Re: [pinhole-discussion] Sally Mann
I appreciate your info on the Ambrotypes and I appreciate the article info too I have been fascinated about these images of hers since I first saw them... Wendy Wendy Garfinkel Garfinkel Design 185 Shadow Moss Drive Athens, GA 30605-3467 === phone: (706) 369-6831 fax: (706) 369-1761
Re: [pinhole-discussion] Zone Plate Focus stringency
I think technically they should be refocused (anyone, please correct me if I'm wrong).but in practical terms my experience is, they needn't be. Try simply setting it to it's designed focal length and shootingIMHO little out of focus softness is often a plus. Mike In a message dated 10/28/01 5:02:21 PM, tsh...@silver-bayou.com writes: Once you have the zone plate focused for one object, will it be focused for any other objects closer or further away, or do I need to refocus according to the distance of my subject? dwight
[pinhole-discussion] Enlarger bellows on handbuilt camera
It seems like I read somewhere that an enlarger bellows is not robust enough to keep out sunlight if used on a camera. I've got an old 4x5 enlarger that I'm considering copping the bellows off of to build a camera. Anyone know anything about this? Dwight
Re: [pinhole-discussion] New very slow film
Wow, that is an interesting film. The 1000x enlargement was quite impressive. You can see the hands on the watch of a lady sitting far away, on top of a building!. John - Original Message - From: Jean Daubas j.dau...@free.fr To: pinhole-discussion@p at ??? Sent: Saturday, October 27, 2001 3:41 PM Subject: [pinhole-discussion] New very slow film Hi all ! I know that among our lensless community, we are numerous to have a strong sympathy for slow or ultra-slow films which, combined with the specificities of pinhole photography, allow us to experiment new dimensions of time, duration,etc. Unfortunately, slow films are not so numerous and we just lost one of them : Agfapan 25, since Agfa officially announced its definitive discontinuation. I really loved it and was not far from thinking that it was the best film ... And now arrives a completely new product which seems to have astonishing characteristics : Gigabit film. I suggest you to have a look at http://www.gigabitfilm.de/ where you will find all info about this astonishing product (some pages or translated in English, I believe). And if you want to try it, you will find the address of the different importers for various countries. I have not yet tried it but hope to do it soon. Film is sold with its developer and it seems to me very, very expensive... But it seems that the quality of the film is worth a good try ! Hope it helps, cheers from France Jean ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] New very slow film
Jean, Is Agfa discontinuing all it's films including Agfapan 100 and 400? In a message dated 10/27/01 6:00:17 PM, j.dau...@free.fr writes: Unfortunately, slow films are not so numerous and we just lost one of them : Agfapan 25, since Agfa officially announced its definitive discontinuation. I really loved it and was not far from thinking that it was the best film
Re: [pinhole-discussion] Vera Lutter
Dear All, The talk by Vera Lutter at the Minneapolis College of Art and Design is actually on Thursday, November 29 at 7:00 pm. I apologize for any confusion my confusion has caused. (The November 15 presenter is Paul Shambroom, a wonderful lens photographer. www.paulshambroomart.com ) Tom - Original Message - From: Tom Miller twmil...@mr.net To: pinhole-discussion@p at ??? Sent: Wednesday, October 24, 2001 5:22 PM Subject: [pinhole-discussion] Vera Lutter Dear Everyone, Is anyone familiar with Vera Lutter and her pinhole work? She will be giving a talk at the Minneapolis College of Art and Design on Thursday evening, November 15. Apparently, she makes room-sized pinhole images of factories, etc. Sounds intriquing. Tom ___ 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
- 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] Ilfochrome
In a message dated 10/27/01 6:38:22 PM, erick...@hickorytech.net writes: I can't seem to find the processing chemicals for ilfochrome in any sort of volumes practical for 'wet lab' home processing. It looks like the chemicals are only packaged in larger quantities designed for roller processers. Anybody with more information? I have a package of 2 one litre bottles (little plastic jars, A, B and C) of Ilfochrome chemistry that I purchased from B H some time ago...maybe a year or so. I would guess they still have it but not sure about the shipping issue. Let me know if you want me to give them a call to find out if they ship towhere are you? leezy
