Re: [pinhole-discussion] pinhole size
Michael, Pinholes are afocal, meaning: they don't have focal length, per se. You can use them to whatever distance pinhole-film you wish, knowing that if you don't use them to their optimum distance, results will be less-sharp, which depending on the photographer intentions could be good or bad for your resulting image. Knowing that a pinhole can be used at any distance, again, they are afocal, the fall-off is not caused by its size, but by 3 different factors: first: light on the film plane decreases as the distance pinhole-film increases, distance at the center is shorter than distance at the edges of the film, therefore you'll have fall-off as you go off film center. secondly: seen from the center of the film the pinhole looks round (assuming you made it round), but seen from the edges, it would look oval, that translate into less area for light to go thru, that too causes fall-off. Lastly: light falling at the edges, falls at an angle on the film, therefore covers a bigger area of the film, that too, causes fall off. Geekly speaking :) the fall off at the edges will be a factor of the function COSINE to the 4th power of half the total angle of view of your camera, in your case that translate to just over 3 stops. BTW, glass lenses are not exempt of this COSINE^4 condition, that is why for wide angle lenses manufacturers also make special filters to go with them and that correct the fall off at the edges by causing fall off at the center (forgot their name, center filters I think). If you were to use a pinhole optimum for 73mm, your fall off will be the same, the fall off is only a function of the angle of view, in other words, the wider the angle of your camera, the more fall off. Your camera has 109 degrees angle of view, the format diagonal is just 2.8 times the distance pinhole-film, BTW. Optimum does not mean longest, it means if you want the sharpest images possible use this distance, longer or shorter that optimum and the resolution suffers. The only way to get less fall-off is to make the film or paper to conform to a cylindrical shaped film plane and position the pinhole at the center of the circle describing the half cylinder, there are some examples here: http://www.cyberbeach.net/~dbardell/pinhole.html The reason why such cameras have less fall off is that the distance pinhole-film is the same from center to edge of film and also the light always falls perpendicular to the film so it doesn't have to cover more area (as explained above). Something else that contributes to a fall-off is the thickness of the material the pinhole is made of and whether it has burrs around its edges. Guillermo - Original Message - From: Michael Healy mjhe...@kcnet.com I bought the 12-lens set from Pinhole Resourses, and I've been using the .0102/.259mm pinhole on my 4x5. This one's claimed optimal focal length is supposed to be 48mm. I am using it with a recessed lensboard to a length of about 50mm. That's the closest I can get even w/ a bag bellows. The results are fantastic. I love the focal length. Unfortunately, its fall-off is quite noticable. No vignetting, but the fall-off is about 1.5-2 stops from center to edge. So I think I have to try the next one of the bunch, the one whose optimal focal length is reported to be 73mm. That seems like quite a jump, though. Before I try this at a shorter bellows length than 73mm, has anybody done this? Will I have problems just shooting this at, say, my 50mm (w/ bellows compensation)? Does their optimal mean longest? That's what the 48mm seems to mean, that if you go even to 50mm, you'll have fall-off. Anybody w/ experience of this? If this works, should I consider ordering a 50-55mm pinhole to fit my 4x5? I really like the weird, extreme result from the short one -- it's just that the light fall-off makes cyanotypes very difficult to print. I'm anticipating that albumen won't work much better. Thoughts? Mike Healy
[pinhole-discussion] pinhole size
I bought the 12-lens set from Pinhole Resourses, and I've been using the .0102/.259mm pinhole on my 4x5. This one's claimed optimal focal length is supposed to be 48mm. I am using it with a recessed lensboard to a length of about 50mm. That's the closest I can get even w/ a bag bellows. The results are fantastic. I love the focal length. Unfortunately, its fall-off is quite noticable. No vignetting, but the fall-off is about 1.5-2 stops from center to edge. So I think I have to try the next one of the bunch, the one whose optimal focal length is reported to be 73mm. That seems like quite a jump, though. Before I try this at a shorter bellows length than 73mm, has anybody done this? Will I have problems just shooting this at, say, my 50mm (w/ bellows compensation)? Does their optimal mean longest? That's what the 48mm seems to mean, that if you go even to 50mm, you'll have fall-off. Anybody w/ experience of this? If this works, should I consider ordering a 50-55mm pinhole to fit my 4x5? I really like the weird, extreme result from the short one -- it's just that the light fall-off makes cyanotypes very difficult to print. I'm anticipating that albumen won't work much better. Thoughts? Mike Healy
Re: [pinhole-discussion] pinhole size
Achal, Hello I. Zarkov! (it is Igor?) Call me Ishmael... Thanks for the links, will explore further. :-] = Z _ Send and receive Hotmail on your mobile device: http://mobile.msn.com
Re: [pinhole-discussion] pinhole size
Hello I. Zarkov! (it is Igor?) The use of EM grids is not my idea. I got fascinated with it after visiting Chris Patton's pinhole pages. And, since he is from the same institute as I am, initially I thought, he is from the same campus and started communication with him about using the grids, so idea is his. I am attaching a link below about the purchase and price. I don't have any more grids, I got few from Chris and they are installed on my brass plates already. I am using 100uM grid (actually, it is not a grid, it is a single circular hole, as against to our usual 'grid' grids of EM). I tried 75uM that Chris sent me and it was creating too much diffusion (~6 Inch focal length body). I had pasted the link before but here is my link using this grid again along with purchase links: thanks, achal http://photos.yahoo.com/achalpashine (click on pinhole day) http://www.stanford.edu/~cpatton/ems.htm http://www.emsdiasum.com/ems/grids/gilder.html Achal Pashine Pediatric Immunology Center for Clinical Sciences Research, Room 2120 269 Campus Drive Stanford, CA 94305-5164 Tel: 1-650-498-7574 FAX: 1-650-498-6077 - Original Message - From: I Zarkov dr_izar...@hotmail.com To: pinhole-discussion@p at ??? Sent: Wednesday, July 24, 2002 5:37 AM Subject: Re: [pinhole-discussion] pinhole size Achal, How big is the size of the openings within the grids? As I remember from years ago the size may be variable depending on the slot types of EM grids. I imagine that you're using apertures of less than 500 nm. Or do I misunderstand you and you use the whole circular grid as the pinhole lens? Thanks I. Zarkov (former EM tech) _ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx ___ 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] pinhole size
Scan the pinhole on a flatbed scanner with known scale and then print the scan and figure out the ratio of printsize of known scale to actual size and then determine the size of a pinhole based on this conversion factor. BTW, I have microscopes too, since I work in a life science lab. Incidentally, as I wrote long time ago, I have been using electron microscope grids as pinholes, you don't have to measure the size, you just buy them and they are perfect and quality controlled; besides, they are cheap, you get 100s in ~$10.00! :) achal Achal Pashine Pediatric Immunology Center for Clinical Sciences Research, Room 2120 269 Campus Drive Stanford, CA 94305-5164 Tel: 1-650-498-7574 FAX: 1-650-498-6077 - Original Message - From: Jean Hanson jhan...@pon.net To: pinhole-discussion@p at ??? Sent: Sunday, July 21, 2002 3:53 PM Subject: [pinhole-discussion] pinhole size I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean ___ 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] pinhole size
I use Guillermo's method. It's a lot easier than it sounds. :) From: G.Penate pen...@rogers.com Reply-To: pinhole-discussion@p at ??? Date: Mon, 22 Jul 2002 19:34:30 -0400 To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] pinhole size - Original Message - From: Jean Hanson jhan...@pon.net I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean Risking being redundant with some of the many good suggestions you have received so far, I'd like to point you to a small article I wrote on that topic: http://members.rogers.com/penate/diameter.htm Guillermo ___ 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] pinhole size
- Original Message - From: Jean Hanson jhan...@pon.net I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean Risking being redundant with some of the many good suggestions you have received so far, I'd like to point you to a small article I wrote on that topic: http://members.rogers.com/penate/diameter.htm Guillermo
Re: [pinhole-discussion] pinhole size
Hello jean, I do it this way, works fine: I cut a stroke of paper, 10 mm wide, 3 or 4 cm long, and place it in a transparancy slide frame. In another slide frame I place the metal with the pinhole. Put the first frame in a slide projector and enlarge it a lot, i.e. till the 10 mm stroke measures 200 mm: an enlargement of 20. Measure the size of the pinhole at the same enlargement and you have a very good idea of the size of the pinhole. Good luck Hennie Koenen - Original Message - From: Jean Hanson jhan...@pon.net To: pinhole-discussion@p at ??? Sent: Monday, July 22, 2002 12:53 AM Subject: [pinhole-discussion] pinhole size I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean ___ 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] pinhole size
The simpler way is just to scan it. -Original Message- From: Jean Hanson [mailto:jhan...@pon.net] Sent: Domingo, 21 de Julho de 2002 23:53 To: pinhole-discussion@p at ??? Subject: [pinhole-discussion] pinhole size I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean ___ 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] pinhole size
One simple way is to photograph the pinhole over a light box with a ruler beside it, then enlarge the negative as big as you can and compare the diamter of.the aperture with distance on the ruler. Comparators for threads are said to work fairly well. I bought a set of pre-drilled pinholes and use them for eyeball comparison. - Original Message - From: Jean Hanson jhan...@pon.net To: pinhole-discussion@p at ??? Sent: Sunday, July 21, 2002 5:53 PM Subject: [pinhole-discussion] pinhole size I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean ___ 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] pinhole size
I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean
Re: [pinhole-discussion] pinhole size
Measure the distance from the pinhole to the back. Multiply the distance (in inches) by 55. The result is the square of the optimal diameter, in thousandths of an inch. If an altoid can is 3/4 of an inch deep, the optimal diamter is .0064 inches. - Original Message - From: Steve Shapiro sgsh...@redshift.com To: pinhole-discussion@p at ??? Sent: Friday, July 19, 2002 4:07 PM Subject: Re: [pinhole-discussion] pinhole size I never got a definitive answer to my questioon about the best advisable pinhole size for the sharp image with an Altoid can pinhole camera. S - Original Message - From: William Erickson erick...@hickorytech.net To: ppinhole discussion pinhole-discussion@p at ??? Sent: Friday, July 19, 2002 1:52 PM Subject: [pinhole-discussion] pinhole size I misspoke this morning when i sent a comment about the relationship between pinhole size and sharpness. I indicted that exposure doubles with every 40% increase in diamter. It should have been the area of the aperture doubles, and thus time halves. ___ 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] pinhole size
There have been several optimum size formulas over the last century but this one works fine if you're after maximum sharpness the pinhole can afford. square root of (0.0016 x focal length) Of course, focal length refers to the planned distance between the pinhole and film in your camera/tin. Mike In a message dated 7/19/02 5:08:12 PM, sgsh...@redshift.com writes: I never got a definitive answer to my questioon about the best advisable pinhole size for the sharp image with an Altoid can pinhole camera. S
[pinhole-discussion] pinhole size
I misspoke this morning when i sent a comment about the relationship between pinhole size and sharpness. I indicted that exposure doubles with every 40% increase in diamter. It should have been the area of the aperture doubles, and thus time halves.
[pinhole-discussion] pinhole size and sharpness.
I am attempting to recover from a deep seated addiction to commercially drilled pinholes. My research yields the following, which I will share because I have never seen it written anywhere before. Exposure time for any given pinhole doubles with each 40% increase in diameter, but sharpness of image with changes in pinhole diameter degrades much more slowly, and requires quite drastic increases in pinhole diameter to give significant changes in sharpness. I've done some testing to confirm this, but the best example of this is on page 128 of Eric Renner's book. You can see some increased softness of the image with a pinhole twice as wide as optimal, but you really don't begin to lose detail until the pinhole is between three and four times as wide as optimal. Even a pinhole ten times as wide as optimal will yiled a very readable image. In Eric's example pick an arbitrary focal length and divide the various fstops shown in the illustration into it. You will see the ratios of aperture diameter associated with different degrees of sharpness. Thus the error associated with using one size needle or another, over a wide range of focal lengths, is negligable (sp?). One will get surprisingly uniform sharpness and clarity of the image with any pinhole, because the difference in pin diameters for different numbers of needle is far less than 100%. Many of you have taken this for granted but here is a way for the precision technonerds to see a way to loose their chains.
Re: [pinhole-discussion] Pinhole size for a Nikon bodycap
calculate the optimal diameter for 38 mm distance. - Original Message - From: LEGE ARTIS legear...@trak.to To: pinhole-discussion@p at ??? Sent: Sunday, October 07, 2001 11:43 AM Subject: [pinhole-discussion] Pinhole size for a Nikon bodycap Hi there, Does anybody know which size the pinhole should be on a Nikon bodycap. I am trying to make one on my own. Hans ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ Free WebTools for Webmasters! http://www.bravenet.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] Pinhole size for a Nikon bodycap
Hi Hans , I often use a Pinhole Body Cap on my old Nikon FE body or sometimes on a Nikon F801 because it allows me to have both lens and pinhole camera when I can bring with me only minimum weight of photo equipment... I had bought 2 years ago a Finney pinhole body cap which I ordered at Pinhole Resource. It is sold with the following data : f/ 180 @ 50 mm Diameter :.011, which makes something between 0,27 and 0,28 mm I think . The results are really very pleasant ! Hope it helps Cheers from France Jean - Original Message - From: Markus Birsfelder b...@active.ch To: pinhole-discussion@p at ??? Sent: Sunday, October 07, 2001 7:43 PM Subject: AW: [pinhole-discussion] Pinhole size for a Nikon bodycap Hans Since the distance between the hole and the film support at the back of the camera is approx. 5mm, to get the best possible sharpness the pinhole should be 0.25 mm. However, part of the charme of pinhole photos is a slight fuzzyness combined with the fact that it does not matter wether objects are very close or very distant. Perhaps you would want to use pinholes of 0.3 mm or even larger. Regards Markus Hi there, Does anybody know which size the pinhole should be on a Nikon bodycap. I am trying to make one on my own. Hans ___
AW: [pinhole-discussion] Pinhole size for a Nikon bodycap
Hans Since the distance between the hole and the film support at the back of the camera is approx. 5mm, to get the best possible sharpness the pinhole should be 0.25 mm. However, part of the charme of pinhole photos is a slight fuzzyness combined with the fact that it does not matter wether objects are very close or very distant. Perhaps you would want to use pinholes of 0.3 mm or even larger. Regards Markus -Ursprüngliche Nachricht- Von: pinhole-discussion-admin@p at ??? [mailto:pinhole-discussion-admin@p at ???]Im Auftrag von LEGE ARTIS Gesendet: Sonntag, 7. Oktober 2001 18:43 An: pinhole-discussion@p at ??? Betreff: [pinhole-discussion] Pinhole size for a Nikon bodycap Hi there, Does anybody know which size the pinhole should be on a Nikon bodycap. I am trying to make one on my own. Hans ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ Free WebTools for Webmasters! http://www.bravenet.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
[pinhole-discussion] Pinhole size for a Nikon bodycap
Hi there, Does anybody know which size the pinhole should be on a Nikon bodycap. I am trying to make one on my own. Hans ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ Free WebTools for Webmasters! http://www.bravenet.com
