Re: [pinhole-discussion] Willarney's BB Idea
>- Original Message - >From: >To: >Sent: Thursday, March 13, 2003 6:12 PM >Subject: [pinhole-discussion] Willarney's BB Idea >Philip Willarney, I salute your brilliantly nutty idea! (And am not >surprised Ms. Merrill, our associate in wierdness, came out to >comment!). Now, given that an airgun bb has a diameter of .175", >we'll need Guillermo to tell us how far apart the inner sides of the >box need to be. Without taking my trusty slide ruler out to make the calculation, I can tell you it would need to be like the "mother of all pinhole cameras" (or not). Guillermo
[pinhole-discussion] Re: weird idea for a pinhole camera
Philip willarney wrote: > Stand away from the box, and fire a bb gun through > the middle of one of the sides. If the board is thin > enough, the bb should go through the box, through > the first film, through the second film, and out > again, causing 2 pinholes to be formed and > simultaneously taking a picture in both directions at > the same time! Strange enough to get me thinking about it. The typical BB is approximately 4.5 mm in diameter. In passing through cardboard it may not punch a perfectly clear hole, with the ragged edges of the cardboard collapsing back towards the center. A more circular hole may be possible if a lead pellet with a flat nose is used, though there may be some deformation of the pellet after passing through the first cardboard/film layer. The idea is just crazy enough to warrant some testing and sounds like a fine excuse to combine two hobbies. John Bolgiano --
Re: [pinhole-discussion] 120 mm zone plate
Hi folks Sorry to send this message to the list, but I'd like to contact Guillermo and I lost his email address. Please, could you contact me Guillermo jribe...@greco.com.br Thanks folks Joao - Original Message - From: Guillermo To: Sent: Monday, March 10, 2003 8:02 PM Subject: Re: [pinhole-discussion] 120 mm zone plate > > - Original Message - > From: "Daniel Bouman" > > > > have never used a zone plate before. I've just received a 120 mm f/80 > for > > use on a field camera and I have a few questions which I hope some one > will > > enjoy answering. It seems to me that I should set the camera's front > > standard 120mm from the film plane. > > Yes, a 120mm lens, be it Schneider, Nikon, Canon, etc. or Zone plate, is > made to focus "sharply" subjects at infinity when the lens is placed 120mm > from the film plane. > > > If so, what are the near and far > > limits of the field of "sharp" focus. > > Those are subjective limits with glass lenses, more so with pinhole and even > more so with ZP or pinhole sieves. Having focal length and f/stop you can > find those limits for your subjectivity by applying the lens formulas > available in the lens faq (google find the faq) > > > I've read that zone plates don't have > > the universal field of focus that pinholes have and can be focused. > > Yes, that's 'cause they do focus light. > > > If I > > extend the bellows for a close in shot then I'm not using the zone plate > at > > the focal length it was designed for, right? > > If you extend the bellows and your subject is not at infinity, you are not > using the lens at the focal length it was designed for, and it doesn't > matter if it is zoneplate or your expensive Rodenstock lens. When you > extend the bellows, you are increasing the "effective" focal length of the > lens, therefore you have to reduce the distance lens to subject, they have a > reciprocal relationship, you increase one you'll have to decrease the other. > In short, it is OK to use the ZP for a distance lens to film longer than > 120mm, provided your subject is closer to the camera. Again, refer to the > lens faq to find out how much you should extend the bellows for a particular > distance lens to film. Having said that, I wouldn't worry too much, I mount > my > zoneplates at the "calculated" distance and use them like that no matter > where the subject of my picture is. > > > Or is it that the depth of > > field at f/80 is big enough to cover a subject at a foot or two from the > > camera? Any takers? Cheers, Daniel Bouman > > In practical and for "lensless" imaging purposes the answer is yes. In > mathematical terms, you would have to extend the bellows beyond the focal > length distance the lens was calculated for. > > For instance: for your 120mm ZP and a subject at 2 feet (609.6mm) from the > lens, the bellows should be extended > > F=focal length the ZP was calculated for > S=distance lens to subject > I=bellows extension > > I = (S x F) / (S - F) > I = (609.6 x 120) / (609.6 - 120) > > I = 149.4mm > > Hope it helps, > > 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/ >
[pinhole-discussion] Willarney's BB Idea
Philip Willarney, I salute your brilliantly nutty idea! (And am not surprised Ms. Merrill, our associate in wierdness, came out to comment!). Now, given that an airgun bb has a diameter of .175", we'll need Guillermo to tell us how far apart the inner sides of the box need to be. Michael Georgoff San Jose, CA
Re: [pinhole-discussion] weird idea for a pinhole camera
Phillip Even if it has been done before you should consider doing it yourself and you may gain new insight or be led along a different path to a new revelation. Thomas Bachler the German born pinhole artist in his recent exhibition and book Arbeiten mit der Camera Obscura (Pinhole Exhibits), published parallel to the exhibition at Kunsterhaus, Gottingen. (2001) includes 'Scenes of Crime' - where 'shooting' a picture is achieved through firing a gun into an aperture-less camera containing the photosensitised material. The gun's trigger becomes the camera's shutter, penetrating the camera (and negative) making the exposure and transforming the scene into the 'scene of crime'. RB Ray Beckett P O Box 577 Coolangatta Q 4225 Australia Mobile: 0408 230 961 Email: rbeck...@bigpond.com URL: www.pinholephotography.com.au > --- Philip willarney wrote: > > pinhole-discussion@p at ??? > > > > The martial mood of the country led by some > > strange path to the following thought: > > > > Take a light tight cardboard box made of fairly > > thin cardboard: in the dark, securely tape film to > > two > > inner facing sides, and seal box. > > > > Take box outside, set it somewhere with a weight > > on top of it (a brick or rock). > > > > Stand away from the box, and fire a bb gun through > > the middle of one of the sides. If the board is > > thin > > enough, the bb should go through the box, through > > the first film, through the second film, and out > > again, causing 2 pinholes to be formed and > > simultaneously taking a picture in both directions > > at > > the same time! > > > > After a suitable exposure time, drop a slightly > > larger box on top of the first box to end the > > exposure. > > > > Has anyone done anything like this? Anyone want to > > try it and let me know how it works out? I haven't > > had a bb gun for, oh, 20 years, so I don't have the > > technology available... > > > > pw > > > > __ > > Do you Yahoo!? > > Yahoo! Web Hosting - establish your business online > > http://webhosting.yahoo.com > > > > ___ > > 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/ > > > __ > Do you Yahoo!? > Yahoo! Web Hosting - establish your business online > http://webhosting.yahoo.com > > ___ > 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] weird idea for a pinhole camera
I'll keep an eye out for that -- I haven't seen the revised ed. Yah, you might need something bigger than a bb gun, but a bb gun is "relatively" safe (oddly enough, we don't get *nearly* as many "don't do that, it's dangerous" flame wars on the pinhole list as we do over on the alt-processes list :^). My family had a .22 rifle when I was a kid, but I haven't had a firearm in the house since... So, note to anyone: use this idea at your own risk! If you get hurt trying this idea, it's your own responsibility! I think I'll ask around and see if someone I know has a bb gun I could use to try this out with... -- pw --- "D. Hill" wrote: > In the revised edition of Renner's Pinhole (I can't > remember where and too lazy to look) someone did > what > you are attempting as a self-portrait - Very Cool. > I > believe it was a much more powerful projectile > though. > > Don > > > --- Philip willarney wrote: > > pinhole-discussion@p at ??? > > > > The martial mood of the country led by some > > strange path to the following thought: > > > > Take a light tight cardboard box made of fairly > > thin cardboard: in the dark, securely tape film to > > two > > inner facing sides, and seal box. > > > > Take box outside, set it somewhere with a weight > > on top of it (a brick or rock). > > > > Stand away from the box, and fire a bb gun through > > the middle of one of the sides. If the board is > > thin > > enough, the bb should go through the box, through > > the first film, through the second film, and out > > again, causing 2 pinholes to be formed and > > simultaneously taking a picture in both directions > > at > > the same time! > > > > After a suitable exposure time, drop a slightly > > larger box on top of the first box to end the > > exposure. > > > > Has anyone done anything like this? Anyone want > to > > try it and let me know how it works out? I > haven't > > had a bb gun for, oh, 20 years, so I don't have > the > > technology available... > > > > pw > > > > __ > > Do you Yahoo!? > > Yahoo! Web Hosting - establish your business > online > > http://webhosting.yahoo.com > > > > ___ > > 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/ > > > __ > Do you Yahoo!? > Yahoo! Web Hosting - establish your business online > http://webhosting.yahoo.com > > ___ > 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/ __ Do you Yahoo!? Yahoo! Web Hosting - establish your business online http://webhosting.yahoo.com
RE: [pinhole-discussion] Agfa Multicontrast Premium ASA
Marcelo: DUCK! --- On Thu 03/13, Marcelo Mammana < mmamm...@yahoo.com > wrote: Subject: [pinhole-discussion] Agfa Multicontrast Premium ASA 3-Is there any female hormones in the manufacturing of the paper, so they change some days during the month? (no answers expected for question 3) Thanks for your help Marcelo ___ No banners. No pop-ups. No kidding. Introducing My Way - http://www.myway.com
[pinhole-discussion] Agfa Multicontrast Premium ASA
Hi,
Here is my problem:
I use Agfa Multicontrast Premium, in 2 different
pinhole cameras (one with 95mm focal lenght, f/290),
and the second with 25mm focal lenght, f/155) and
using the same light-meter and the same correction
factors for reciprocity (charts for exposure from
Mr.Pinhole Calculators, and factors for reciprocity,
from G.Penate's and Penultimate's websites).
The manufacturers chart, for when using the paper
under the enlarger light, says that the paper has an
ASA of 400p ("p" meaning paper?) when is used without
filters, ASA160p when using contrast filters from 00
to 3.5, and ASA80p, when using with filters from 4 up.
Now, when I use the first camera, I get the best
exposures when calculate them as if the paper is
ASA64, but this is variable depending on the day
(always measuring something close to a medium gray).
For the second camera (a plastic 35mm film canister),
best ASA is 125.
In many Internet sources I've found that some people
uses ASA 6 for paper and a very simple chart for
reciprocity (1'', 10'' and 100'', corrected opening up
1,2 or 3 stops), but this definitely makes grossy
underexposed photos in my cameras.
So,
1-what's the ASA of a paper?
2-Can, the same paper behave different just because
the focal lenght differs (speaking about ASA, not
exposure. Exposure will be compensated with the
different aperture)?
3-Is there any female hormones in the manufacturing of
the paper, so they change some days during the month?
(no answers expected for question 3)
Thanks for your help
Marcelo
Marcelo Mammana
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Yahoo! Web Hosting - establish your business online
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Re: [pinhole-discussion] weird idea for a pinhole camera
In the revised edition of Renner's Pinhole (I can't remember where and too lazy to look) someone did what you are attempting as a self-portrait - Very Cool. I believe it was a much more powerful projectile though. Don --- Philip willarney wrote: > pinhole-discussion@p at ??? > > The martial mood of the country led by some > strange path to the following thought: > > Take a light tight cardboard box made of fairly > thin cardboard: in the dark, securely tape film to > two > inner facing sides, and seal box. > > Take box outside, set it somewhere with a weight > on top of it (a brick or rock). > > Stand away from the box, and fire a bb gun through > the middle of one of the sides. If the board is > thin > enough, the bb should go through the box, through > the first film, through the second film, and out > again, causing 2 pinholes to be formed and > simultaneously taking a picture in both directions > at > the same time! > > After a suitable exposure time, drop a slightly > larger box on top of the first box to end the > exposure. > > Has anyone done anything like this? Anyone want to > try it and let me know how it works out? I haven't > had a bb gun for, oh, 20 years, so I don't have the > technology available... > > pw > > __ > Do you Yahoo!? > Yahoo! Web Hosting - establish your business online > http://webhosting.yahoo.com > > ___ > 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/ __ Do you Yahoo!? Yahoo! Web Hosting - establish your business online http://webhosting.yahoo.com
