Re: [pinhole-discussion] Micro or macro photo with pinhole photo
- Original Message - From: Gregg Kemp gregg.kemp@??? Guillermo, I don't remember ever seeing your correction formula before. Is that theoretical, or have you tested it? Theoretical, Gregg, as I haven't done any close up work myself. For those (few) people interested in were that correction factor comes from, here it is: ** Pinhole is in most ways, not different than glass lens photography. The lens conjugate equation is: 1 / F = 1 / I + 1 / O where I = distance pinhole to Image plane; F = Focal length and O = distance pinhole to Object being photographed. We can simplify that to: F = I x O / I + O When the Object being photographed is at infinity ( O = infinity ): I + O = O therefore the formula F = I x O / I + O becomes: F = I x O / O and that becomes F = I In other words, when the Object is far away (more than 10 times the distance pinhole to film, in practical terms), the Focal length of the camera is equal to the distance pinhole to film plane. Now, when the Object being photographed is close to the pinhole lens (less than 10 times the distance pinhole to film, in practical terms), the Focal length of the camera is given by (as I stated above): F = I x O / I + O For close up work, then, F has to be substituted (in any of the formulas for optimum pinhole size) by: I x O / I + O For instance, the formula I use is: D = 0.0073 x SQRT( F ) where D = pinhole diameter in inches; F=pinhole camera focal length and SQRT stands for square root of For close up work that formula becomes: D = 0.0073 x SQRT( I x O / I + O ) As I said before, F = I for infinity, therefore I can write the infinity formula as D = 0.0073 x SQRT( I ) Base on that, I can also rewrite the close-up formula as: D = 0.0073 x SQRT( I ) x SQRT ( O / I + O ) There you have the correction factor: SQRT ( O / I + O ) BTW, there are many formulas for optimum pinhole size but all have within them SQRT(F), therefore, the above correction factor should apply fine to all of them. Let's see an example: Our pinhole camera has a distance pinhole to film I = 8 and the Object being photographed is O = 12 away from the pinhole, what size of pinhole is the optimum to use: The optimum pinhole size for infinity is: D = 0.0073 x SQRT ( 8 ) D = 0.020 (aprox) Correction factor is: SQRT ( 12 / 8 + 12 ) Correction factor is: 0.774 Pinhole size for close up work (object 12 from pinhole lens) D = 0.020 * 0.774 D = 0.0155 BTW, all the above is nothing but a sort of bellows correction. For people with mathfobia but that have read this msg up to this point, here are some corrections factor based on how many times the camera pinhole-film distance the object is away from the pinhole lens: less than 10 times = correction factor = 0.95 less than 9 times = correction factor = 0.94 less than 8 times = correction factor = 0.94 less than 7 times = correction factor = 0.93 less than 6 times = correction factor = 0.92 less than 5 times = correction factor = 0.91 less than 4 times = correction factor = 0.89 less than 3 times = correction factor = 0.86 less than 2 times = correction factor = 0.81 less than 1 times = correction factor = 0.70 less than 0.5 times = correction factor = 0.57 Another couple of formulas than may help the original's question poster are: Magnification M = I / O Therefore the Correction factor can also be written as: Correction factor = SQRT [ 1 / (M+1) ] So for instance, if she wanted to photograph an object 2 tall with a camera having 8 between pinhole and film and get a magnification of 2X, she will need to position the object at a distance: O = I / M = 8 / 2 = 4 O = 4 inches and the pinhole size (diameter) should be: D = 0.0073 SQRT(8) * SQRT[ 1 / (2+1)] D = 0.012 The image size will be 4 and therefore the minimum format size needed is 4x5 (portrait) or perhaps -better- 5x7 to allow for some cropping. Guillermo
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
At 05:26 PM 10/27/01 -0400, you wrote: For close up work just multiply your optimum pinhole size, obtained with any of the formulas available out there, by the correction factor: Correction factor = SQRT ( O / I + O ) where O = distance pinhole lens to object being photographed and I = distance pinhole lens to film SQRT stands for square root of Guillermo Guillermo, I don't remember ever seeing your correction formula before. Is that theoretical, or have you tested it? Gregg _ Pinhole Visions at http://www.??? Worldwide Pinhole Photograhy Day at http://www.pinholeday.org
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
- Original Message - From: Richard Heather rheat...@slonet.org See the pinhole size calculator at Pinhole Visions: (Larry Bullis) http://www.???/resources/articles/makingholes.php Guillermo's page: http://members.home.net/penate/pinsize.htm There are various calculations that are based on the assumption that you will shoot at infinity. For close up views a smaller hole will give sharper results. For close up work just multiply your optimum pinhole size, obtained with any of the formulas available out there, by the correction factor: Correction factor = SQRT ( O / I + O ) where O = distance pinhole lens to object being photographed and I = distance pinhole lens to film SQRT stands for square root of Guillermo
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
See the pinhole size calculator at Pinhole Visions: (Larry Bullis) http://www.???/resources/articles/makingholes.php Guillermo's page: http://members.home.net/penate/pinsize.htm There are various calculations that are based on the assumption that you will shoot at infinity. For close up views a smaller hole will give sharper results. Richard Heather luciana napchan wrote: Richard, What do you mean by the optimum size ? Thank you so much for all of you, it really helped me :-) From: Richard Heather Reply-To: pinhole-discussion@p at ??? To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Date: Fri, 26 Oct 2001 19:44:45 -0700 Use as large a negative as possible. 8x10 11x14 paper. Use a pinhole smaller than the optimum ( for infinity) size. Richard Heather luciana napchan wrote: Thank you for your response But I did not want a wide angle image, so for instance, if I want to make images of fruits, with a 6X9 120mm film, is my image going to be distorces ? How can I have a normal image for a 120mm film ? I do have a zero 6x9 camera and thinking to built a 4X5 one Thank you so much Luciana
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
That it is... I want to do closeups with a short sharpness area . So you want a small depth of field? You're out of luck with pinhole. Everything will be equally sharp... or unsharp.
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
Use as large a negative as possible. 8x10 11x14 paper. Use a pinhole smaller than the optimum ( for infinity) size. Richard Heather luciana napchan wrote: Thank you for your response But I did not want a wide angle image, so for instance, if I want to make images of fruits, with a 6X9 120mm film, is my image going to be distorces ? How can I have a normal image for a 120mm film ? I do have a zero 6x9 camera and thinking to built a 4X5 one Thank you so much Luciana
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
Maybe you're asking something else, like what is the normal lens for 6x9 film. I think it would be the same length as a diagonal from one corner of your film to the other. So, to calculate that you would take the square root of (6x6 + 9x9) which is approximately 11cm or 110mm. I think thats right. - Original Message - From: luciana napchan To: pinhole-discussion@p at ??? Sent: Friday, October 26, 2001 9:52 AM Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Thank you for your response But I did not want a wide angle image, so for instance, if I want to make images of fruits, with a 6X9 120mm film, is my image going to be distorces ? How can I have a normal image for a 120mm film ? I do have a zero 6x9 camera and thinking to built a 4X5 one Thank you so much Luciana From: George L Smyth Reply-To: pinhole-discussion@p at ??? To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Date: Fri, 26 Oct 2001 09:36:25 -0700 (PDT) --- luciana napchan wrote: -- I would like to know which camera should I use to make macro or micro photography with pinhole ? It doesn't matter - just place your subject close to the pinhole. Cheers - george = Handmade Photographic Images http://members.home.net/hmpi/ __ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ -- Get your FREE download of MSN Explorer at http://explorer.msn.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
Ah, so you want a longer focal length so you minimize the distortion from mapping the image onto a flat surface? You will only get a wide angle image if you use a short focal length. If you use a longer focal length, the distortion will be less as the area you are shooting will more approximate a flat surface. But you can still put the subject as close as you want to the lens. Anyone jump in a correct me. I'm just getting back into this myself. The other thing is, just try it and see what you get (I hate it when people tell me that). Dwight - Original Message - From: luciana napchan To: pinhole-discussion@p at ??? Sent: Friday, October 26, 2001 9:52 AM Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Thank you for your response But I did not want a wide angle image, so for instance, if I want to make images of fruits, with a 6X9 120mm film, is my image going to be distorces ? How can I have a normal image for a 120mm film ? I do have a zero 6x9 camera and thinking to built a 4X5 one Thank you so much Luciana From: George L Smyth Reply-To: pinhole-discussion@p at ??? To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Date: Fri, 26 Oct 2001 09:36:25 -0700 (PDT) --- luciana napchan wrote: -- I would like to know which camera should I use to make macro or micro photography with pinhole ? It doesn't matter - just place your subject close to the pinhole. Cheers - george = Handmade Photographic Images http://members.home.net/hmpi/ __ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ -- Get your FREE download of MSN Explorer at http://explorer.msn.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
Thank you for your response But I did not want a wide angle image, so for instance, if I want to make images of fruits, with a 6X9 120mm film, is my image going to be distorces ? How can I have a normalimage for a 120mm film ? I do have a zero 6x9 camera and thinking to built a 4X5 one Thank you so much Luciana From: George L Smyth <glsm...@yahoo.com> Reply-To: pinhole-discussion@p at ??? To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] Micro or macro photo with pinhole photo Date: Fri, 26 Oct 2001 09:36:25 -0700 (PDT) --- luciana napchan <lunapc...@hotmail.com>wrote: I would like to know which camera should I use to make macro or microphotography with pinhole ? It doesn't matter - just place your subject close to the pinhole. Cheers - george = Handmade Photographic Images http://members.home.net/hmpi/ __ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/ Get your FREE download of MSN Explorer at http://explorer.msn.com
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
--- luciana napchan lunapc...@hotmail.com wrote: HR htmldiv style='background-color:'DIV PBRI would like to know which camera should I use to make macro or micronbsp;photography with pinhole ?/P It doesn't matter - just place your subject close to the pinhole. Cheers - george = Handmade Photographic Images http://members.home.net/hmpi/ __ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com
