Re: [pinhole-discussion] f64,f90,f128?...
Andrew, f/stops progress by a factor of 1.414 which is the square root of 2, therefore, the numerical value of f/stops double every other stop. If we start at f/11 (we could have started with any f/stop), the next one is f/16, since they double every other stop, the progression would go like this: 1 (half 2) 1.4 (half 2.8 2 (half 4) 2.8 (half 5.6) 4 (half 8) 5.6 (half 11 or so!!) 8 (half 16) 11 --known starting consecutive f/stops 16 --known starting consecutive f/stops 22 (double 11) 32 (double 16) 45 (double 22...or so!!) 64 (double 32) 90 (double 45) 128 (double 64) 180 (double 90) 256 (double 128) .add infinitum So, if you know 2 consecutive full f/stops values, you can find out any other full f/stop in the progression. Guillermo - Original Message - From: Andrew Amundsen a...@tcinternet.net Can anyone help? What's the proper progression of f-stops above f90? Is f128 next and tell a couple more if you have the info at your fingertips. I've picked up a Finney Pinhole Bodycap for my Leica M. It's listed as a 30mm, approx. f128 and my Minolta meter goes to f90. So is f128 the next f-stop in the natural progression of reciprocity? Twice as small? If not someone please correct me! Thanks for the help, Andrew Amundsen
Re: [pinhole-discussion] 35 mm pinhole camera
Hi Zami, I have an old Yashica XYZ, I don't really remember the specs, but I found an adapter to use pentax thread lenses with it (it transforms the bayonet into a thread). I had some aluminum tubes made to fit this thread, so now it is easy to change focal distances and/or transform from Zone Plate to pinhole in no time. I even made a 300 mm plastic lens with an old pentax extension bellows, the aluminum tube and some black tape and it is working pretty well. Cheers Joao Zami Schwartzman wrote: Anyone has tried converting a 35 mm camera to pinhole ? I have modified an old Pentax Spotmatics Reflex camera , the idea was that using a 35 mm format will make it easier to experiment with various types of films . film drive , sutter timing , tripod attachement and release cable are already there and any local photo shop will process the films for me . I turned a lens boby on my lath that allows the metal foil be located 28 mm from the film . I discovered that with this camera I can flip the mirror up permanently without disabling other camera functions ( except for the viewfinder that obviously is shut off ) I use 0.02 mm copper foil .The pinhole was made under a x70 stereo microscope by using a very sharp pin ( honed under the microscope ) on hard back surface . the buurs on the oposit side had to be very carefuly treated with no. 400 sandpaper to get a perfect hole . Although not a sraight forward job , I can get perfect holes as small as 0.05 mm diameter ( I have scale on the microscope ) . there is no chance to get any smaller with manual pin puncturing tecniques . I experimented with a 0.1 mm hole , got some good close up pictures well exposed with Kodak gold 400 ASA( using f: 120 on the light meter ) but the results are quite out of focus on 10x15 prints . I wander if going further to a 0.05 hole will worth the panelty in the f number . Is there an optimun hole size for best sharpness ? or is it the smaller the better . I hear that some people are converting plastic 35 mm cameras , I wander what holes they use and how sharp is the resultant image they get . Zami -Original Message- From: pinhole-discussion-admin@p at ??? [mailto:pinhole-discussion-admin@p at ???]On Behalf Of DAVID WALTERS Sent: Friday, October 11, 2002 11:29 AM To: pinhole-discussion@p at ??? Subject: [pinhole-discussion] Re: New to the list and saying hello Evening, I apologize for the lag time on answering but I had a brief episode of file overload while trying to upload some pics (Sorry and thanks, Gregg). I have a pinhole from my last roll posted at http://photos.yahoo.com/bc/wal...@prodigy.net/lst?.dir=/Photo+art.src=ph;. order=.view=t.done=http%3a//photos.yahoo.com/ (badge), along with some other pieces of mine. The body cap is on my Canon EOS, I measured the distance at 49 mm and I'm using a laser drilled opening of .0102, this gives an f/stop of 163, I reckon. Using the bulb setting has given me fairly good results with Kodak film, although it seems to be able to meter through the pinhole. The Polaroid pinholes are from a Polaroid 210 with a hand drilled pinhole, I had such a bad rolloff because of reciprocity that I have stuck with B/W since. I might go back to color with the 210 and stick to extreme sun in the future, we'll see. Thanks for the welcome, David Walters ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] 35 mm pinhole camera
- Original Message - From: Zami Schwartzman zami...@netvision.net.il the buurs on the oposit side had to be very carefuly treated with no. 400 sandpaper to get a perfect hole . Although not a sraight forward job , I can get perfect holes as small as 0.05 mm diameter FYI, such small pinhole would be optimum for a camera with a 1.85mm focal length!! A bit impractical, if you ask me!! I experimented with a 0.1 mm hole , got some good close up pictures well exposed with Kodak gold 400 ASA( using f: 120 on the light meter ) but the results are quite out of focus on 10x15 prints . -Your f/stop should be f/280 and not f/120. -f/stop is given by dividing the focal length by the pinhole diameter (28/0.1 = 280) -As pointed out by erick...@hickorytech.net, you should be using a pinhole 0.00784 which is equivalent to 0.2mm. The 0.1mm pinhole is producing too much diffraction. -If you want relatively sharp 10x15 size results, I would suggest you shoot medium format or larger. I wander if going further to a 0.05 hole will worth the panelty in the f number . Only if you could mount that pinhole about 2mm from the film plane. The resulting image, BTW, would be a circular image no bigger than some 10mm in diameter. Is there an optimun hole size for best sharpness ? or is it the smaller the better. Take a look to this http://members.rogers.com/penate/pinsize.htm Guillermo
Re: [pinhole-discussion] 35 mm pinhole camera
Yes, there is a pinhole diameter that will give best sharpness for each distance from pinhole to film. The simplest version of the formula is (distance to film in inches)(55) equals the square of the optimal diameter in thousandths of an inch. In your case (1.12 inches)(55) equals 68.99, the square root of which is 7.84 thousandths, or 0.00784 inches.- Original Message - From: Zami Schwartzman zami...@netvision.net.il To: pinhole-discussion@p at ??? Sent: Saturday, October 12, 2002 2:28 AM Subject: [pinhole-discussion] 35 mm pinhole camera Anyone has tried converting a 35 mm camera to pinhole ? I have modified an old Pentax Spotmatics Reflex camera , the idea was that using a 35 mm format will make it easier to experiment with various types of films . film drive , sutter timing , tripod attachement and release cable are already there and any local photo shop will process the films for me . I turned a lens boby on my lath that allows the metal foil be located 28 mm from the film . I discovered that with this camera I can flip the mirror up permanently without disabling other camera functions ( except for the viewfinder that obviously is shut off ) I use 0.02 mm copper foil .The pinhole was made under a x70 stereo microscope by using a very sharp pin ( honed under the microscope ) on hard back surface . the buurs on the oposit side had to be very carefuly treated with no. 400 sandpaper to get a perfect hole . Although not a sraight forward job , I can get perfect holes as small as 0.05 mm diameter ( I have scale on the microscope ) . there is no chance to get any smaller with manual pin puncturing tecniques . I experimented with a 0.1 mm hole , got some good close up pictures well exposed with Kodak gold 400 ASA( using f: 120 on the light meter ) but the results are quite out of focus on 10x15 prints . I wander if going further to a 0.05 hole will worth the panelty in the f number . Is there an optimun hole size for best sharpness ? or is it the smaller the better . I hear that some people are converting plastic 35 mm cameras , I wander what holes they use and how sharp is the resultant image they get . Zami -Original Message- From: pinhole-discussion-admin@p at ??? [mailto:pinhole-discussion-admin@p at ???]On Behalf Of DAVID WALTERS Sent: Friday, October 11, 2002 11:29 AM To: pinhole-discussion@p at ??? Subject: [pinhole-discussion] Re: New to the list and saying hello Evening, I apologize for the lag time on answering but I had a brief episode of file overload while trying to upload some pics (Sorry and thanks, Gregg). I have a pinhole from my last roll posted at http://photos.yahoo.com/bc/wal...@prodigy.net/lst?.dir=/Photo+art.src=ph;. order=.view=t.done=http%3a//photos.yahoo.com/ (badge), along with some other pieces of mine. The body cap is on my Canon EOS, I measured the distance at 49 mm and I'm using a laser drilled opening of .0102, this gives an f/stop of 163, I reckon. Using the bulb setting has given me fairly good results with Kodak film, although it seems to be able to meter through the pinhole. The Polaroid pinholes are from a Polaroid 210 with a hand drilled pinhole, I had such a bad rolloff because of reciprocity that I have stuck with B/W since. I might go back to color with the 210 and stick to extreme sun in the future, we'll see. Thanks for the welcome, David Walters ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
[pinhole-discussion] 35 mm pinhole camera
Anyone has tried converting a 35 mm camera to pinhole ? I have modified an old Pentax Spotmatics Reflex camera , the idea was that using a 35 mm format will make it easier to experiment with various types of films . film drive , sutter timing , tripod attachement and release cable are already there and any local photo shop will process the films for me . I turned a lens boby on my lath that allows the metal foil be located 28 mm from the film . I discovered that with this camera I can flip the mirror up permanently without disabling other camera functions ( except for the viewfinder that obviously is shut off ) I use 0.02 mm copper foil .The pinhole was made under a x70 stereo microscope by using a very sharp pin ( honed under the microscope ) on hard back surface . the buurs on the oposit side had to be very carefuly treated with no. 400 sandpaper to get a perfect hole . Although not a sraight forward job , I can get perfect holes as small as 0.05 mm diameter ( I have scale on the microscope ) . there is no chance to get any smaller with manual pin puncturing tecniques . I experimented with a 0.1 mm hole , got some good close up pictures well exposed with Kodak gold 400 ASA( using f: 120 on the light meter ) but the results are quite out of focus on 10x15 prints . I wander if going further to a 0.05 hole will worth the panelty in the f number . Is there an optimun hole size for best sharpness ? or is it the smaller the better . I hear that some people are converting plastic 35 mm cameras , I wander what holes they use and how sharp is the resultant image they get . Zami -Original Message- From: pinhole-discussion-admin@p at ??? [mailto:pinhole-discussion-admin@p at ???]On Behalf Of DAVID WALTERS Sent: Friday, October 11, 2002 11:29 AM To: pinhole-discussion@p at ??? Subject: [pinhole-discussion] Re: New to the list and saying hello Evening, I apologize for the lag time on answering but I had a brief episode of file overload while trying to upload some pics (Sorry and thanks, Gregg). I have a pinhole from my last roll posted at http://photos.yahoo.com/bc/wal...@prodigy.net/lst?.dir=/Photo+art.src=ph;. order=.view=t.done=http%3a//photos.yahoo.com/ (badge), along with some other pieces of mine. The body cap is on my Canon EOS, I measured the distance at 49 mm and I'm using a laser drilled opening of .0102, this gives an f/stop of 163, I reckon. Using the bulb setting has given me fairly good results with Kodak film, although it seems to be able to meter through the pinhole. The Polaroid pinholes are from a Polaroid 210 with a hand drilled pinhole, I had such a bad rolloff because of reciprocity that I have stuck with B/W since. I might go back to color with the 210 and stick to extreme sun in the future, we'll see. Thanks for the welcome, David Walters ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
