Re: [pinhole-discussion] zone plate
- Original Message - From: tatico...@starmedia.com Hello all! I'm brazilian and I have just started to try pinhole and I can't understand what is zone plate,I've read about this in English but I didn't understand what's this! Can anybody help me?! Thanks Check Joao Riveiro's article written in Portuguese: http://www.alaz.f2s.com/tec/tec1.html Guillermo
[pinhole-discussion] zone plate
Hello all! I'm brazilian and I have just started to try pinhole and I can't understand what is zone plate,I've read about this in English but I didn't understand what's this! Can anybody help me?! Thanks -- Abra grátis sua conta no StarMedia Email. Inscreva-se agora mesmo! http://www.br.starmedia.com --
[pinhole-discussion] Re: Pinhole-Discussion digest, Vol 1 #409 - 14 msgs
Guillermo Your photograph of the fire hydrants is superb and this includes the enlargement. Thanks for showing it to us. Roger - Original Message - From: pinhole-discussion-request@p at ??? To: pinhole-discussion@p at ??? Sent: Tuesday, August 21, 2001 3:04 PM Subject: Pinhole-Discussion digest, Vol 1 #409 - 14 msgs Send Pinhole-Discussion mailing list submissions to pinhole-discussion@p at ??? To subscribe or unsubscribe via the World Wide Web, visit http://www.pairlist.net/mailman/listinfo/pinhole-discussion or, via email, send a message with subject or body 'help' to pinhole-discussion-request@p at ??? You can reach the person managing the list at pinhole-discussion-admin@p at ??? When replying, please edit your Subject line so it is more specific than Re: Contents of Pinhole-Discussion digest... Today's Topics: 1. Enlarging (Christian Harkness) 2. try it (mvdtempor...@aol.com) 3. RE: questions commentsPop corn (Chuck Flagg) 4. Re: Courses (Jean Daubas) 5. Re: changing colours (rust...@aol.com) 6. Color Xerography transfers (Murray) 7. sharpness vs. depth-of-field (Murray) 8. Re: questions comments (Richard M. Koolish) 9. Re: questions comments (George L Smyth) 10. sharpness (Michel Dusariez) 11. Re: sharpness vs. depth-of-field (Guillermo) 12. compensating zone plate (Gordon J. Holtslander) 13. Re: compensating zone plate (Guillermo) 14. Re: sharpness (Howard Wells) --__--__-- Message: 1 To: pinhole-discussion@p at ??? Date: Fri, 17 Aug 2001 12:42:00 -0700 From: Christian Harkness chris.harkn...@eudoramail.com Cc: Organization: QUALCOMM Eudora Web-Mail (http://www.eudoramail.com:80) Subject: [pinhole-discussion] Enlarging Reply-To: pinhole-discussion@p at ??? Murray, I have enlarged 35mm pinhole images [used a body cap and home-made pinhole] to mural size, about four feet by seven feet, with no problem. Of course it does depend on the subject matter, and your vision of the image. chris --- http://ChristianHarkness.tripod.com Join 18 million Eudora users by signing up for a free Eudora Web-Mail account at http://www.eudoramail.com --__--__-- Message: 2 From: mvdtempor...@aol.com Date: Sat, 18 Aug 2001 00:06:43 EDT To: pinhole-discussion@p at ??? Subject: [pinhole-discussion] try it Reply-To: pinhole-discussion@p at ??? --part1_65.194747e4.28af43d3_boundary Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit OK - I will do my best not to ask any more questions until I finish my first roll and look at the results. My 7-year-old's first roll from a one-shot camera came back today...other than the blurry closeups of the wrong end of one of our cats she did alright. Murray --part1_65.194747e4.28af43d3_boundary Content-Type: text/html; charset=US-ASCII Content-Transfer-Encoding: 7bit HTMLFONT FACE=arial,helveticaFONT SIZE=2OK - I will do my best not to ask any more questions until I finish my first BRroll and look at the results. BR BRMy 7-year-old's first roll from a one-shot camera came back today...other BRthan the blurry closeups of the wrong end of one of our cats she did alright. BR BRMurray/FONT/HTML --part1_65.194747e4.28af43d3_boundary-- --__--__-- Message: 3 From: Chuck Flagg cfla...@home.com To: pinhole-discussion@p at ??? Subject: RE: [pinhole-discussion] questions commentsPop corn Date: Fri, 17 Aug 2001 23:17:57 -0700 Reply-To: pinhole-discussion@p at ??? The popcorn tin [once held three styles of popped corn- carmel,cheese, plain] is round. Later versions I poked the hole right in the side of the can. Both work really well and I have made bottom mounts which allow me to put them on a tripod too. Chuck Hi, I have a question on the pop corn tin. Is it rectangular or round? Why did you not just poke a hole in the pop corn tin Thanks for the info.It seems so simplified. John --__--__-- Message: 4 From: Jean Daubas j.dau...@free.fr To: pinhole-discussion@p at ??? Subject: Re: [pinhole-discussion] Courses Date: Sat, 18 Aug 2001 13:04:15 +0200 Reply-To: pinhole-discussion@p at ??? Hello, Tati, I do not directly know the Pinhole courses available in UK when you 'll be there but I think the following link may help you to find something : http://photocollege.net/FMPro?-db=PhotoColleges.fp3-format=wts.htm-SortFie ld=sortname-Max=all-findall Maybe the 1st part http://photocollege.net is sufficient. This link is part of the British Journal of Photography web-site and offers a lot of info on regular courses but also on workshop resources. Do not forget to have a look also in the Events page of the Royal Photographic Society at : http://www.rps.org/prog.html You will find there a calendar of various workshops, lectures, masterclasses , etc organized by the RPS. Hope it may help you, Have a good trip and keep on pinholing ! Cheers from
Re: [pinhole-discussion] sharpness
Sorry about not identifying the pinholes. They are the beach scene at the middle of the lefthand column and the image at the top of the righthand column. Both handheld using Ilford Delta 3200. As for the edges my lab prints with a filed-out negative carrier for me when I want the full image. The other images on the page are various forms of plastic camera, the self-portrait using a 17mm plastic lens on a 120 camera for that Sam Wang-ish circular image. I'm glad you like the images. Howard Wells Katharine Thayer wrote: Hi Howard, I like your images. I'm curious about the edges, which look handcoated to me. Do you use an alternative printing process? And since there are nine images on your page, which are the two you're talking about? Katharine Thayer Howard Wells wrote: And I have been delighted with the quality of 35mm pinhole photographs for years--either with homemade cameras, bodycaps or one of Dominique Stroobant's lens-less leica lenses. A couple of those images are at the address below. Both enlarge to make fine 8x10 prints. ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] compensating zone plate
Perhaps a silly, just-woke-up-and-checked-my-mail-while-still-sleepy kind of thought, but. What would happen if you projected a zone plate pattern of rings onto the surface of a largish half sphere? Wouldn't that bring the outer rings closer to the film plane? Would that help to compensate for fall off? I imagine you'd need a lot of rings. Also, I've long wondered why no one makes zone plates by etching and staining glass. Every zone plate I've seen has dirty, scratched, cloudy clear zones because it's been made on film base. Wouldn't glass be better? Could probably be done using photoetching. Maybe too complicated, probably too expensive. Colin __ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/
Re: [pinhole-discussion] sharpness
Hi Howard, I like your images. I'm curious about the edges, which look handcoated to me. Do you use an alternative printing process? And since there are nine images on your page, which are the two you're talking about? Katharine Thayer Howard Wells wrote: And I have been delighted with the quality of 35mm pinhole photographs for years--either with homemade cameras, bodycaps or one of Dominique Stroobant's lens-less leica lenses. A couple of those images are at the address below. Both enlarge to make fine 8x10 prints.
Re: [pinhole-discussion] sharpness
I agree with Michel. All the advertising for conventional photographic materials makes one think sharpness is the goal. I suppose it can be a legitimate goal for some purposes but not necessarily for expressive photography. I've spent a lot of time experimenting with ways to make modern materials less sharp. And I have been delighted with the quality of 35mm pinhole photographs for years--either with homemade cameras, bodycaps or one of Dominique Stroobant's lens-less leica lenses. A couple of those images are at the address below. Both enlarge to make fine 8x10 prints. Take pictures and enjoy. Howard Wells http://home.earthlink.net/~sandwell/work.html Michel Dusariez wrote: About pinhole sharpness. An other field in photography is to consider the artistic results first, put your magnifiers in your pocket and stop to search indefinitelly the performance, take pictures and enjoy. In the fields of sharpness nothing is never perfect, I know photographers who devote their entire life in search of performance, and never do real photography . Only tests, and test again ! Winners are only photography materials suppliers. Take your camera and take pictures. Michel DUSARIEZ ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] compensating zone plate
- Original Message - From: Gordon J. Holtslander hol...@duke.usask.ca A question for all the mathematicians and physicists. Is it possible to make a zone plate that compensates for fall-off. I am no mathematician or physicist, just a plain guy that sort of remember some of the math I studied more than 25 years ago. Is it possible to make a zone plate that compensates for fall-off. Is there a way of altering the line pattern and or line thickness of a zone plate so that the edges of the picture get more illumination? This are some thoughts: A ZP behaves just as a pinhole as far as fall-off is concerned. You could elongate the ZP so when you see it off-axis it resembless more a circle than an elipsis. But the only edges that will see the ZP more as a circle will be those toward which the ZP has been elongated. Also, you can only elongate vertically or horizontally (if you do both, you are effectively just making the ZP bigger and not good for the focal length in use, anymore). Fall-off is a relative measurement, the difference between the center and the edges, by elongating the ZP you will be getting not only more light at the edges but also at the center of the image, so the end result may not give us less fall-off than before. And just to make it interesting, if this is possible, is there a way of calibrating or predicting the difference in exposure from one region of the picture to another? Thanks G*D is not possible (IMO) otherwise I'd have to give you an answer!! Having said the above, the way to calculate it would be a Cos^4 law modified by the effect of the eliptical shaped aperture. The things I end up talking about over lunch with another pinholer! If you were in Quebec I'd probably ask you: what were you guys smoking, but probably in Saskatoon as well as in Toronto, eateries are smoke free places by law. :-) Guillermo
[pinhole-discussion] compensating zone plate
A question for all the mathematicians and physicists. Is it possible to make a zone plate that compensates for fall-off. When one makes an extremely wide angle shot the edges of the image are underexposed due to the signifcant difference in the focal length from the center to the edges of the film. Is there a way of altering the line pattern and or line thickness of a zone plate so that the edges of the picture get more illumination? And just to make it interesting, if this is possible, is there a way of calibrating or predicting the difference in exposure from one region of the picture to another? The things I end up talking about over lunch with another pinholer! Gord - Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca112 Science Place http://duke.usask.ca/~holtsgUniversity of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 -
