole under studio flash conditions i would really appretiate it, i had a formula worked out which worked well for my camera but had limited success with the others. I used exposure = difference of stops from meter reading to camera aperture x 1.5 If you have any suggestions to improve this, that would be great. Thanks :)
Re: Re: [pinhole-discussion] pin hole and flash
I used this theory to start with, (the difference between f-stops = number of flashes) but i found it to be insufficient. i found that i got good results from multiplying the difference by 1.5. (So; exposure = the difference of meter reading and camera aperture x 1.5) EG; meter = f-64, camera = f-283 'pops' = 18. and also soft boxes are not good you need directed undiffused light this seems to work better. I have to run a workshop on my theories as part of my course so i will get back on the flash formula, and see if it accurate for more than just my camera. thanks for the replys, i'll check out the archives ;) From: William Erickson erick...@ic.mankato.mn.us Date: Thu, 5 Jul 2001 09:53:14 -0500 To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] pin hole and flash I used flash until I dropped the unit and broke the bulb. You need to meter the flash, obtain the f stop that will give good exposure with the flash placed where it is, then calculate how much smaller your aperture is than the aperture you obtained by metering, then flash it that many times. If the pinhole is 1/50 the area of the metered aperture, you will need to flash 50 times to get the same exposure. On the other hand, pinhole is about play, so just play with it. Try hoding the flash close to areas you want to emphasize, further fronm the shadow areas, and do trials tom see how many flashes you need. there's some abut flash in Eric Renners book also. From: Jarrard To: pinhole-discussion@p at ??? Sent: Thursday, July 05, 2001 3:51 AM Subject: [pinhole-discussion] pin hole and flash hello. Im a photography student in New Zealand, and i am using pinhole photography as a major part of my projects, together with alternative printing emultions like callitype etc. I have been working in the studio using flash and was wondering if anybody has used this technique and had much success, and if they have and tips they could share. i have not been able to find any info on using flash with a pinhole camera anywhere and was hopeing that someone had. Or if anyone is interested in my work with pinhole in the studio, i've had some pretty nice results, with a few of the images :) If anyone knows the best sites to go to for info and such, i would greatly appertiate it :) Thanks. I used flash until I dropped the unit = and broke the=20 bulb. You need to meter the flash, obtain the f stop that will give good = exposure with the flash placed where it is, then calculate how much = smaller your=20 aperture is than the apertureyou obtained by metering, then flash = it that=20 many times. If the pinhole is 1/50 the area of the metered aperture, you = will=20 need to flash 50 times to getthe same exposure. On the other hand, = pinhole=20 is about play, so just play with it. Try hoding the flash close to areas = you=20 want to emphasize, further fronm the shadow areas, and do trials tom see = how=20 many flashes you need.there's some abut flash in Eric Renners book = also. =20 From: Jarrard
